Troubleshooting Cisco Ip Telephony Networking Technology Paul Giralt
Troubleshooting Cisco Ip Telephony Networking Technology Paul Giralt
Troubleshooting Cisco Ip Telephony Networking Technology Paul Giralt
Troubleshooting Cisco Ip Telephony Networking Technology Paul Giralt
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5. About the Authors
Paul Giralt, CCIE No. 4793, is an escalation engineer at the Cisco Systems Technical
Assistance Center in Research Triangle Park, N.C., where he has worked since 1998.
He has been troubleshooting complex IP Telephony networks since the release of
CallManager 3.0 as a TAC engineer, a technical lead for the Enterprise Voice team,
and now as an escalation engineer supporting the complete Cisco line of IP
Telephony products. Paul has troubleshot problems in some of Cisco's largest IP
Telephony deployments and has provided training for TAC teams around the globe.
Prior to working on IP Telephony, he was a TAC engineer on the LAN Switching team.
He holds a B.S. in computer engineering from the University of Miami.
Addis Hallmark, CCNA, CIPT, is a senior technical marketing engineer with Cisco
Systems. He has been installing, configuring, administering, and troubleshooting the
Cisco IP Telephony solution since the 2.3 release of CallManager. He has contributed
to numerous design guides, application notes, and white papers on a variety of IP
Telephony subjects, including CallManager, IP Phones, and IP gateways.
Anne Smith is a technical writer in the CallManager engineering group at Cisco
Systems. She has written technical documentation for the Cisco IP Telephony
solution since CallManager release 2.0 and was part of the Selsius Systems
acquisition in 1998. Anne writes internal and external documents for CallManager, IP
phones, and other Cisco IP Telephony products. She is a co-author of Cisco
CallManager Fundamentals (ISBN: 1-58705-008-0) and Developing Cisco IP Phone
Services (ISBN: 1-58705-060-9), both from Cisco Press.
About the Technical Reviewers
Shawn Armstrong is an IT engineer working in Cisco's Core Hosting group. She has
been with Cisco for four years and is responsible for managing NT and Windows 2000
servers within Cisco's Information Technology group.
Dave Goodwin, CCIE No. 4992, is a customer diagnostic engineer for Cisco's
Advanced Engineering Services. He is responsible for discovering and resolving
problems in new Cisco IP Telephony products while administering internal field trials
for these systems. He also works closely with Cisco's development and TAC support
teams to provide support for anything from troubleshooting to quality issues to tools.
He has been at Cisco for almost five years and has worked as a network engineer for
eight years.
Christina Hattingh is a member of the Technical Marketing organization at Cisco
Systems. In this role she works closely with product management and engineering.
Christina focuses on helping Cisco sales engineers, partners, and customers design
and tune enterprise and service provider Voice over Packet network infrastructures
with particular focus on QoS. Prior to this she was a software engineer and
engineering manager of PBX Call Center products at Nortel Networks. Her earlier
software development experience in X.25 and network management systems provide
background for the issues involved today in migrating customers' traditional data and
voice networks to packet-based technologies. Christina has a graduate degree in
computer science and mathematical statistics.
Phil Jensen, CCIE No. 2065, is a consulting systems engineer for Cisco in the
southeastern U.S. He has focused on helping Cisco's largest customers design and
troubleshoot AVVID IP Telephony solutions for the past three years. He has worked
as a network engineer for more than 14 years.
6. Ketil Johansen, CCIE No. 1145, is a business development manager with Cisco
Systems, working with companies integrating their applications with Cisco
CallManager. He has worked with networking technologies for more than 18 years
and has been a CCIE since 1994. The last three years he has focused on IP
Telephony technologies.
Chris Pearce is a technical leader in the Cisco CallManager software group at Cisco
Systems, Inc. He has ten years of experience in telecommunications. His primary
areas of expertise include call routing, call control, and telephone features. He was a
member of the team that developed and implemented the Cisco CallManager
software from its early stages, and he was directly involved in developing the system
architecture and design.
Ana Rivas, CCIE No. 3877, is an escalation engineer in Cisco's EMEA region. She is
one of the technical leaders for AVVID solutions in the Cisco TAC. She is responsible
for technically leading the resolution of some of the most critical problems in voice
and IP Telephony, spreading technical knowledge to other teams, and working with
Cisco business units and the field to head IP Telephony solutions. She has been
working as a network engineer for more than five years.
Markus Schneider, CCIE No. 2863, is a diagnostic engineer for Cisco's Advanced
Engineering Services. He is responsible for helping Cisco customers design,
implement, and troubleshoot IP Telephony solutions in their environment. He has
been working for Cisco as a network engineer for more than six years.
Gert Vanderstraeten has been working as a telecom/datacom engineer for
companies such as Alcatel, Bell, and Lucent Technologies since 1993. Since 1998 he
has been an independent contractor for the Cisco Systems' IT department. During
the course of his tenure, his main focus has been the design, implementation, and
maintenance of VoIP, IP Telephony, voice and video applications, and the integration
of AVVID technologies into solutions. He is currently operating within the Cisco
Systems global Enterprise Architecture Solutions team.
Liang Wu is a software engineer in the CallManager software group at Cisco
Systems, Inc. For the last seven years, he has been focusing on PBX/Enterprise
communication systems. He spent more than eight years in the Class 4/5/AIN
telephone switching industry.
Acknowledgments
Paul Giralt
I want to first thank Anne Smith for all her hard work and guidance throughout this
entire project. There is no way this book would exist without her constant dedication
and attention to detail.
Thanks to Chris Cleveland for his excellent work as development editor on this book
and for being so flexible when it comes to the unpredictable schedules of a TAC
engineer.
Thank you to the worldwide Enterprise Voice and AVVID TAC teams, especially the
RTP Enterprise Voice team for being such a world-class group of engineers to work
with.
Thanks to the RTP Voice Network Team (VNT) for all the excellent VoX
documentation. Special thanks to Gonzalo Salgueiro and Mike Whitley for the VoX
boot camp material and to Steve Penna for knowing everything.
Thanks to Dave Hanes for his excellent fax troubleshooting presentations and Andy
Pepperell for his explanation of fax and modem passthrough.
7. Thanks to all the technical reviewers—Ana Rivas, Chris Pearce, Dave Goodwin, Ketil
Johansen, Markus Schneider, Phil Jensen, Gert Vanderstraeten, Liang Wu, Shawn
Armstrong, and especially Christina Hattingh—for always being on top of everything
in the world of Cisco IOS gateways.
Thanks to all the developers in Richardson and San Jose that I have worked with
over the years. Your insight into the inner workings of CallManager has helped me
understand how to better troubleshoot the product. Special thanks to Bill
Benninghoff for always answering any question I throw his way and for always being
so thorough in his explanations. Also thanks to Chris Pearce for his excellent grasp
on the intricacies of call routing.
Thank you to all the contributors to the VNT Voice University website as well as the
AVVID TAC tips website on Cisco.com. Also thanks to all the other unnamed authors
for the documentation scattered throughout various web pages.
Thanks to all the customers I have worked with over the past several years on
AVVID issues for being my teachers. Every customer I work with helps me
understand a little more about IP Telephony.
Addis Hallmark
First, I'd like to thank Paul Hahn and Richard Platt for bringing me on at Cisco. Paul
in particular spent a lot of time with me, bringing me up to speed on these
technologies, and for that, I am indebted to him.
I'd also like to thank all the brilliant development engineers who patiently helped me
understand CallManager so well over the past few years.
I'd like to thank Susan Sauter. She is a brilliant engineer, and so much of what I
know about IP Phones came from her patient instruction.
Chris Pearce has also helped me so much over the last few years in understanding
dial plans.
The chapter on applications is based on the hard work of Dave Bicknell. Without his
efforts, that chapter would not be even close to what it should be.
Manish Gupta and his team were a tremendous source of help on the LDAP Directory
chapter. Stefano Giorcelli's excellent directory documentation also was so very
helpful!
The TAC is on the front lines of troubleshooting, and much of the help I received was
from the experiences that only solid TAC engineers could provide.
Also, the technical reviewers of this book were so helpful. Thank you so much to
everyone for their hard work!
I really believe this is a great book, and one of the biggest reasons for that is Paul
Giralt's invaluable contribution and hard work on this project. I couldn't have done
this without him!
My manager, Shaik Kaleem, was very supportive of this project that I undertook on
my own time, and I greatly appreciate that support.
Finally, I'd like to thank Anne Smith. This project would never have happened
without her tireless work and skillful help. I am so grateful for Anne's effort. She
worked so very hard over this past year, and Paul Giralt and I would have been lost
without her.
Anne Smith
My many thanks go to Paul Giralt and Addis Hallmark for making this book a reality
with their knowledge, experience, hard work, and sacrifice. In particular, I thank Paul
for a highly enjoyable working experience. Paul's dedication to the quality, accuracy,
and comprehensiveness of this book was unsurpassed; he spent countless hours
reviewing every page of technical information and his experience with the many
components in the Cisco AVVID IP Telephony solution made his extensive
contribution invaluable. At every turn, Paul's dedication, commitment to quality,
8. tireless drive for accuracy, and constant positive attitude made working with him a
rewarding experience.
As always, my thanks and great admiration go to Richard Platt and Scott Veibell.
Without their continued support there would be no Cisco IP Telephony-related Cisco
Press books.
I would like to thank Chris Pearce for his help on the Call Routing chapter, Travis
Amsler for his assistance on the Cisco CRA and extension mobility sections, and
Brian Sedgley and Ken Pruski for their help with CCM and SDL tracing. Appreciation
and recognition also go to the engineers who created and developed Dick Tracy: Rick
Baugh, Jim Brasher, Long Huang, and David Patton.
Foreword
In November of 1998, Cisco Systems acquired a small startup called Selsius Systems.
For over a year this small company had been shipping the world's first IP phones and
Windows NT-based call management software consisting of close to a million lines of
C++ code with a small development staff of about 40 engineers. Since the
acquisition, the code base has evolved into many millions of lines of C++, XML, and
Java code, and the development staff now has over 500 engineers. The level of
sophistication and capability has increased dramatically and is a key component of
the Cisco Architecture for Voice, Video, and Integrated Data (AVVID). Current
deployments range from extremely distributed enterprises with hundreds of remote
offices to small 50-person offices. Geographically, systems are deployed across the
world, including exotic locations such as Antarctica and the International Space
Station!
AVVID's IP Telephony components (including the IP phones, gateways, and Cisco
CallManager) comprise a telephony system that is both richer than and different from
traditional TDM-based phone systems. For example, manageability and serviceability
are achieved through either a browseable interface or an XML SOAP-based protocol
for integration with existing IT systems. Geography disappears as a problem because
telephony functions, manageability, and serviceability all traverse the IP network.
Proprietary databases disappear in favor of standard SQL databases and LDAP
directories. Nevertheless, this unification and standardization of telephony on IP
networks also presents unique challenges. Voice quality can be impacted by poor IP
network design. Capacity planning requires consideration of IP address numbering.
Music on Hold as a multicast stream requires proper switch and router configuration.
These are only a few examples of the unique considerations that must be given to IP
Telephony deployments.
This book incorporates the authors' real-life experiences in planning and
troubleshooting IP Telephony within the AVVID solution. The wisdom contained
herein has been gained over the course of thousands of real customer experiences.
Paul Giralt and Addis Hallmark are two of the very best troubleshooters in the
industry, and Anne Smith has written about and worked with the system since the
earliest releases. Paul has been with Cisco's customer support organization for
several years. His depth and breadth of knowledge across all Cisco products are
legendary, including his most recent focus on IP Telephony. I have seen him in
action at some very large and sensitive customer installations, where he resolved
extremely difficult problems and provided excellent guidance during upgrades and
installations. We were fortunate to get him back, inasmuch as our customers were
loathe to let him leave! Addis has been involved in the development and testing of
many AVVID products. He has been personally engaged with many key customers
9. during deployment and operation and has received numerous rave reviews from
customers. Addis also has been instrumental in the security design aspects of Cisco
CallManager. Anne is an author and the technical editor for this and several other
AVVID books. She has been engaged with the technology since its inception at
Selsius Systems.
I highly recommend this book to any individual or organization involved in installing,
operating, or troubleshooting one of the most exciting advances in the long history of
telephony. Written by three of its pioneers, this book serves as a guide for the rest of
the pioneers who aren't afraid to help their organization communicate in its own way,
the better way, the IP way.
Richard B. Platt
Vice President for Enterprise Voice, Video Business Unit
Cisco Systems, Inc.
Introduction
This book teaches you the troubleshooting skills you need to isolate and resolve IP
telephony problems. IP telephony is a relatively new technology with many different
components. The Cisco IP Telephony (CIPT) solution revolves around Cisco
CallManager, the core call processing engine. CIPT includes many different endpoints,
such as IP phones, various gateways, and various applications such as Cisco IP IVR,
Cisco CallManager Attendant Console, Cisco IP SoftPhone, Cisco Conference
Connection, extension mobility, and more. Additionally, the network infrastructure
plays an important role in prioritizing voice packets to ensure quality of service
(QoS).
With all these components involved in transmitting voice across packet networks, it
is essential that you be able to identify and resolve issues in the entire solution. This
requires knowledge of the functionality of these components and how they interact
with each other, as well as what tools are available to help you find the root cause
when problems arise. This book educates you about the techniques, tools, and
methodologies involved in troubleshooting an IP telephony system.
Target CallManager Release
This book is written to CallManager release 3.3. Updates to this book may be
provided after publication. You should periodically check the ciscopress.com web site
for updates (go to ciscopress.com and search for "Troubleshooting Cisco IP
Telephony").
Goals and Methods
This book intends to deliver a methodology you can follow when troubleshooting
problems in an IP telephony network, particularly a Cisco IP Telephony solution. This
book provides detailed troubleshooting information that applies to a variety of
problems that can occur in any IP telephony deployment.
"Best Practices" sections in each chapter provide tips and design considerations to
help you avoid common configuration problems.
10. Who Should Read This Book?
This book is designed to teach you how to isolate and correct problems in an IP
telephony network. If you are a networking professional responsible for
administering a Cisco IP Telephony (CIPT) system, this book is for you. Although this
book's main focus is on CIPT, some concepts apply to IP telephony in general as well.
You will best be able to assimilate the information in this book if you already have a
working knowledge of a CIPT network.
How This Book Is Organized
Although you could read this book cover-to-cover, it is designed to help you find
solutions to specific problems. The chapters are organized by the various
components of a Cisco IP Telephony solution. Four appendixes provide reference
information.
• Chapter 1, "Troubleshooting Methodology and Approach"— You can
troubleshoot even the most complex problems if you have a good
methodology in place for finding the root cause. This chapter focuses on
teaching that methodology: learning how to find clues and track down your
"suspect" by breaking the problem into smaller pieces and tackling each piece
individually.
• Chapter 2, "IP Telephony Architecture Overview"— Cisco AVVID
includes many different components that come together to form a
comprehensive architecture for voice, video, and integrated data. This
chapter covers the basic components of the IP Telephony architecture in order
to provide a big-picture view of the system.
• Chapter 3, "Understanding the Troubleshooting Tools"— To effectively
troubleshoot problems in a Cisco IP Telephony network, you must be familiar
with the many tools at your disposal. In addition, you need to know how to
best use those tools to achieve maximum results. This chapter describes the
various tools and their different uses.
• Chapter 4, "Skinny Client Registration"— IP phone registration is a
common source of problems. This chapter describes how Skinny protocol-
based device registration works, including discussions of inline power,
network connectivity, and potential TFTP and CallManager issues.
• Chapter 5, "IP Phones"— IP phones can encounter various problems, from
unexpected resets to directory and service problems, and more. This chapter
explains proper IP phone behavior and examines problems that can occur
after an IP phone successfully registers.
• Chapter 6, "Voice Gateways"— Voice gateways are the interface that
bridges the Voice over IP (VoIP) world with the Public Switched Telephone
Network (PSTN). Voice gateways can be Cisco IOS Software gateways or
modules within voice-enabled LAN switches. They can be analog or digital,
and they can use a wide variety of signaling protocols. This chapter teaches
you how to identify and resolve gateway problems by breaking these
components into logical groups and following a methodical troubleshooting
approach.
• Chapter 7, "Voice Quality"— Voice quality is a broad term that covers the
following conditions: delayed audio, choppy or garbled audio, static and noise,
one-way or no-way audio, and echo. This chapter focuses on the information
11. you need to investigate and resolve voice quality problems in an IP Telephony
network.
• Chapter 8, "Fax Machines and Modems"— Fax machines and modems
present unique challenges when carried over an IP Telephony network,
primarily due to their unforgiving nature concerning any modification to the
audio stream. This chapter discusses the effect of packet loss and jitter, fax
passthrough, fax relay, and how to troubleshoot modems and faxes.
• Chapter 9, "Call Routing"— Possessing a strong understanding of call
routing is arguably one of the most important aspects of a smooth-operating
CIPT solution. This chapter discusses closest-match routing, calling search
spaces and partitions, transformations, and translation patterns as well as
troubleshooting hold, transfer, park, and call pickup.
• Chapter 10, "Call Preservation"— Call preservation is easier to predict
when you understand the protocol interaction with CallManager. This chapter
provides guidelines for determining call survivability based on endpoint type
and protocol.
• Chapter 11, "Conference Bridges, Transcoders, and Media Termination
Points"— Conference bridges, transcoders, and media termination points are
media resources. This chapter discusses the role of media resource groups
and media resource group lists, codec selection, and troubleshooting
transcoder and conference bridge resources.
• Chapter 12, "Music on Hold"— The Music on Hold feature allows callers to
hear streaming audio while on hold. This chapter describes this feature and
provides steps to take if you encounter problems.
• Chapter 13, "Call Admission Control"— Call admission control is used in
situations where a limited amount of bandwidth exists between telephony
endpoints such as phones and gateways. This chapter discusses the two types
of call admission control—locations-based and gatekeeper—and the
mechanisms available to reroute calls through the PSTN in the event of WAN
congestion.
• Chapter 14, "Voice Mail"— CallManager is compatible with a variety of
voice mail systems that integrate with CallManager through various methods.
This chapter focuses on troubleshooting the integration of CallManager and
three types of voice mail systems: Cisco Unity, third-party voice mail systems
integrated via Simple Message Desk Interface (SMDI), and Octel Voice Mail,
integrated through Cisco DPA Voice Mail gateways.
• Chapter 15, "Survivable Remote Site Telephony (SRST)"— SRST allows
a router at a remote branch to assume call processing responsibilities in the
event that phones at a remote site are unable to contact the central
CallManager. This chapter describes SRST and provides detailed information
about the various problems that can occur.
• Chapter 16, "Applications"— Cisco AVVID allows for the creation of many
different applications to interoperate within the converged network. This
chapter discusses some of the primary applications in a Cisco AVVID IP
Telephony solution, such as IP AA and IP IVR, extension mobility, Cisco IP
SoftPhone, Personal Assistant, and Cisco CallManager Attendant Console.
• Chapter 17, "SQL Database Replication"— The SQL relational database
stores the majority of CallManager configuration information. This chapter
discusses the Publisher-Subscriber model for database replication, name
resolution, Enterprise Manager, Replication Monitor, broken subscriptions, and
CDR database replication.
• Chapter 18, "LDAP Integration and Replication"— User information is
stored in a Lightweight Directory Access Protocol (LDAP) database. This
12. chapter describes directory integration versus directory access, using the
CallManager embedded directory, and integrating with Active Directory and
Netscape iPlanet.
• Appendix A, "Cisco IP Telephony Protocol and Codec Information and
Reference"— Cisco IP Telephony employs many different protocols and
codecs. This appendix provides a list of applicable protocols and codecs with
descriptions and the standards body corresponding to the protocol or the
Request for Comments (RFC) number. Compression rates are given for each
codec.
• Appendix B, "NANP Call Routing Information"— CallManager provides a
built-in dial plan for the North American numbering plan (NANP). This
appendix provides information from the NANP file located in the C:Program
FilesCiscoDial Plan directory. This file shows you how each part of an NANP
number corresponds to a specific placeholder. It is particularly useful when
you're learning how to apply route filters.
• Appendix C, "Decimal to Hexadecimal and Binary Conversion Table"—
This appendix provides a cheat sheet that shows you how to quickly convert
between decimal, hexadecimal, and binary values.
• Appendix D, "Performance Objects and Counters"— Microsoft
Performance (PerfMon) and the Real-Time Monitoring Tool allow you to
monitor your system through the use of performance counters. This appendix
lists and describes the performance objects and counters in a Cisco IP
Telephony network. Some pertinent Windows 2000 counters are also
described.
• Glossary— The glossary defines terms and acronyms used in this book.
Best Practices
In a perfect world, there would be no need for this book, because systems would
always run perfectly. Unfortunately, in the real world, problems do arise, and they
usually don't go away on their own. However, an administrator/installer can
proactively take steps to ensure reliability and high availability and minimize the
number of problems that arise.
Best practices include not only design considerations but also monitoring and
management. A properly monitored system can detect failures before they become
service-affecting. Each chapter contains a section outlining best practices as they
apply to the chapter topic.
In a properly designed network, you can achieve 99.999 percent reliability—a rating
that is expected of a telephone system.
High Availability in an IP Telephony Environment
High availability for IP telephony is based on distribution and core layers in
the network and servers (call processing, application servers, and so on).
BellCore Specification GR-512 defines what criteria must be met to achieve
"five 9s" (99.999 percent) reliability. A careful examination of this document
is recommended if you are interested in understanding 99.999 percent
reliability. Note that many "events" are not counted against five 9s
reliability. Some of these events include the following:
• Outages of less than 64 devices
13. • Outages less than 30 seconds in duration
• Outages due to outside causes, such as power loss from utility or
network circuit failures caused by the provider
• Outages due to planned maintenance
The Cisco AVVID IP Telephony solution can achieve 99.999 percent
reliability per the BellCore FR-512 specification.
Command Syntax Conventions
The conventions used to present command syntax in this book are the same
conventions used in the IOS Command Reference. The Command Reference
describes these conventions as follows:
• Vertical bars | separate alternative, mutually exclusive elements.
• Square brackets [ ] indicate an optional element.
• Braces { } indicate a required choice.
• Braces within brackets [{ }] indicate a required choice within an optional
element.
• Boldface indicates commands and keywords that are entered literally as
shown. In actual configuration examples and output (not general command
syntax), boldface indicates commands that the user inputs (such as a show
command).
• Italic indicates arguments for which you supply actual values.
OSI Reference Model
Throughout the book, a few references are made to the OSI model. Table I-1
provides a brief primer on the OSI reference model layers and the functions of each.
You can learn more about the OSI model in any of the Cisco Press books that target
the CCNA certification.
Table I-1. OSI Reference Model Overview
OSI Layer
Name
Functional Description Examples
Physical
(Layer 1)
Responsible for moving bits of data between
devices. Also specifies characteristics such as
voltage, cable types, and cable pinouts.
EIA/TIA-232, V.35
Data link
(Layer 2)
Combines bytes of data into frames.
Provides access to the physical media using a
Media Access Control (MAC) address, which is
typically hard-coded into a network adapter. Also
performs error detection and recovery for the
data contained in the frame.
802.3/802.2,
HDLC
Network Uses logical addressing which routers use for IP, IPX
14. Table I-1. OSI Reference Model Overview
OSI Layer
Name
Functional Description Examples
(Layer 3) path determination. Can fragment and
reassemble data if the upper-layer protocol is
sending data larger than the data link layer can
accept.
Transport
(Layer 4)
Provides reliable or unreliable delivery of data
packets. Allows for multiplexing of various
conversations using a single network-layer
address. Can also ensure data is presented to the
upper layers in the same order it was
transmitted. Can also provide flow control.
TCP, UDP
Session
(Layer 5)
Sets up, coordinates, and terminates network
connections between applications. Also deals with
session and connection coordination between
network endpoints.
Operating systems
and application
access scheduling
Presentation
(Layer 6)
Defines how data is presented to the application
layer.
Can perform special processing, such as
encryption, or can perform operations such as
ensuring byte-ordering is correct.
JPEG, ASCII
Application
(Layer 7)
Interface between network and application
software.
Telnet, HTTP
Comments for the Authors
The authors are interested in your comments and suggestions about this book.
Please send feedback to the following address:
troubleshootingcipt@external.cisco.com
Further Reading
The authors recommend the following sources for more information.
Cisco Documentation
This book provides comprehensive troubleshooting information and methodology.
However, details about common procedures might not be provided. You should be
familiar with and regularly use the documentation that is provided with the Cisco IP
Telephony system to supplement the information in this book.
You can find Cisco IP Telephony documentation by searching for a specific product on
Cisco.com or by starting at the following link:
15. www.cisco.com/univercd/cc/td/doc/product/voice/index.htm
You can examine the following books at a technical bookseller near you or online by
entering the title in the search box at www.ciscopress.com.
Cisco CallManager Fundamentals: A Cisco AVVID Solution
You can find detailed information about CallManager's inner workings in the book
Cisco CallManager Fundamentals (ISBN 1-58705-008-0).
Developing Cisco IP Phone Services: A Cisco AVVID Solution
You can find instructions and tools for creating custom phone services and directories
for Cisco IP Phones in the book Developing Cisco IP Phone Services (ISBN 1-58705-
060-9).
Cisco IP Telephony
You can find installation, configuration, and maintenance information for Cisco IP
Telephony networks in the book Cisco IP Telephony (ISBN 1-58705-050-1).
Integrating Voice and Data Networks
You can find information on how to integrate and configure packetized voice
networks in the book Integrating Voice and Data Networks (ISBN 1-57870-196-1).
Cisco Router Configuration, Second Edition
Cisco Router Configuration, Second Edition (ISBN 1-57870-241-0) provides example-
oriented Cisco IOS Software configuration for the three most popular networking
protocols used today—TCP/IP, AppleTalk, and Novell IPX.
Icons Used in This Book
Throughout this book, you will see a number of icons used to designate Cisco-specific
and general networking devices, peripherals, and other items. The following icon
legend explains what these icons represent.
16. IFC
Active Directory domain name problems
Active Directory integration troubleshooting and overview
Active Directory schema modifications
Active Directory—users added in Active Directory don't show up in CallManager
Administration
Adding a user fails
Alarms (red and yellow) on a digital interface
"Already in conference" message
Attendant Console client configuration
Attendant Console—fast busy on calls to a pilot point
Attendant Console—line states won't update
Attendant Console—lines are disabled
Attendant Console—login failed
Attendant Console—longest idle algorithm is not working properly
Attendant Console—new user doesn't display
17. Attendant Console server configuration
Attendant Console—some line states show Unknown status
Attendant Console troubleshooting methodology
Attendant Console—wrong directory list displays
Audio problems
Audio Translator problems
Automated alternate routing (AAR) troubleshooting
Busy signal not heard on an IP phone
Calling name display problems
Calling search spaces, overview
CallManager Serviceability
CallManager wildcard summary
Call preservation, overview
Call routing problems
CCM traces—how to read
CCM traces—how to read Skinny messages
CDRs are not being written properly
CDRs are not generated by Subscriber
Choppy audio
"CM Down, Features Disabled" message
"CM Fallback Service Operating" message
CMI—reading traces
Codec selection between devices
Conference bridge—out of resources
Conference Connection doesn't work
Corporate directory—add or delete users fails in CallManager Administration
Corporate directory—Error: "The phone administrator is currently not allowed to add
or delete users"
CRA Administration page does not load
CRA Application Engine problems
CRA directory configuration troubleshooting
CRA trace files (MIVR)
Customer Directory Configuration Plugin troubleshooting
Database Layer Monitor is not running properly
Database replication problems
D-channel won't establish on PRI
DC Directory—reconfiguring in CallManager 3.3
DC Directory—reconfiguring in pre-3.3 CallManager
Directory access troubleshooting
Directory troubleshooting
Delayed audio
Delayed routing
Dial peer matching in IOS, overview
Dick Tracy
Digit discard instructions (DDIs), overview
directories button doesn't work
Disconnected calls with cause code 0xE6, "Recovery on timer expiry."
DPA 7610/7630—MWI problems
Dropped calls
Dropped packets
DTMF relay, overview
E1 interface troubleshooting
Echo problems
18. "Exceeds maximum parties" message
Extension mobility—common error messages
Extension mobility problems on CallManager release 3.1 or 3.2
Extension mobility problems on CallManager release 3.3
Extension mobility troubleshooting methodology for CallManager release 3.1 or 3.2
Failover—phone behavior and causes
Fax machine troubleshooting methodology
Fax passthrough configuration
Fax passthrough, overview
Fax relay debugs, enabling
Fax relay, overview
Fax takes twice as long to complete
FXO port will not disconnect a completed call
Garbled audio
Gatekeeper call admission control
H.323 call flow (H.225 and H.245)
Hold and resume problems
Hold doesn't play music
Intercluster trunk troubleshooting
IOS gateway—call routing and dial peer debugs
IOS gateway debugs
IOS gateway—debugs and show commands
IOS gateway—diagnosing the state of ports
IOS gateway—TDM interfaces
IOS gateway won't register with CallManager (MGCP)
iPlanet integration troubleshooting
ISDN cause codes (Q.850)
ISDN messages, overview
ISDN timers, overview
Jitter
Live audio source problems
LMHOSTS file, overview
Locations-based call admission control
Masks, overview
Methodology for troubleshooting
MGCP overview
Microsoft Performance (PerfMon)
Modem passthrough configuration
Modem passthrough, overview
Modem troubleshooting methodology
MOH—live audio source problems
MOH—multicast and unicast problems
MOH—no music when calls are on hold
MOH—reading CCM traces
MOH—troubleshooting methodology
MWI problems (Personal Assistant)
MWI problems (SMDI)
MWI problems (Unity)
MWI problems (VG248)
"No conference bridge available" message
No-way audio
Octel integration
One-way audio
19. Outside dial tone played at the wrong time
Park problems
Partitions, overview
Personal Assistant is not intercepting calls
Personal Assistant—MWI problems
Phone—busy signal not heard
Phone—failover and failback
Phone—inline power problems
Phone—network connectivity and Skinny registration
Phone stuck in SRST mode
Phone—switch port operation
Phone—TFTP configuration file
Phone—understanding the difference between restart and reset
Phone—understanding the Skinny protocol
Phone—VLAN configuration
Phone won't register
Pickup/group pickup problems
PRI backhaul channel status
PRI—CallManager sends the proper digits to the PSTN, but call won't route properly
PRI signaling troubleshooting
Publisher-Subscriber model, overview
Q.931 Translator
Registration problems on IP phone
Replication problems
Reset vs. restart
Ringback problems
Route filters, overview
SDL traces—how to read
Search for a user fails
services button doesn't work
Silence suppression—effect on voice quality
SMDI—check configuration parameters
SMDI—integration
SMDI integration with VG248
SMDI—MWI problems
SoftPhone has no lines
SoftPhone—one-way audio over VPN
SoftPhone shows line but won't go off-hook
SQL database replication problems
SQL—re-establishing a broken subscription
SQL—reinitializing a subscription
SRST and phone registration
SRST—DHCP issues
SRST—features lost during operation
SRST—phones still registered after WAN connection is restored
SRST—transfer problems
SRST—voice mail and forwarding issues
T1 CAS signaling troubleshooting
T1 interface troubleshooting
"Temporary Failure" message
Time synchronization
Toll fraud prevention
Tone on hold plays instead of music
20. Transcoder—out of resources
Transcoder—understanding codec selection between devices
Transfer problems
Transformation troubleshooting
Transformations and masks, overview
Transformations, overview
Translation pattern troubleshooting
Unity—MWI problems
Unity—TSP configuration
VAD—effect on voice quality
VG248—MWI problems
Voice mail—MWI problems (DPA 7610/7630)
Voice mail—MWI problems (SMDI)
Voice mail—MWI problems (Unity)
Voice mail—MWI problems (VG248)
Voice mail—Octel integration
Voice quality problems
WS-X6608/6624 gateway troubleshooting
WS-X6608—D-channel is down
WS-X6608—dropped calls
WS-X6608—T1 CAS problems
WS-X6608 T1/E1 configuration troubleshooting
WS-X6608—unexpected resets
WS-X6624 FXS analog gateway configuration
Chapter 1. Troubleshooting
Methodology and Approach
It's 5:30 a.m. on a Monday and your pager goes off. You recognize the phone
number— it's your CEO's administrative assistant. As the administrator of the
company's 8000-phone IP Telephony network, you assume there's a big problem.
You rush into work and find the CEO's administrative assistant, who states that
several calls for the CEO have been disconnected in the middle of the call, including
a call from a very important customer. Where do you start?
Troubleshooting a Cisco IP Telephony network can be a daunting task. Rather than
describing step-by-step how to solve specific problems (subsequent chapters provide
that information), this chapter focuses on teaching a good troubleshooting
methodology: learning how to find clues and track down your "suspect" by breaking
the problem into smaller pieces and tackling each piece individually.
A typical IP Telephony network consists of—at the very least—one or more of the
following components:
• Cisco CallManager servers
• IP phones
• Voice gateways
These components are in addition to the data network infrastructure that supports
voice over IP (VoIP) traffic. More-complex installations can have dozens of servers
for different services and redundancy, each server running a variety of applications,
as well as hundreds or thousands of IP phones and a large number of voice gateways.
21. Before exploring the myriad of tools, traces, and techniques available to you that aid
in troubleshooting, you must develop a systematic method by which you can focus
on the problem and narrow it down until you determine the root cause.
In addition to the information in this book, you should become familiar with the
various standard protocols that are used in an IP Telephony network, such as the
following:
• H.323
• Media Gateway Control Protocol (MGCP)
• Telephony Application Programming Interface/Java Telephony Application
Programming Interface (TAPI/JTAPI)
You should also become familiar with the protocols used when interfacing with the
traditional time-division multiplexing (TDM)-based Public Switched Telephone
Network (PSTN), such as the following:
• Q.931 (an ISDN protocol)
• T1- or E1-Channel Associated Signaling (T1-CAS or E1-CAS)
• Foreign Exchange Office (FXO)
• Foreign Exchange Station (FXS)
Additionally, because an IP Telephony network runs over a data network, it is
important to understand the protocols that transport VoIP data, such as the following:
• Internet Protocol (IP)
• Transmission Control Protocol (TCP)
• User Datagram Protocol (UDP)
• Real-Time Transport Protocol (RTP)
Later chapters cover some of these concepts. However, each of the mentioned
protocols could take up an entire book on its own, so you should refer to the
specifications and RFCs or to other materials that go into detail about these protocols.
Appendix A "Cisco IP Telephony Protocol and Codec Information and References,"
provides references to where you can find additional information for each protocol
discussed in this book.
On the other hand, because the Skinny Client Control Protocol (SCCP or Skinny
protocol, the Cisco-developed protocol that Cisco IP Phones use) is not the product of
an industry-wide standards body, this book goes into additional detail about how this
protocol works. Understanding the Skinny protocol is essential to understanding how
the phone operates and how to troubleshoot problems with it. The Skinny protocol is
covered in greater detail in Chapter 5, "IP Phones."
Developing a Troubleshooting Methodology or
Approach
To track down a problem and resolve it quickly, you must assume the role of
detective. First, you need to look for as many clues as you can find. Some clues lead
you to additional clues, and others lead you to a dead end. As soon as you've got all
the clues, you need to try to make sense of them and come up with a solution. This
22. book shows you where to look for these clues and track down the problem while
trying to avoid as many dead ends as possible.
Troubleshooting a problem can be broken down into two stages: data gathering and
data analysis, although your analysis might lead you to collect additional data. The
following list is a general guide for steps to take when troubleshooting an IP
Telephony problem:
Step 1. Gather data about the problem:
a. Identify and isolate the problem.
b. Use topology information to isolate the problem.
c. Gather information from the end users.
d. Determine the problem's timeframe.
Step 2. Analyze the data you collected about the problem:
a. Use deductive reasoning to narrow the list of possible causes.
b. Verify IP network integrity.
c. Determine the proper troubleshooting tool(s), and use them to find the
root cause.
Production Versus Nonproduction Outages
Troubleshooting a problem can occur in one of two timeframes:
• During a scheduled outage window, such as when you're installing a new
system, adding components, or upgrading for new features or functionality
• During production hours when the problem affects end users or service
Although the methodology to troubleshoot problems in either of these two situations
is similar, the focus on how to resolve the problem should be different. In the case of
a service-affecting problem during production hours, the focus should be to quickly
restore service by either resolving the problem or finding a suitable workaround.
In contrast, when a problem is found during a new install or scheduled outage
window, the focus should be on determining the root cause to ensure the problem is
completely diagnosed and resolved so that it does not have the potential to become
service-affecting.
For example, if users are encountering a delayed dial tone or sluggish behavior on
their phones, you might discover that a high-level process on CallManager is
consuming 100 percent of the CPU on one of the servers. During a new install or
scheduled outage window, it's a good idea to investigate what is causing the CPU
consumption to ensure that the problem does not return during production hours.
However, if this problem occurs during production hours, the best approach is to stop
or restart the offending process and let the redundant systems take over to quickly
restore service. After you restore service, perform a root-cause analysis to try to
determine why that process was consuming the CPU. The downside of this approach
is that you might not be able to further troubleshoot the problem when the process
is restarted. Fortunately, CallManager provides many diagnostic traces (if they are
enabled prior to the problem) that you can reference after a problem has occurred to
see what was happening on CallManager at the time of the problem.
Note that although 100 percent CPU of a high-level process can cause sluggish
behavior or delayed dial tone, do not infer from this that 100 percent CPU is
23. necessarily always a bad thing. As of CallManager 3.3(1), low priority tasks (such as
phone registrations) can consume 100 percent CPU without causing adverse effects
to the ability to place or receive calls. Look at the 100 percent CPU as a possible
symptom but not necessarily the root cause. In this case, you observe the symptoms
of sluggish or delayed dial tone and 100 percent CPU utilization and make a
correlation between the two.
If you encounter an event where you are unable to determine the root cause due to
insufficient information, it is a good idea to turn on the appropriate traces to ensure
that if the problem reoccurs, you will have enough data to identify the root cause.
Sometimes, several service-affecting problems occur simultaneously. In fact, this is
not uncommon, because multiple problems often manifest themselves as symptoms
of the same root cause. When multiple problems occur simultaneously, focus on the
problem that has the greatest impact on users. For example, if some users are
reporting dropped calls and others are reporting occasional echo, the two problems
are probably unrelated. Troubleshoot the dropped-call problem first because keeping
calls connected is more critical than removing the occasional echo on an active call.
Step 1: Gathering Data About the Problem
So you've just installed a new IP Telephony network, or you've been given the task
of maintaining one—or maybe you've taken your first CallManager out of the box and
are having problems getting it to run. You've encountered a problem. The first thing
to do is gather as much information about the problem as possible.
Identifying and Isolating the Problem
Half the battle in troubleshooting a problem is determining which piece of the puzzle
is the source of the problem. With so many different pieces composing an IP
Telephony network, the first step is to isolate the problem and, if multiple problems
are being reported, determine which of the problems might be related to each other
and which should be identified as separate problems.
You must also determine which parts of the problem are symptoms and which are
the root cause of the problem. For example, if a user complains of a phone resetting
itself, it might seem logical to first assume that something is wrong with the phone.
However, the problem might lie with CallManager or one of the many routers and
switches that make up the underlying data network. So although the symptom is a
phone reset, the root cause could be a WAN network outage or CallManager failure.
You must always remember to look at the big picture when searching for the root
cause and not let the symptoms of the problem lead you in the wrong direction. To
help you visualize the big picture, detailed topology information is essential.
Using Topology Information to Isolate the Problem
You can take many proactive steps to help make the troubleshooting process easier.
One of the first lines of defense is possessing current topology information. One of
the most important pieces of topology information is a detailed network diagram
(usually created using Microsoft Visio or a similar application). The network diagram
should include network addressing information and the names of all the devices. It
should also clearly show how the devices are interconnected and the port numbers
being used for these interconnections. This information will prove invaluable when
you try to isolate which components are involved in a particular problem.
24. For medium- to larger-sized networks, you should have a high-level overview
topology that gives you a general idea of how things are connected and then several
more-detailed diagrams for each piece of the network that drill down to the interface
level on your network devices.
Figure 1-1 shows a typical high-level topology diagram for a large enterprise IP
Telephony network. Notice that device names and IP addresses are listed in the
diagram. This makes troubleshooting easier by allowing you to quickly look up
devices to access them. Because Figure 1-1 is a high-level diagram, it does not get
down to the interface level of each device.
Figure 1-1. Sample High-Level Topology Diagram
Most networks are not as large as the one shown in Figure 1-1. However, no matter
the size of your network, a similar topology diagram is very useful for quickly sharing
information about your network with others who might be assisting you in
troubleshooting.
In addition to the network diagram, you should use some method to store
information such as IP address assignments, device names, password information,
and so on. For a small network, you can use something as simple as a spreadsheet
or even a plain text file. For larger deployments, some kind of database or network
management application such as CiscoWorks is recommended. Many customers keep
all this topology information on a web server as well, making it quickly and easily
accessible to others when it is needed the most. Be sure to keep this information in a
secure location.
You also need documentation of your dial plan. Some deployments, especially those
heavily utilizing toll-bypass, have very complex dial plans. Knowing where a call is
25. supposed to go just by knowing the phone number and from where it is dialed helps
you quickly understand a problem.
When your topology information is complete, it should include all the following
information:
• Interconnection information for all devices, including device names and port
numbers. If any patch panels exist between devices, the port numbers should
be listed.
• IP addressing for all network devices (routers, switches, and so on)
• IP addressing for all telephony and application servers and voice gateways
(including data application servers)
• IP addressing for endpoints (that is, scopes of a DHCP pool)
• WAN and PSTN service provider names and Circuit IDs for each circuit
• Spanning-tree topology, including root bridges for all VLANs and which ports
should be forwarding and blocking
• Dial plan information
• Software version information for all devices
If you are troubleshooting a network you didn't design, topology is one of the first
pieces of information you should obtain, if it's available. If a topology drawing is not
available, it is a good idea to spend time obtaining this information from someone
who is familiar with the network and then making a quick sketch. A general
topological understanding of the network or at least the piece of the network in
question helps when you're trying to differentiate the problem from its symptoms.
It's necessary when you're trying to isolate the problem to a particular part of the
network.
For example, if a user reports hearing choppy audio when making a conference call,
it is essential to know exactly where in the network the conference bridge device is
located in relation to the user's phone, including all the intermediate network devices.
Without a network diagram, finding this information could waste precious time.
Assume that the network you are troubleshooting looks like Figure 1-1. If the user's
phone is connected to Access Switch 1A, the other conference participants are on
Access Switch 1Z, and the conference bridge device is on Voice Switch 1A, you can
see that the number of devices is greatly reduced from 100 or more switches and
routers to four or five.
What is worse than not having topology information? Having incorrect topology
information can lead to countless hours heading down the wrong path. If you're
going to keep topology information (highly recommended), make sure you keep it
current.
Use all the topology information you have to narrow down which pieces of the
network might be involved in the problem you are trying to troubleshoot. To further
isolate the problem, interview the end users who reported the problem to gather
additional information.
Gathering Information from the User
Information the user provides can be vital to your ability to correct a problem. Try to
gather as much detail as possible on exactly what the problem is. Often when
troubleshooting a problem, you might realize that what you've been troubleshooting
for hours is not really the problem the user encountered. The more detail about the
problem you can gather before you begin troubleshooting, the easier it is to find a
26. resolution—and that means less frustration for you. Here is some general information
to collect from users:
• Details about exactly what the user experienced when the problem occurred.
• Phone numbers for all parties involved in the problematic call or calls. You can
use this as search criteria if you need to look through traces.
• Actions performed by the user when the problem occurred. This includes what
buttons were pressed and in what order.
• User observations. This includes text messages displayed on the phone or
recorded announcements.
• Information about the user's device. For example, if the user experienced a
problem while using a 7960 phone, get the phone's MAC address and IP
address, along with registration information and any other statistics available
from the phone.
Sometimes the information provided by an end user is not enough to even begin
troubleshooting. For example, if a user has trouble transferring calls, you should ask
what steps the user took when the problem happened and, if possible, when the
problem occurred so that you can examine traces. Sometimes the proper diagnostic
tools are not enabled when the problem occurs, forcing you to ask the user to inform
you the next time the problem occurs. Be sure to turn on tracing or debugs before
making the request so that when the problem occurs again, you will have captured
the data. Users can get quite irritated if you have to ask them for the same piece of
information two or three times. Also point out to the user the importance of letting
you know immediately after a problem occurs, as many of the diagnostic trace files
overwrite themselves within several hours or days (depending on the amount of
traffic on your system).
Determining the Problem's Timeframe
In addition to what the problem is, you should try to determine when the problem
occurred. Determining the problem's earliest occurrence can help correlate the
problem with other changes that might have been made to the system or other
events that occurred around the same time. For example, assume that a regular
workday begins at 9 a.m. and ends around 6 p.m. Many users report that they get a
busy signal when dialing into their voice mail. It is important to know whether they
are attempting to do this at 9:10 a.m., a time when the voice mail system is likely
under attack from many users all trying to access the system at once. This might
change the problem from a troubleshooting issue to a load-balancing or equipment-
expansion issue. You check the voice mail system and notice that at the time the
problem was reported, all the voice mail ports were in use. Clearly in this example
you need more voice mail ports or servers to handle call volume. However, if the
problem occurs at 10:30 p.m., capacity is likely not the problem, so it's time to start
troubleshooting your network and voice mail system. As another example, if a user
reports that her phone was not working for 10 minutes and you know there was a
network outage in her part of the building at that time, you can be relatively sure
that the problem was due to the network outage.
When relying on end users to give "when" information about a problem, ask them to
note the time on their phone when the problem occurred. The phone's time is
synchronized with the clock on the CallManager to which the phone is registered. As
long as you have the time on your CallManagers and network devices synchronized,
27. having a phone-based time from the user makes finding the proper trace files very
easy.
In some cases, the information about when a problem occurred might be the only
piece of information you have other than a limited description of the problem at hand.
If you have information about when, you might be able to look through trace files
during that timeframe to search for anything abnormal.
TIP
Although it is important to use information about when the problem started
happening, it is equally important to not assume that the problem was a
direct result of an event. For example, if a user reports a problem the day
after an upgrade was performed on CallManager, you might give some
credence to the notion that the upgrade might have caused the problem,
but don't automatically assume that this is the root cause.
Step 2: Analyzing the Data Collected About the Problem
Now that you have collected data from a variety of sources, you must analyze it to
find the root cause and/or workaround for your problem.
Using Deductive Reasoning to Narrow the List of Possible Causes
The next part of your fact-finding mission is to identify the various components that
might be involved and to eliminate as many components as possible. The more you
can isolate the problem, the easier it is to find the root cause. For example, if a user
complains about choppy voice quality, consider some of the following questions to
help isolate the real problem, and think about how the answer will help narrow your
focus:
• Does the problem happen on only one phone? If so, you can probably
eliminate hundreds or thousands of other phones as suspects. However, keep
in mind a single user's perspective. He might think the problem happens only
on his phone, so you'll have to ask other users to see if the problem is more
widespread than a single phone.
• What numbers are being called when the problem occurs? The answer to this
question helps determine which parts of the system are being used when the
problem occurs. For example, if the user never experiences poor audio quality
when calling certain numbers but always experiences it when calling other
numbers, this is a big clue.
• Does the problem happen only between IP phones, only through one or more
voice gateways, or both? The user probably won't know the answer, but you'll
be able to answer this question yourself after you answer the preceding
question about which numbers are being called when the problem happens.
You will find more detailed questions similar to these throughout this book when
troubleshooting particular problems.
28. Although not all of the following apply to every problem, where applicable, you must
check all of the following pieces involved in the call. Use your topology information to
help obtain this information.
• CallManager nodes involved in the signaling
• Network devices that signaling and/or voice traffic traverse
• Gateways or phones involved in the call
• Other devices involved, such as conference bridges or transcoders
Concentrate your energy on the smallest subset of devices possible. For example, if
all the users on a particular floor are having the same problem, concentrate on the
problem a particular user is having. If you fix the problem for that one user, in most
cases you fix it for all the affected users.
Verifying IP Network Integrity
One thing that people often forget is that your IP Telephony network is only as good
as your IP network. A degraded network or a network outage can cause a wide range
of problems, ranging from slight voice quality problems to a total inability to make or
receive calls on one or more phones. The network is always a consideration when
you encounter certain problems, so network health issues are covered throughout
this book. Network health is especially important during the discussion of voice
quality problems in Chapter 7, "Voice Quality," because most voice quality problems
stem from packet delay and/or loss.
Always remember to keep the IP network in mind and look at every layer in the OSI
model, starting from Layer 1. Check your physical layer connectivity (cables, patch
panels, fiber connectors, and so on). Then make sure you have Layer 2 connectivity
by checking for errors on ports, ensuring that Layer 2 switches are functioning
properly, and so forth. Continue working your way up the stack until you reach the
application layer (Layer 7). As an example, two of the most common reasons for
one-way audio (where one side of the conversation cannot hear the other) are the
lack of an IP route from one phone to another and the lack of a default gateway
being configured on a phone. Taking the layered approach, you would first check the
cabling and switches to make sure that there are no errors on the ports. You would
then check Layer 3, the network layer, by ensuring that IP routing is working
correctly. When you reach this layer, you discover that for some reason the IP
packets from one phone are unable to reach the other phone. Upon further
investigation, you might discover that there was a missing IP route on one of the
routers in the network or a missing default gateway on one of the end devices (such
as an IP phone or voice gateway).
Determining the Proper Troubleshooting Tool
After you narrow down the appropriate component(s) causing a problem and have
detailed information from the user(s) experiencing the problem, you must select the
proper tool(s) to troubleshoot the problem. Most components have multiple
troubleshooting tools available to help you. Chapter 3, "Understanding the
Troubleshooting Tools," provides more details about some of the tools available for
troubleshooting CallManager. You should use the tracing and debugging facilities
available in CallManager and other devices to determine exactly what is happening.
Additional tools and traces are covered in the chapter associated with diagnosing
certain types of problems. For example, Chapter 6, "Voice Gateways," covers
29. debugging Cisco IOS Software voice gateways. Because CallManager is central to
almost all problems, information about various portions of the CCM trace facilities
appears throughout this book.
This step is the most demanding on your troubleshooting skills because you analyze
the detailed information provided in the various tools and use it to search for
additional clues using other tools. Sometimes the problem description you have is
not detailed enough to determine which tool to use. In this case, you should try
various tools in search of anything that looks out of the ordinary.
The following case study shows how this troubleshooting methodology works in a
real-world scenario.
Case Study: Resolving a Problem Using Proper
Troubleshooting Methodology
It is 6 a.m., and you have arrived at work to resolve your CEO's problem. The only
data you have is the page you received at 5:30 a.m. that says "CEO's calls keep
dropping. Please help ASAP!" You need a bit more information than that to fix the
problem.
This case study applies the methodology previously described. You must gather the
data before you can begin the analysis.
Gathering the Data
As part of the data-gathering stage, you should do the following:
• Identify and isolate the problem
• Use topology information to isolate the problem
• Gather data from the end users
• Determine the problem's timeframe
You find the CEO's administrative assistant and begin your fact-finding mission. He
states that at various times during the previous day and one time this morning, the
CEO is on the phone when, all of the sudden, the call is disconnected. Eager to
resolve the problem, you ask the administrative assistant for the following
information:
• The exact date and times the problem occurred
• Whether the dropped calls were incoming or outgoing
• What number was dialed if it was an outbound call or what number the call
came from if it was an inbound call
The assistant states that the call was dropped around 5:15 a.m. because the CEO
was in early to prepare for the stockholders meeting. This is the extent of the
information he remembers. Most users do not pay attention to specifics like this
unless they have been instructed to, but all is not lost. The CEO has a 7960 phone
that stores information locally about missed calls, received calls, and placed calls.
You head into the CEO's office and look at the list of received calls and placed calls
for the morning. You notice that a call was received at 5:05 a.m. and a call placed at
5:25 a.m. You notice that the second call was placed to the same area code and
prefix as the call that was received.
30. You ask the CEO about the two calls. She remembers that she was on the phone
with a customer for about 15 minutes when the call was disconnected. She
immediately called the customer back. She also confirms that the first call that was
received was the dropped call. Now you know that the problematic call was received
at approximately 5:05 a.m. and was dropped just before 5:25 a.m.
While you are looking at the CEO's phone, you also go into the Settings menu (press
the settings button > Network Configuration > CallManager 1) to see which
CallManager the CEO's phone is registered to. This lets you isolate which
CallManager in the cluster is involved in the signaling for this phone.
Armed with this information, you can begin the task of isolating the problem. You
refer to your topology diagram to isolate the components that are involved. Figure 1-
2 shows a high-level diagram of the network topology.
Figure 1-2. High-Level Topology Diagram
Reinforcing the topology in Figure 1-2, assume the following setup:
• A cluster with eight CallManager nodes
• 32 voice gateway connections to the PSTN for outgoing calls at your main
site—16 for local calls and 16 for international and long distance
• 32 more voice gateways at your main campus where all your inbound calls
come in. The telephone company has set up the inbound calls so that the 32
gateways are redundant whereby if one of the gateways is down, all your
incoming calls can still use any of the other remaining gateways.
• Two gateways at each remote site used for both inbound and outbound calls.
All outbound calls prefer the first gateway, and inbound calls prefer the
31. second gateway, although each can handle both inbound and outbound calls
should one fail.
As shown in Figure 1-2, the executive offices are at a remote site across the WAN.
With just the information you have so far, you can eliminate a large portion of the
network. So far you know that the problematic call was to the CEO. You also know
that the problematic call was an inbound call. You ask the CEO and her admin if all
the dropped calls were inbound calls. As far as they can remember, they were.
You know that the call this morning was during a time of day where there is little
phone activity. Remember that all inbound calls to the remote site come in through
Primary Rate Interfaces (PRIs) connected to the remote voice gateways and that
inbound calls to the site prefer the second gateway. It is unlikely that all the
channels on the first PRI were in use during a time of low call volume, so you
assume that the call probably came in through the second gateway, although you
still keep it in the back of your mind that the call might have come in through the
first gateway at the remote site.
You then look at the configuration for the two gateways at Remote Site 2 and note
that they are both configured to send incoming calls to CallManager Subscriber 3 as
their preferred CallManager and CallManager Backup 1 in case CallManager
Subscriber 3 fails.
With the information you have so far, you can narrow down the possible suspect
devices to the network shown in Figure 1-3.
Figure 1-3. Network After You Narrow Down the Possible
Suspects
32. Armed with this knowledge, you can immediately isolate the problem to the user's
phone and the two gateways being used for inbound calls. Keep in mind that you
haven't eliminated the possibility that the problem is on CallManager or is network-
related.
Now that you know the problem is related to inbound calls, it makes sense to try to
understand the call flow for an inbound call to this user. Determine whether these
calls all come directly to the user or if the call flow has any intermediate steps, such
as Cisco IP Auto Attendant (Cisco IP AA) or an operator who transfers the call to the
end user. For the sake of this example, assume that the user has a Direct Inward
Dialing (DID) number, so the call comes straight from the PSTN through a gateway
to the user, and a Cisco IP AA or operator is not involved. You have now eliminated
Cisco IP AA from the picture, as well as the possibility that other phones or users are
involved in this user's problems. This is not to say that other users are not
experiencing similar problems, but the focus here is on solving this particular user's
problem. If the problem is more widespread than this one user, you will probably
find it as you continue to troubleshoot this user's problem.
At this point, the problem has been isolated to the following culprits:
• The CEO's phone
33. • CallManager Subscriber 3
• Site 2 Router/GW 1 and Site 2 Router/GW 2
• The underlying network connecting these devices
It might seem like you haven't made much progress in this example, but in reality
you have eliminated a large portion of the system as possible culprits. This concludes
the data-gathering piece of your investigation. Now it is time to start analyzing the
data. After you isolate the problem, you must break it into smaller pieces.
Analyzing the Data
As soon as you have a clear understanding of the problem you're trying to resolve,
and you have isolated the piece or pieces of the network that are involved, the next
step is to break the problem into pieces to find the root cause. As part of the data
analysis stage, you should do the following:
• Use deductive reasoning to narrow the list of possible causes
• Verify IP network integrity
• Determine the proper troubleshooting tools, and use them to find the root
cause
Continuing with the case study example, you now know the pieces involved in the
puzzle, but you still don't know why the call is being dropped. For the sake of this
example, this chapter keeps things general, but later chapters go into far greater
detail on exactly what to look for. In this case, the problem is likely caused by the
phone, CallManager, the gateway, the PSTN, or the IP network. So how do you
determine which one is causing the problem?
One important distinction to make that will become evident as you read through this
book is that many problems can be narrowed down to being either signaling-related
or voice packet-related. In this case, you are dealing with a signaling-related
problem, because the problematic call is being torn down—a problem that must
occur in the signaling path between devices.
Because nearly all signaling for a call must go through one or more CallManager
servers, the first tool you decide to use is a trace from CallManager Subscriber 3.
You can then analyze the trace files to discover the device that disconnects the call
from CallManager's perspective—in other words, "Who hung up first?" Using the
information provided by the user, you must find the proper trace file and try to
reconstruct the call from beginning to end.
A call between the CEO's phone and the voice gateway has two distinct signaling
connections. One is the communication between CallManager and the voice gateway.
The other is the communication between CallManager and the phone. The phone and
voice gateway never directly exchange signaling data. All signaling goes through
CallManager.
The trace includes all the messaging between CallManager and both the phone and
the gateway. Chapter 3 provides more details on where to find these traces and how
to read them.
You know that the call in question was set up around 5:05 a.m., so you look through
the traces during that timeframe, searching for the phone number you retrieved
from the CEO's phone. After combing through the trace file, you determine that the
gateway is sending a message to CallManager, telling it to disconnect the call. The
CCM traces (discussed in Chapter 3) indicate which gateway the calls are coming
from. This eliminates the CEO's phone as a cause of the problem because the
34. disconnect message is coming from the gateway. Because the user indicated that
there were three drops, you can now go through the same process of looking
through the CCM trace files for each instance of a dropped call and reconstructing
those calls to see if the problem is isolated to one gateway. If you don't know the
times that the other calls were dropped, you should just concentrate on the one call
you do have data for.
Because CallManager received a message from the gateway telling it to disconnect
the call, it is unlikely that a network problem is causing the calls to disconnect. If
there were a network problem, you would likely see an indication that there was a
problem communicating between CallManager and the gateway. In this case, the
gateway had no problem sending the disconnect message to CallManager. It would
not hurt to look through the network devices between CallManager and the voice
gateway to ensure that there are no network errors, but with a problem like this, the
network is an unlikely culprit.
At this point, you have narrowed down the problem to be originating from either the
voice gateway or the PSTN. Figure 1-4 shows you've narrowed down the network to
only a few devices.
Figure 1-4. Network After You Continue Narrowing Down the
Possible Suspects
The next step is to go to the suspected gateway and try to determine why one of the
calls was dropped. This involves turning on additional debugs on the gateway to
determine if the gateway is disconnecting the call or just passing along information
35. from the PSTN about disconnecting the call. Unfortunately, it is unlikely that you had
the debugs enabled at the time the problem occurred, so you need to enable the
proper debugs and wait for the problem to happen again. This is why it is so
important to narrow down the problem to a small subset of devices: You do not want
to turn on debugs on dozens of gateways.
Which debugs to use depends on the gateway model and the type of interface to the
PSTN. Chapter 6 discusses these considerations in detail. While waiting for the
problem to reoccur, you discover that a message to disconnect the call is coming
from the PSTN. If you are using an ISDN voice circuit for connectivity to the PSTN,
the disconnect message is accompanied by a cause code that provides a general
reason why the call was disconnected. Depending on what you discover on the
gateway debugs, the next step might be to contact the local service provider or
perhaps debug the gateway further to find the root cause.
Conclusions
As this case study has demonstrated, the more information you can obtain about the
problem, the easier it is to get to the root cause. For example, without the times the
dropped calls occurred, it would have been almost impossible to find them in the
trace files on a busy system. When deployed in a large enterprise, it is good to arm
your help desk with a list of questions to ask depending on the problem being
reported.
The point of this example is not to teach you how to troubleshoot a specific problem
or to find out exactly why the user's calls are being dropped. It is to show you how
to approach a problem in order to isolate it and break it into more manageable
pieces. The same principles can be applied to almost any problem you are
troubleshooting.
So remember, first put on your detective hat and gather enough information to
isolate the problem to a few pieces of the system. Then dig deeper into each
component by breaking the problem into more manageable pieces. Finally, apply
your expertise to each of the smaller pieces until you find the resolution to your
problem.
Summary
This chapter discussed the methodology you should employ to successfully
troubleshoot problems in an IP Telephony network. You should become familiar with
the methodologies discussed here. It is vital that you always follow a consistent
approach to troubleshooting. Many basic problems can be avoided by using a
consistent troubleshooting approach.
Also, be sure that you understand the big picture of IP Telephony architecture. What
areas are you unsure about? Are you strong in IP but weak in call processing skills?
Are you familiar with the basic protocols that are used? Consider where you are now,
and as you move forward, pay particular attention to strengthening your weak areas.
As you begin this journey, hopefully this book can bring some illumination to the
sometimes daunting task of troubleshooting an IP Telephony network.
Chapter 2. IP Telephony Architecture
Overview
36. Cisco AVVID (Architecture for Voice, Video and Integrated Data) includes many
different components that come together to form a comprehensive architecture for
voice, video, and integrated data.
This chapter covers the basic components of the IP Telephony architecture in order
to get a big-picture viewpoint of the system. With this overview as the starting point,
the ensuing chapters address each of these components.
Cisco AVVID IP Telephony can be characterized as having three primary layers:
• Network infrastructure
• IP Telephony infrastructure
• Applications
Network Infrastructure
The network infrastructure is a key piece of the IP Telephony architecture. The
infrastructure includes switches and routers, and it connects local-area networks
(LANs), metropolitan-area networks (MANs), and wide-area networks (WANs). Your
network design must be built for high availability, and the Cisco series of switches
and routers provides that capability. A voice-enabled network is a quality of service
(QoS)-enabled network that gives precedence to voice, call signaling, and data to
ensure good voice quality and rapid call signaling.
IP Telephony Infrastructure
The IP Telephony infrastructure includes the Cisco CallManager call processing
engine and the various endpoints that carry voice. This includes client endpoints and
various voice gateways that are interfaces to the Public Switched Telephone Network
(PSTN).
Call Processing
The CallManager software is the heart of Cisco AVVID IP Telephony that provides call
processing features and capabilities to network devices in the enterprise. IP phones,
voice gateways, media processing devices, and multimedia applications are just
some of the network devices for which CallManager provides call processing.
CallManager is installed on the Cisco Media Convergence server and other approved
IBM and Compaq servers. CallManager is shipped with integrated voice applications
and utilities such as Cisco CallManager Attendant Console (formerly Cisco
WebAttendant), software conferencing, and the Bulk Administration Tool (BAT).
Multiple CallManager servers are clustered and managed as a single entity.
CallManager clustering yields scalability of up to 36,000 users per cluster with
version 3.3. By interlinking multiple clusters, system capacity can be increased up to
one million users in a 100-site system. Triple call processing server redundancy
improves overall system availability.
The benefit of this distributed architecture is improved system availability and
scalability. Call admission control ensures that voice QoS is maintained across
constricted WAN links and automatically diverts calls to alternative PSTN routes when
WAN bandwidth is unavailable.
37. The four primary call processing models that are used to meet the needs of the
enterprise are
• Single-site deployment model
• Multiple-site deployment model
• Centralized deployment model
• Distributed deployment model
Single-Site Deployment Model
In this deployment model, CallManager, applications, voice mail, and digital signal
processor (DSP) resources are located at the same physical location. Figure 2-1
shows an example of these components located at a single site.
Figure 2-1. Single-Site Deployment Model
Multiple-Site Deployment Model
In this deployment model, CallManager, applications, voice mail, and DSP resources
are located at one physical location. Multiple sites exist, and they connect to each
other via the PSTN. Figure 2-2 shows an example of each separate site connecting
via the PSTN.
Figure 2-2. Multiple-Site Deployment Model
38. Centralized Deployment Model
A centralized call processing deployment model centrally locates CallManager,
applications, voice mail, and DSP resources while many remote locations connect to
the central site for all these services. Locations-based call admission control prevents
over-subscription of the WAN. At each remote site, Survivable Remote Site
Telephony (SRST) ensures that call processing continues in the event of a WAN
outage. The centralized call processing model is really the same as the single-site
deployment model with the addition of remote sites across the WAN. Figure 2-3
illustrates the centralized deployment model.
Figure 2-3. Centralized Deployment Model
39. Distributed Deployment Model
In a distributed deployment model, CallManager and applications are located at each
site with up to 36,000 IP phones per cluster. One hundred or more sites could be
interconnected via H.323 using a gatekeeper for call admission control and dial plan
resolution. Transparent use of the PSTN is available if the WAN is down. Figure 2-4
depicts a distributed deployment model.
Figure 2-4. Distributed Deployment Model
40. Cisco AVVID IP Telephony Infrastructure
The Cisco AVVID IP Telephony infrastructure includes Cisco Media Convergence
Servers and other certified servers running CallManager, Cisco Unity, or other
applications, such as IP Auto Attendant, IP Interactive Voice Response (IVR), and IP
Integrated Contact Distribution (ICD). Switches, routers, and voice gateways are all
part of this infrastructure as well. Although infrastructure is not the primary focus of
this book, it is an important part of the IP Telephony architecture, and you will see
discussion of some infrastructure aspects when dealing with a Cisco AVVID IP
Telephony deployment.
Clients
41. Clients consist primarily of IP phones. Cisco offers several models with different
functions, and these are deployed throughout the IP Telephony infrastructure.
Additionally, several third-party companies throughout the world have developed IP
phones for their markets. Figure 2-5 shows the Cisco family of IP Phones.
Figure 2-5. Cisco Family of IP Phones
Table 2-1 provides highlights of each phone and its features.
Table 2-1. Descriptions of IP Phone Models
Phone Model Description
Cisco IP Phone
7960
A full-featured, six-line business set that supports the following
features:
• A help (i or ?) button
• Six programmable line or speed dial buttons
• Four fixed buttons for accessing voice mail messages,
adjusting phone settings, and working with services and
directories
• Four soft keys for displaying additional call functionality,
such as hold, transfer, conference, and so on
• A large liquid crystal display (LCD) that shows call detail
and soft key functions
42. Table 2-1. Descriptions of IP Phone Models
Phone Model Description
• An internal two-way speakerphone and microphone mute
Cisco IP Phone
7940
A full-featured, two-line business set with all the same features
as the Cisco IP Phone model 7960, except only two lines.
Cisco IP Phone
7914 Expansion
Module
An expansion module for the Cisco IP Phone 7960 that provides
14 additional line or speed dial buttons. It has the following
features:
• An LCD to identify the function of the button and the line
status
• The capability to daisy-chain two Cisco IP Phone 7914
Expansion Modules to provide 28 additional line or speed
dial buttons for a total of 34 line or speed dial buttons
Cisco IP Phone
7910/7910+SW
A single-line, basic feature phone designed primarily for
common-use areas with medium telephone traffic, such as
lobbies or break rooms. It includes the following features:
• Four dedicated feature buttons for Line, Hold, Transfer,
and Settings
• Six programmable feature buttons that you can
configure through phone button templates in Cisco
CallManager Administration. Available features include
call park, redial, speed dial, call pickup, conference,
forward all, group call pickup, message waiting, and
Meet-Me conference
• A two-line LCD (24 characters per line) that indicates the
directory number, call status, date, and time
• An internal speaker designed to be used for hands-free
dialing
• A handset cord jack that can also be used for a headset
• (7910+SW only) A Cisco two-port switch with
10/100BaseT interface
Cisco IP Conference
Station 7935
A full-featured, IP-based, full-duplex, hands-free conference
station for use on desktops, in offices, and in small- to-medium-
sized conference rooms. It includes the following features:
• Three soft keys and menu navigation keys that guide a
user through call features and functions. Available
features include call park, call pickup, group call pickup,
transfer, conference, and Meet-Me conference
• An LCD that indicates the date and time, calling party
name, calling party number, digits dialed, and feature
and line status
• A digitally-tuned speaker and three microphones
43. Table 2-1. Descriptions of IP Phone Models
Phone Model Description
allowing conference participants to move around while
speaking
• Microphone mute
Cisco IP Phone Models 7960 and 7940
The 7960/7940 phones are the most common clients in a Cisco IP Telephony
network. These phones feature a large pixel-based display that allows for XML-based
applications on the phone. Because these phones are largely soft key-based, new
features can easily be added via software upgrades instead of requiring the purchase
of new hardware.
The internal three-port Ethernet switch allows for a direct connection to a
10/100BaseT Ethernet network via an RJ-45 interface with single LAN connectivity
for both the phone and a co-located PC. The system administrator can designate
separate VLANs (802.1Q) for the PC and Cisco IP Phone. The 7960/7940 phones can
also receive power down the line from any of the Cisco inline power-capable switches
or the Cisco inline power patch panel.
A dedicated headset port eliminates the need for a separate, external amplifier when
you use a headset, consequently reducing desk clutter. The 7960/7940 phones
feature a high-quality, full-duplex speakerphone, as well as a speaker on/off button
and microphone mute buttons.
Cisco IP Phone Expansion Module 7914
The Cisco IP Phone Expansion Module 7914 extends the capabilities of the Cisco IP
Phone 7960 with additional buttons and an LCD. The Expansion Module lets you add
14 buttons to the existing six buttons on the 7960 phone, increasing the total
number of buttons to 20 with one module or 34 when you add two 7914s. Up to two
Cisco 7914s can be connected to a 7960.
The 14 buttons on each 7914 Expansion Module can be programmed as directory
numbers or speed dial buttons, just like the 7960. Multicolor button illumination
allows you to identify which lines are ringing, on hold, or in use.
Cisco IP Phone 7910
This low-end phone features on-hook dialing and call monitor mode but does not
include speakerphone capability. The phone provides a mute button for the handset
and headset microphones. You can attach a headset by removing the handset and
using the port into which the handset cord was attached.
The 7910 plugs into a standard RJ-45 Ethernet connection. A second version of the
7910 phone, the 7910+SW, provides a Cisco two-port switch with a 10/100BaseT
interface. The 7910+SW phone model provides a single RJ-45 connection at the
desktop for the phone and an additional LAN device, such as a PC.
The 7910 phones can also receive power down the line from any of the Cisco inline
power-capable switches or the Cisco inline power patch panel.
44. Cisco IP Conference Station 7935
The Cisco IP Conference Station 7935 is a conference room speakerphone utilizing
speakerphone technologies from Polycom with the Cisco AVVID voice communication
technologies. The 7935 is an IP-based, full-duplex, hands-free conference station for
use on desktops and offices and in small- to-medium-sized conference rooms.
Although the 7935 does not accept inline power from a Cisco inline power-capable
switch, it does feature a power interface module (PIM) that provides power interface
and network connectivity.
Voice Gateways
Many Cisco voice gateways are available for use in the IP Telephony network. These
gateways interoperate with CallManager using various protocols. They interface with
the PSTN using different TDM-based protocols such as T1/E1-PRI, T1-CAS, FXO, FXS,
and so on.
One of the primary protocols used by Cisco voice gateways is MGCP. Gateways that
support MGCP as of CallManager Release 3.1 include the following:
• Cisco VG200
• Cisco 3700, 3600 and 2600
• Cisco Catalyst 6000 E1/T1 Voice and Service modules
• Cisco Catalyst 4000 Access Gateway Module
• Cisco DE-30+
• Cisco DE-24+
When MGCP is used, CallManager controls routing and tones and provides
supplementary services to the gateway. MGCP provides the following services:
• Call preservation (calls are maintained during switchover to a backup
CallManager and switch back to the primary CallManager)
• Redundancy
• Dial plan simplification (no dial-peer configuration is required on the gateway)
• Hookflash transfer
• Tone/music on hold
MGCP-controlled gateways do not require a media termination point (MTP) to enable
supplementary services such as hold, transfer, call pickup, and call park.
H.323 is another protocol used by Cisco voice gateways. Cisco IOS Software
integrated router gateways can also use the H.323 protocol to communicate with
CallManager. Intercluster trunks for connecting remote CallManagers across the IP
WAN are also configured as H.323 gateways. Compared to MGCP, H.323 requires
more configuration on the gateway because the gateway must maintain the dial plan
and route patterns.
Two gateways, the VG248 and the ATA-186, use the Skinny Client Control Protocol
(SCCP or Skinny protocol), the same protocol used by IP phones, to communicate
with CallManager. Each port on these gateways registers individually as a phone
device, so from the CallManager perspective, it does not treat the gateway as a
single entity but rather treats each port the same way it treats an IP phone. Using
Skinny on these gateways allows the gateway to provide features such as message
waiting indicators (MWI), conferencing, and transfer to non-IP phones that would not
be possible using any of the other supported protocols.
45. Finally, some older Cisco voice gateways use the Skinny Gateway Control Protocol
(SGCP), such as the Cisco Analog Access AT-2, AT-4, AT-8, AS-2, AS-4, and AS-8.
Cisco AVVID IP Telephony Applications
The following list describes some voice and video applications in the application layer
of Cisco AVVID IP Telephony:
• Cisco Unity— A messaging application that provides voice and/or unified
messaging to enterprise communications.
• Video IP/TV and IP videoconferencing products— Applications that
enable distance learning and workgroup collaboration.
• Cisco IP IVR— An IP-powered interactive voice response (IVR) solution, the
IP IVR, combined with Cisco IP Auto Attendant, provides an open and feature-
rich foundation for delivering IVR solutions over an IP network. Cisco IP IVR
and IP AA are built on the Cisco Customer Response Applications (CRA)
platform.
• Cisco IP ICD— An automatic call distributor (ACD) for enterprise
organizations. Cisco IP ICD is built on the Cisco Customer Response
Applications (CRA) platform.
• Cisco CallManager Attendant Console— A flexible and scalable application
that replaces the traditional PBX manual attendant console.
• Cisco IP SoftPhone— A software computer-based phone for Windows 98,
Windows NT, Windows 2000, and Windows XP that provides communication
capabilities that increase efficiency and promote collaboration.
• Personal Assistant— A software application that selectively handles calls
and helps you make outgoing calls. Personal Assistant provides rule-based
call routing, speech-enabled directory dialing, voice mail browsing, and simple
Ad Hoc conferencing.
• Cisco Conference Connection— A Meet-Me audio conference server that
provides integrated operation with CallManager.
• Cisco Emergency Responder— An application that allows emergency
agencies to identify the location of 911 callers and eliminates the need for any
administration when phones or people move from one location to another.
Cisco ER features a real-time location-tracking database and improved routing
capabilities to direct emergency calls to the appropriate Public Safety
Answering Point (PSAP) based on the caller's location.
Summary
This chapter provided an overview of the primary components that are involved in
the Cisco IP Telephony architecture, including the deployment models, clients, voice
gateways, and Cisco AVVID IP Telephony applications. When troubleshooting, it is
important that you have the big picture of all the architecture components to
implement the troubleshooting methodology covered in Chapter 1, "Troubleshooting
Methodology and Approach."
46. Chapter 3. Understanding the
Troubleshooting Tools
To effectively troubleshoot problems in a Cisco IP Telephony (CIPT) network, you
must be familiar with the many tools at your disposal. In addition, you need to know
how best to use those tools to achieve maximum results. This chapter describes the
various tools and their different uses.
Depending on the problem you encounter and your particular skill set, you might find
certain tools more helpful than others. Nevertheless, knowing what tools are
available and how they can help you solve the problem is essential to a successful
resolution. Also, some tools might be more useful to you based on your past
experience. If you are strong in IP, a sniffer trace might be your preferred tool when
applicable. However, if you are stronger in call processing-related traces, the Cisco
CallManager (CCM, also sometimes called SDI) traces might prove helpful once you
understand how they work.
Later chapters demonstrate the use of these tools in different scenarios you might
encounter.
This chapter covers the following topics:
• Time synchronization— Explains how to synchronize the clocks on all
devices in an IP telephony network to ensure that timestamps on your trace
files and debugs are synchronized with each other.
• Reading CCM (or SDI) traces— Describes one of the most important trace
files you use to troubleshoot CallManager-related problems. CCM trace files
provide information about call processing events and all messages exchanged
between Skinny, MGCP, and H.323 endpoints.
• Reading SDL traces— Discusses the components of the less-used Signal
Distribution Layer (SDL) trace files in CallManager. SDL traces describe the
events occurring in the CallManager software at a code level. These traces are
usually reserved for Cisco development engineering use; however, there are a
few key pieces of information you can use to your advantage when
troubleshooting CallManager problems.
• Microsoft Performance (PerfMon)— Details the capabilities of PerfMon, a
built-in Windows 2000 utility that helps you troubleshoot CallManager.
• CCEmail— Details the third-party alerting tool that can be used in
conjunction with PerfMon to configure alerts for the performance counters.
• CallManager Serviceability— Discusses various web-enabled tools provided
with CallManager for reading alarms and XML-based tracing.
• Real Time Monitoring Tool (RTMT)— Describes the Cisco web-based
monitoring application that allows you to view CallManager cluster details,
monitor performance objects (much like PerfMon), and monitor devices and
CTI applications.
• Call detail records (CDR) and the CDR Analysis and Reporting (CAR)
Tool— Describes the CAR tool that helps you analyze the raw data that
comprises the CDR database and create reports based on your search criteria.
• CDR Time Converter— Describes how to use this small utility that allows
you to convert the UNIX Epoch-based date and time format stored in a CDR
to standard date and time format.
• Event Viewer— Briefly explains the function of another built-in Windows
2000 tool that plays a key role in troubleshooting CallManager.
47. • Q.931 Translator and Enhanced Q.931 Translator— Describes two tools
that read a CCM trace file and analyze all Q.931 and H.225 messages. The
various information elements are decoded for ease of reading. The Enhanced
Q.931 Translator also adds additional search and filtering options and decodes
more information elements than the original Q.931 Translator.
• Dick Tracy— Describes an important tool used to troubleshoot the WS-X6608
and WS-X6624 voice gateways for the Catalyst 6000 series switches.
• Sniffer traces— Discusses when and why to use a network packet-capture
tool.
• Voice Codec Bandwidth Calculator— Describes how to use the Voice
Codec Bandwidth Calculator to determine the bandwidth used by different
codecs with various voice protocols over different media.
• Cisco Bug Toolkit (formerly Bug Navigator)— Describes the web-based
tool that allows you to find known bugs based on software version, feature
set, and keywords. The resulting matrix shows when each bug was integrated
or fixed if applicable.
• Remote Access Tools— Describes applications like Terminal Services and
Virtual Network Computing, which allow you to access a server from a remote
location.
• Websites and Further Reading— Provides URLs for websites that contain
additional troubleshooting information. Also points you to a section in the
"Introduction" with a recommended reading list.
Time Synchronization
Time synchronization is simply making sure that all the participating CallManager
servers and network devices have the same exact time. Time synchronization is
critical. A large CallManager cluster can have eight or more separate servers, not
including any voice mail servers or application servers. This distributed architecture
creates a highly available and scalable system. It also makes the troubleshooting
process more involved because you have to collect traces from all participating
servers to see the full picture of what happened.
As endpoints such as IP phones and voice gateways call each other, signaling occurs
between CallManager and the endpoint device. Signaling also occurs between the
respective CallManagers of each endpoint device. If a problem occurs, you need to
consolidate trace files from all involved servers. CallManager Serviceability, discussed
later in this chapter, can collect this information into one file. However, if the
timestamps of each file are mismatched, it can be impossible to tell what the real
series of call processing events is.
All the CallManager servers can be time-synched using the Network Time Protocol
(NTP). When you synchronize the time on all involved servers, all the trace files are
timestamped the same. When trace files are collected for analysis, you can follow the
true series of call processing events with accuracy.
In addition to CallManager servers, you should ensure all network devices such as
switches, routers, and voice gateways are synchronized to the same time source as
the CallManager servers. This ensures consistent timestamps regardless of which
device you are looking at.
Configuring Automatic Time Synchronization on CallManager
Servers
48. Use the following steps to configure the CallManager server to automatically
synchronize—and stay synchronized—with a Time Server.
Step 1. Verify that the NetworkTimeProtocol service is configured to launch
automatically upon startup. Right-click My Computer and select Manage.
Step 2. Expand the Services and Applications section, and select Services.
Step 3. Double-click the NetworkTimeProtocol service, and ensure that
Startup Type is set to Automatic.
Step 4. Configure the C:WINNTntp.conf file. This file contains the list of
time servers that CallManager will synchronize with. You can configure
CallManager to point to specific time servers (see Example 3-1), or you can
configure it to receive NTP broadcasts (see Example 3-2) on the local LAN
segment from the router (as long as the router is configured to do so).
Example 3-1. Sample ntp.conf File Using Static Time
Servers
server 10.0.0.10
server 10.1.0.10
driftfile %windir%ntp.drift
Example 3-2. Sample ntp.conf File Using an NTP Broadcast
Router
broadcastclient
driftfile %windir%ntp.drift
Step 5. Go to the Services Control Panel and stop/start the
NetworkTimeProtocol service. Allow several minutes for the update to take
place.
Synchronizing Time Manually on CallManager Servers
Use the following steps to manually configure time synchronization.
Step 1. Stop the NetworkTimeProtocol service in the Services Control Panel.
Step 2. Synchronize the clock by using one of the following commands from
a command prompt.
To synchronize with a remote Time Server, use the following command where
x.x.x.x is the IP address of the Time Server:
ntpdate x.x.x.x
To synchronize with a Broadcast Router, use the command where x.x.x.x is
the IP address of the Ethernet port of the router:
49. ntpdate x.x.x.x
Step 3. Restart the NetworkTimeProtocol service in the Services Control
Panel.
Synchronizing Time on Cisco IOS Devices
In addition to your CallManager servers, you should also ensure the time is
synchronized on all your network devices, including IOS voice gateways, switches,
and routers.
For Cisco IOS devices, you can use the Network Time Protocol (NTP) to synchronize
the time. To enable NTP, you must configure the time zone the IOS device is in along
with the IP address of the NTP server. You should configure the IOS device to take
daylight savings time into account as well if you live in a time zone that observes
daylight savings time.
First you must configure the time zone. Use the command clock timezone
name_of_time_zone offset_from_GMT to configure the time zone. For example, the
following command configures the IOS device for Eastern Standard Time (EST):
clock timezone EST -5
If you are in a time zone that observes daylight savings time, use the command
clock summer-time name_of_time_zone recurring to enable automatic daylight
savings time. For example, the following configures Eastern Daylight Savings Time:
clock summer-time EDT recurring
You can determine time zones by performing a search at Google.com; search for a
string such as "time zone GMT." Any one of the many hits should point you to a table
showing the various time zones around the world, including daylight savings time.
Once your time zone is configured properly, you can enable NTP. If you do not have
a device on the network running NTP, you can make an IOS device into an NTP
master clock. You can do this by configuring the command ntp master on the IOS
device. If you are not making the device an NTP master, you should configure the IP
address of the NTP server using the command ntp server NTP_server_IP_address.
For example, the following tells the IOS device to synchronize its clock with the NTP
server at IP address 172.18.109.1:
ntp server 172.18.109.1
Once you have enabled NTP, all IOS devices should synchronize their clocks with the
central NTP server. You should also synchronize the clocks on non-IOS network
devices such as switches running CatOS software.
Synchronizing Time on CatOS Devices
50. You can use NTP to synchronize the clocks on switches running CatOS software. The
configuration is similar to configuring NTP on a device running Cisco IOS Software.
First you must configure the time zone the switch is in using the command set
timezone name_of_time_zone offset_from_GMT. For example, the following sets
the clock to Eastern Standard Time:
set timezone EST -5
You can also configure daylight savings time using the command set summertime
enable name_of_time_zone. For example, the following enables Eastern Daylight
Savings Time:
set summertime enable EDT
You can determine time zones by performing a search at Google.com; search for a
string such as "time zone GMT." Any one of the many hits should point you to a table
showing the various time zones around the world, including daylight savings time.
Once you have the time zone configured properly, you can set the NTP server IP
address and enable the NTP client on the switch. First set the NTP server IP address
using the command set ntp server NTP_server_IP_address. Then enable the NTP
client using the command set ntp client enable. The following shows the
configuration to use the NTP server with IP address 172.18.109.1:
set ntp server 172.18.109.1
set ntp client enable
Once you have enabled proper time synchronization in your network, you can move
on to reading the variety of trace files available to you for troubleshooting problems
in an IP Telephony network.
Reading CCM (or SDI) Traces
CCM (also known as System Diagnostic Interface or SDI) traces are the user-
friendliest call processing trace files you have available to you. After you learn a few
tricks, it is easy to follow the call flows and find the potential problem. Although you
might see "SDI" and "CCM" used interchangeably to refer to this type of trace, in this
book we primarily refer to this type of trace as a CCM trace. Some pages in
CallManager Serviceability refer to CCM traces as SDI traces.
Because CallManager is at the heart of a CIPT network, CCM traces are usually the
first place to look when troubleshooting most problems. You can analyze problems
related to device registration, call flow, digit analysis, and related devices such as IP
phones, gateways, gatekeepers, and more. By the end of this section, you should be
able to follow some basic call flows in the CCM trace. Future chapters continue to
show CCM trace examples as you learn how to troubleshoot more problems. Later in
this chapter you also learn about the Q.931 Translator, which is useful for quickly
troubleshooting a variety of gateway problems. It is not a substitute for learning how
to read the CCM trace, but it helps you quickly examine a trace in a graphical format
51. without having to wade through irrelevant debugs. See the later "Q.931 Translator
and Enhanced Q.931 Translator" section for more information.
Setting the Appropriate Trace Level and Flags
CallManager allows you to select from a variety of different options that adjust which
events are logged to the CCM trace files. If you know exactly what you are looking
for, you can configure CallManager to log only specific events in the CCM trace file. If
you configure the trace to collect too much information, the trace becomes more
difficult to analyze. However, if you do not configure the trace to collect enough
information, you might miss the problem you are trying to find. When you are
beginning to learn how to read CCM trace files, it is best to enable more debugs than
less. As you learn which trace settings are required for specific problems, you can
enable just the settings you need.
Unfortunately you can never predict what problems will come up, so if you do not
have a high level of tracing enabled, you may have to wait for a problem to happen a
second time after enabling the appropriate trace settings before you can
troubleshoot. For this reason, it is usually best to leave a majority of the trace flags
enabled during normal operating con-ditions so you have trace data available if a
problem occurs.
You configure a CCM trace in Cisco CallManager Serviceability (Trace >
Configuration). Figure 3-1 shows the top half of the Trace Configuration page, and
this section discusses the relevant fields and settings on that page.
Figure 3-1. Trace Configuration (Part 1) in CallManager
Serviceability
52. First thing to note is the Trace On checkbox. This must be selected for any of the
trace settings to be available.
The Apply to All Nodes checkbox allows you to apply the specified trace settings to
all CallManager servers in the cluster. This is useful when you are troubleshooting a
problem that is occurring on more than one CallManager server. You generally want
to keep the same level of tracing enabled on all the servers in the cluster unless you
are absolutely certain the problem is isolated to a single server in the cluster.
Because of the distributed nature of CallManager, you may think a process only
involves a single server when in reality part of the processing for a particular call is
occuring on another server in the cluster.
The Trace Filter Settings area allows you to specify the exact parameters of your
trace. First, you set the level of tracing you want to perform in the Debug Trace
Level field. CallManager Serviceability provides six different levels, but for nearly
every kind of problem that you'll want traces for, the recommended levels are either
Detailed or Arbitrary:
53. • Detailed— Provides detailed debug information and highly repetitive
messages that are primarily used for debugging, including KeepAlives and
responses. For CallManager releases 3.1 and earlier, be cautious about using
this level during normal production hours on a heavily loaded system. It can
cause performance degradation on CallManager. In release 3.2 and later,
CallManager uses asynchronous tracing to reduce the impact that trace file
generation has on call processing.
• Arbitrary— Provides low-level debug traces. This level is best suited for
debugging difficult problems. This level includes nearly everything that is
included in Detailed with the exception of KeepAlives. If you are not
troubleshooting problems related to missed KeepAlives, this level is good for
day-to-day troubleshooting.
Other trace levels are provided, but generally, they don't offer as much information
as the Detailed and Arbitrary levels. The other levels are
• Error— Provides traces generated in abnormal conditions, such as coding
errors or other errors that normally should not occur.
• Special— Provides traces for all informational, non-repetitive messages such
as process startup messages, registration messages, and so on. All system
and device initialization traces are at this level.
• State Transition— Provides traces for call processing events or normal
events traced for the subsystem (signaling layers).
• Significant— Provides traces for media layer events.
Second, make sure the Enable CallManager Trace Fields checkbox is selected,
which gives you the opportunity to select which specific traces you want to run and
to choose your traces. Table 3-1 describes the trace fields to choose from. Most are
reasonably self-explanatory. For example, if you're having problems with an H.323
device, you would enable the H245 Message Trace and Enable H225 &
Gatekeeper Trace options. Likewise, for music on hold (MOH) issues, the Enable
Music on Hold option would display trace relating to all MOH activity.
Table 3-1. Cisco CallManager Trace Fields
Field Name Description
Enable H245
Message Trace
Debugs H.245 signaling for H.323 calls, including the media
processing messages.
Enable DT-
24+/DE-30+ Trace
Activates the logging of events related to the legacy gateways,
Cisco Digital Access DT-24+/DE-30+.
Enable PRI Trace Activates a trace of Primary Rate Interface (PRI) devices.
Enable ISDN
Translation Trace
Activates a Layer 3 trace of Q.931 (ISDN messages).
Enable H225 &
Gatekeeper Trace
Activates a trace showing H.225 signaling messaging for H.323
calls.
Enable
Miscellaneous
Trace
Activates a trace of miscellaneous devices.
Enable Conference
Bridge Trace
Activates a trace of the conference bridges. Use this level to
trace conference bridge statuses such as
54. Table 3-1. Cisco CallManager Trace Fields
Field Name Description
• Registered with CallManager
• Unregistered with CallManager
• Resource allocation processed successfully
• Resource allocation failed
Enable Music on
Hold Trace
Activates a trace of MOH devices. Use this level to trace MOH
device statuses such as
• Registered with CallManager
• Unregistered with CallManager
• Resource allocation processed successfully
• Resource allocation failed
Enable CM Real-
Time Information
Server Trace
Activates CallManager real-time information traces used by the
real-time information server.
Enable CDR Trace Enables tracing of call detail record (CDR) processing. However,
this trace flag does not provide much information about CDRs
because CDR processing is mostly handled by the Database
Layer Monitor and CDR Insert services discussed in Chapter 17,
"SQL Database Replication."
Enable Analog
Trunk Trace
Activates a trace of all MGCP-based devices using an analog
interface.
Enable All Phone
Device Trace
Activates a trace of phone devices, including Cisco IP
SoftPhones, and shows events such as on-hook, off-hook, key
presses, and so on.
Enable MTP Trace Activates a trace of media termination point devices and
transcoders. Use this level to trace MTP device statuses such as
• Registered with CallManager
• Unregistered with CallManager
• Resource allocation processed successfully
• Resource allocation failed
Enable All Gateway
Trace
Activates a trace of all analog and digital gateways.
Enable Forward
and Miscellaneous
Trace
Activates a trace of call forwarding and all subsystems not
covered by another checkbox.
Enable MGCP Trace Activates a trace showing media gateway control protocol
(MGCP) messages for MGCP-based devices.
Enable Media Activates a trace for media resource manager (MRM) activities.
56. only sixpence and Converse not a penny to bless himself with, so
they were compelled to forego this pledge of friendship and part
with thirsty lips. Going on to Roxbury, Church luckily found an old
neighbor of his, who generously lent him money enough to get
home with. He tells the anecdote in order to show to what straits the
parsimony of the Massachusetts rulers had reduced him, their great
captain, to whom the colony owed so much.
The Red Lion, in North Street, was one of the oldest public houses,
if not the oldest, to be opened at the North End of the town. It
stood close to the waterside, the adjoining wharf and the lane
running down to it both belonging to the house and both taking its
name. The old Red Lion Lane is now Richmond Street, and the wharf
has been filled up, so making identification of the old sites difficult,
to say the least. Nicholas Upshall, the stout-hearted Quaker, kept the
Red Lion as early as 1654. At his death the land on which tavern and
brewhouse stood went to his children. When the persecution of his
sect began in earnest, Upshall was thrown into Boston jail, for his
outspoken condemnation of the authorities and their rigorous
proceedings toward this people. He was first doomed to perpetual
imprisonment. A long and grievous confinement at last broke
Upshall’s health, if it did not, ultimately, prove the cause of his
death.
The Ship Tavern stood at the head of Clark’s Wharf, or on the
southwest corner of North and Clark streets, according to present
boundaries. It was an ancient brick building, dating as far back as
1650 at least. John Vyal kept it in 1663. When Clark’s Wharf was
built it was the principal one of the town. Large ships came directly
up to it, so making the tavern a most convenient resort for masters
of vessels or their passengers, and associating it with the locality
itself. King Charles’s commissioners lodged at Vyal’s house, when
they undertook the task of bringing down the pride of the rulers of
the colony a peg. One of them, Sir Robert Carr, pummeled a
constable who attempted to arrest him in this house. He afterward
refused to obey a summons to answer for the assault before the
57. magistrates, loftily alleging His Majesty’s commission as superior to
any local mandate whatever. He thus retaliated Governor Leverett’s
affront to the commissioners in keeping his hat on his head when
their authority to act was being read to the council. But Leverett was
a man who had served under Cromwell, and had no love for the
cavaliers or they for him. The commissioners sounded trumpets and
made proclamations; but the colony kept on the even tenor of its
way, in defiance of the royal mandate, equally regardless of the
storm gathering about it, as of the magnitude of the conflict in which
it was about to plunge, all unarmed and unprepared.
58. III.
IN REVOLUTIONARY TIMES.
uch thoroughfares as King Street, just before the
Revolution, were filled with horsemen, donkeys, oxen, and
long-tailed trucks, with a sprinkling of one-horse chaises
and coaches of the kind seen in Hogarth’s realistic pictures of
London life. To these should be added the chimney-sweeps, wood-
sawyers, market-women, soldiers, and sailors, who are now quite as
much out of date as the vehicles themselves are. There being no
sidewalks, the narrow footway was protected, here and there,
sometimes by posts, sometimes by an old cannon set upright at the
corners, so that the traveller dismounted from his horse or alighted
from coach or chaise at the very threshold.
Next in the order of antiquity, as well as fame, to the taverns already
named, comes the Bunch of Grapes in King, now State Street. The
plain three-story stone building situated at the upper corner of Kilby
Street stands where the once celebrated tavern did. Three gilded
clusters of grapes dangled temptingly over the door before the eye
of the passer-by. Apart from its palate-tickling suggestions, a
pleasant aroma of antiquity surrounds this symbol, so dear to all
devotees of Bacchus from immemorial time. In Measure for Measure
the clown says, “’Twas in the Bunch of Grapes, where indeed you
have a delight to sit, have you not?” And Froth answers, “I have so,
because it is an open room and good for winter.”
59. THE BUNCH OF GRAPES
This house goes back to the year 1712, when Francis Holmes kept it,
and perhaps further still, though we do not meet with it under this
title before Holmes’s time. From that time, until after the Revolution,
it appears to have always been open as a public inn, and, as such, is
feelingly referred to by one old traveller as the best punch-house to
be found in all Boston.
When the line came to be drawn between conditional loyalty, and
loyalty at any rate, the Bunch of Grapes became the resort of the
High Whigs, who made it a sort of political headquarters, in which
patriotism only passed current, and it was known as the Whig
tavern. With military occupation and bayonet rule, still further
intensifying public feeling, the line between Whig and Tory houses
was drawn at the threshold. It was then kept by Marston. Cold
welcome awaited the appearance of scarlet regimentals or a Tory
phiz there; so gentlemen of that side of politics also formed cliques
of their own at other houses, in which the talk and the toasts were
more to their liking, and where they could abuse the Yankee rebels
over their port to their heart’s content.
60. But, apart from political considerations, one or two incidents have
given the Bunch of Grapes a kind of pre-eminence over all its
contemporaries, and, therefore, ought not to be passed over when
the house is mentioned.
On Monday, July 30, 1733, the first grand lodge of Masons in
America was organized here by Henry Price, a Boston tailor, who had
received authority from Lord Montague, Grand Master of England,
for the purpose.
Again, upon the evacuation of Boston by the royal troops, this house
became the centre for popular demonstrations. First, His Excellency,
General Washington, was handsomely entertained there. Some
months later, after hearing the Declaration read from the balcony of
the Town-house, the populace, having thus made their appeal to the
King of kings, proceeded to pull down from the public buildings the
royal arms which had distinguished them, and, gathering them in a
heap in front of the tavern, made a bonfire of them, little imagining,
we think, that the time would ever come when the act would be
looked upon as vandalism on their part.
General Stark’s timely victory at Bennington was celebrated with all
the more heartiness of enthusiasm in Boston because the people
had been quaking with fear ever since the fall of Ticonderoga sent
dismay throughout New England. The affair is accurately described
in the following letter, written by a prominent actor, and going to
show how such things were done in the times that not only tried
men’s souls, but would seem also to have put their stomachs to a
pretty severe test. The writer says:—
“In consequence of this news we kept it up in high taste. At
sundown about one hundred of the first gentlemen of the town, with
all the strangers then in Boston, met at the Bunch of Grapes, where
good liquors and a side-table were provided. In the street were two
brass field-pieces with a detachment of Colonel Craft’s regiment. In
the balcony of the Town-house all the fifes and drums of my
regiment were stationed. The ball opened with a discharge of
61. thirteen cannon, and at every toast given three rounds were fired
and a flight of rockets sent up. About nine o’clock two barrels of
grog were brought out into the street for the people that had
collected there. It was all conducted with the greatest propriety, and
by ten o’clock every man was at his home.”
Shortly after this General Stark himself arrived in town and was right
royally entertained here, at that time presenting the trophies now
adorning the Senate Chamber. On his return from France in 1780
Lafayette was also received at this house with all the honors, on
account of having brought the news that France had at last cast her
puissant sword into the trembling balance of our Revolutionary
contest.
But the important event with which the Bunch of Grapes is
associated is, not the reception of a long line of illustrious guests,
but the organization, by a number of continental officers, of the Ohio
Company, under which the settlement of that great State began in
earnest, at Marietta. The leading spirit in this first concerted
movement of New England toward the Great West was General
Rufus Putnam, a cousin of the more distinguished officer of
Revolutionary fame.
Taking this house as a sample of the best that the town could afford
at the beginning of the century, we should probably find a company
of about twenty persons assembled at dinner, who were privileged to
indulge in as much familiar chat as they liked. No other formalities
were observed than such as good breeding required. Two o’clock
was the hour at which all the town dined. The guests were called
together by the ringing of a bell in the street. They were served with
salmon in season, veal, beef, mutton, fowl, ham, vegetables, and
pudding, and each one had his pint of Madeira set before him. The
carving was done at the table in the good old English way, each
guest helping himself to what he liked best. Five shillings per day
was the usual charge, which was certainly not an exorbitant one. In
half an hour after the cloth was removed the table was usually
deserted.
62. The British Coffee-House was one of the first inns to take to itself
the newly imported title. It stood on the site of the granite building
numbered 66 State Street, and was, as its name implies, as
emphatically the headquarters of the out-and-out loyalists as the
Bunch of Grapes, over the way, was of the unconditional Whigs. A
notable thing about it was the performance there in 1750, probably
by amateurs, of Otway’s “Orphan,” an event which so outraged
public sentiment as to cause the enactment of a law prohibiting the
performance of stage plays under severe penalties.
Perhaps an even more notable occurrence was the formation in this
house of the first association in Boston taking to itself the distinctive
name of a Club. The Merchants’ Club, as it was called, met here
as early as 1751. Its membership was not restricted to merchants,
as might be inferred from its title, though they were possibly in a
majority, but included crown officers, members of the bar, military
and naval officers serving on the station, and gentlemen of high
social rank of every shade of opinion. No others were eligible to
membership.
Up to a certain time this club, undoubtedly, represented the best
culture, the most brilliant wit, and most delightful companionship
that could be brought together in all the colonies; but when the
political sky grew dark the old harmony was at an end, and a
division became inevitable, the Whigs going over to the Bunch of
Grapes, and thereafter taking to themselves the name of the Whig
Club.[1]
Under date of 1771, John Adams notes down in his Diary this item:
“Spent the evening at Cordis’s, in the front room towards the Long
Wharf, where the Merchants’ Club has met these twenty years. It
seems there is a schism in that church, a rent in that garment.”
Cordis was then the landlord.[2]
Social and business meetings of the bar were also held at the
Coffee-House, at one of which Josiah Quincy, Jr. was admitted. By
and by the word “American” was substituted for “British” on the
63. Coffee-House sign, and for some time it flourished under its new title
of the American Coffee-House.
But before the clash of opinions had brought about the secession
just mentioned, the best room in this house held almost nightly
assemblages of a group of patriotic men, who were actively
consolidating all the elements of opposition into a single force. Not
inaptly they might be called the Old Guard of the Revolution. The
principals were Otis, Cushing, John Adams, Pitts, Dr. Warren, and
Molyneux. Probably no minutes of their proceedings were kept, for
the excellent reason that they verged upon, if they did not overstep,
the treasonable.
His talents, position at the bar, no less than intimate knowledge of
the questions which were then so profoundly agitating the public
mind, naturally made Otis the leader in these conferences, in which
the means for counteracting the aggressive measures then being put
in force by the ministry formed the leading topic of discussion. His
acute and logical mind, mastery of public law, intensity of purpose,
together with the keen and biting satire which he knew so well how
to call to his aid, procured for Otis the distinction of being the best-
hated man on the Whig side of politics, because he was the one
most feared. Whether in the House, the court-room, the taverns, or
elsewhere, Otis led the van of resistance. In military phrase, his
policy was the offensive-defensive. He was no respecter of ignorance
in high places. Once when Governor Bernard sneeringly interrupted
Otis to ask him who the authority was whom he was citing, the
patriot coldly replied, “He is a very eminent jurist, and none the less
so for being unknown to your Excellency.”
It was in the Coffee-House that Otis, in attempting to pull a Tory
nose, was set upon and so brutally beaten by a place-man named
Robinson, and his friends, as to ultimately cause the loss of his
reason and final withdrawal from public life. John Adams says he
was “basely assaulted by a well-dressed banditti, with a
commissioner of customs at their head.” What they had never been
able to compass by fair argument, the Tories now succeeded in
64. accomplishing by brute force, since Otis was forever disqualified
from taking part in the struggle which he had all along foreseen was
coming,—and which, indeed, he had done more to bring about than
any single man in the colonies.
Connected with this affair is an anecdote which we think merits a
place along with it. It is related by John Adams, who was an
interested listener. William Molyneux had a petition before the
legislature which did not succeed to his wishes, and for several
evenings he had wearied the company with his complaints of
services, losses, sacrifices, etc., always winding up with saying,
“That a man who has behaved as I have should be treated as I am
is intolerable,” with much more to the same effect. Otis had said
nothing, but the whole club were disgusted and out of patience,
when he rose from his seat with the remark, “Come, come, Will, quit
this subject, and let us enjoy ourselves. I also have a list of
grievances; will you hear it?” The club expected some fun, so all
cried out, “Ay! ay! let us hear your list.”
“Well, then, in the first place, I resigned the office of advocate-
general, which I held from the crown, which produced me—how
much do you think?”
“A great deal, no doubt,” said Molyneux.
“Shall we say two hundred sterling a year?”
“Ay, more, I believe,” said Molyneux.
“Well, let it be two hundred. That, for ten years, is two thousand. In
the next place, I have been obliged to relinquish the greater part of
my business at the bar. Will you set that at two hundred pounds
more?”
“Oh, I believe it much more than that!” was the answer.
“Well, let it be two hundred. This, for ten years, makes two
thousand. You allow, then, I have lost four thousand pounds
sterling?”
65. “Ay, and more too,” said Molyneux. Otis went on: “In the next place,
I have lost a hundred friends, among whom were men of the first
rank, fortune, and power in the province. At what price will you
estimate them?”
“D—n them!” said Molyneux, “at nothing. You are better off without
them than with them.”
A loud laugh from the company greeted this sally.
“Be it so,” said Otis. “In the next place, I have made a thousand
enemies, among whom are the government of the province and the
nation. What do you think of this item?”
“That is as it may happen,” said Molyneux, reflectively.
“In the next place, you know I love pleasure, but I have renounced
pleasure for ten years. What is that worth?”
“No great matter: you have made politics your amusement.”
A hearty laugh.
“In the next place, I have ruined as fine health as nature ever gave
to man.”
“That is melancholy indeed; there is nothing to be said on that
point,” Molyneux replied.
“Once more,” continued Otis, holding down his head before
Molyneux, “look upon this head!” (there was a deep, half-closed scar,
in which a man might lay his finger)—“and, what is worse my friends
think I have a monstrous crack in my skull.”
This made all the company look grave, and had the desired effect of
making Molyneux who was really a good companion, heartily
ashamed of his childish complaints.
66. Larger Image
Another old inn of assured celebrity was the Cromwell’s Head, in
School Street. This was a two-story wooden building of venerable
appearance, conspicuously displaying over the footway a grim
likeness of the Lord Protector, it is said much to the disgust of the
ultra royalists, who, rather than pass underneath it, habitually took
the other side of the way. Indeed, some of the hot-headed Tories
were for serving Cromwell’s Head as that man of might had served
their martyr king’s. So, when the town came under martial law, mine
host Brackett, whose family kept the house for half a century or
more, had to take down his sign, and conceal it until such time as
67. the “British hirelings” should have made their inglorious exit from the
town.
After Braddock’s crushing defeat in the West, a young Virginian
colonel, named George Washington, was sent by Governor Dinwiddie
to confer with Governor Shirley, who was the great war governor of
his day, as Andrew was of our own, with the difference that Shirley
then had the general direction of military affairs, from the Ohio to
the St. Lawrence, pretty much in his own hands. Colonel Washington
took up his quarters at Brackett’s, little imagining, perhaps, that
twenty years later he would enter Boston at the head of a victorious
republican army, after having quartered his troops in Governor
Shirley’s splendid mansion.
Major-General the Marquis Chastellux, of Rochambeau’s auxiliary
army, also lodged at the Cromwell’s Head when he was in Boston in
1782. He met there the renowned Paul Jones, whose excessive
vanity led him to read to the company in the coffee-room some
verses composed in his own honor, it is said, by Lady Craven.
68. From the tavern of the gentry we pass on to the tavern of the
mechanics, and of the class which Abraham Lincoln has forever
distinguished by the title of the common people.
Among such houses the Salutation, which stood at the junction of
Salutation with North Street, is deserving of a conspicuous place. Its
vicinity to the shipyards secured for it the custom of the sturdy North
End shipwrights, caulkers, gravers, sparmakers, and the like,—a
numerous body, who, while patriots to the backbone, were also quite
clannish and independent in their feelings and views, and
consequently had to be managed with due regard to their class
prejudices, as in politics they always went in a body. Shrewd
politicians, like Samuel Adams, understood this. Governor Phips
owed his elevation to it. As a body, therefore, these mechanics were
extremely formidable, whether at the polls or in carrying out the
plans of their leaders. To their meetings the origin of the word
caucus is usually referred, the word itself undoubtedly having come
into familiar use as a short way of saying caulkers’ meetings.
The Salutation became the point of fusion between leading Whig
politicians and the shipwrights. More than sixty influential mechanics
attended the first meeting, called in 1772, at which Dr. Warren drew
up a code of by-laws. Some leading mechanic, however, was always
chosen to be the moderator. The “caucus,” as it began to be called,
continued to meet in this place until after the destruction of the tea,
when, for greater secrecy, it became advisable to transfer the
sittings to another place, and then the Green Dragon, in Union
Street, was selected.
The Salutation had a sign of the sort that is said to tickle the popular
fancy for what is quaint or humorous. It represented two citizens,
with hands extended, bowing and scraping to each other in the most
approved fashion. So the North-Enders nicknamed it “The Two
Palaverers,” by which name it was most commonly known. This
house, also, was a reminiscence of the Salutation in Newgate Street,
London, which was the favorite haunt of Lamb and Coleridge.
69. The Green Dragon will probably outlive all its contemporaries in
the popular estimation. In the first place a mural tablet, with a
dragon sculptured in relief, has been set in the wall of the building
that now stands upon some part of the old tavern site. It is the only
one of the old inns to be so distinguished. Its sign was the fabled
dragon, in hammered metal, projecting out above the door, and was
probably the counterpart of the Green Dragon in Bishopsgate Street,
London.
THE GREEN DRAGON TAVERN
As a public house this one goes back to 1712, when Richard Pullen
kept it; and we also find it noticed, in 1715, as a place for entering
horses to be run for a piece of plate of the value of twenty-five
pounds. In passing, we may as well mention the fact that Revere
Beach was the favorite race-ground of that day. The house was well
situated for intercepting travel to and from the northern counties.
70. THE GREEN DRAGON.
To resume the historical connection between the Salutation and
Green Dragon, its worthy successor, it appears that Dr. Warren
continued to be the commanding figure after the change of location;
and, if he was not already the popular idol, he certainly came little
short of it, for everything pointed to him as the coming leader whom
the exigency should raise up. Samuel Adams was popular in a
different way. He was cool, far-sighted, and persistent, but he
certainly lacked the magnetic quality. Warren was much younger, far
more impetuous and aggressive,—in short, he possessed all the
more brilliant qualities for leadership which Adams lacked. Moreover,
he was a fluent and effective speaker, of graceful person, handsome,
affable, with frank and winning manners, all of which added no little
to his popularity. Adams inspired respect, Warren confidence. As
Adams himself said, he belonged to the “cabinet,” while Warren’s
whole make-up as clearly marked him for the field.
In all the local events preliminary to our revolutionary struggle, this
Green Dragon section or junto constituted an active and positive
force. It represented the muscle of the Revolution. Every member
was sworn to secrecy, and of them all one only proved recreant to
his oath.
71. These were the men who gave the alarm on the eve of the battle of
Lexington, who spirited away cannon under General Gage’s nose,
and who in so many instances gallantly fought in the ranks of the
republican army. Wanting a man whom he could fully trust, Warren
early singled out Paul Revere for the most important services. He
found him as true as steel. A peculiar kind of friendship seems to
have sprung up between the two, owing, perhaps, to the same
daring spirit common to both. So when Warren sent word to Revere
that he must instantly ride to Lexington or all would be lost, he knew
that, if it lay in the power of man to do it, the thing would be done.
Besides the more noted of the tavern clubs there were numerous
private coteries, some exclusively composed of politicians, others
more resembling our modern debating societies than anything else.
These clubs usually met at the houses of the members themselves,
so exerting a silent influence on the body politic. The non-
importation agreement originated at a private club in 1773. But all
were not on the patriot side. The crown had equally zealous
supporters, who met and talked the situation over without any of the
secrecy which prudence counselled the other side to use in regard to
their proceedings. Some associations endeavored to hold the
balance between the factions by standing neutral. They deprecated
the encroachments of the mother-country, but favored passive
obedience. Dryden has described them:
“Not Whigs nor Tories they, nor this nor that,
Nor birds nor beasts, but just a kind of bat,—
A twilight animal, true to neither cause,
With Tory wings but Whiggish teeth and claws.”
It should be mentioned that Gridley, the father of the Boston Bar,
undertook, in 1765, to organize a law club, with the purpose of
making head against Otis, Thatcher, and Auchmuty. John Adams and
Fitch were Gridley’s best men. They met first at Ballard’s, and
subsequently at each other’s chambers; their “sodality,” as they
called it, being for professional study and advancement. Gridley, it
appears, was a little jealous of his old pupil, Otis, who had beaten
72. him in the famous argument on the Writs of Assistance. Mention is
also made of a club of which Daniel Leonard (Massachusettensis),
John Lowell, Elisha Hutchinson, Frank Dana, and Josiah Quincy were
members. Similar clubs also existed in most of the principal towns in
New England.
The Sons of Liberty adopted the name given by Colonel Barré to
the enemies of passive obedience in America. They met in the
counting-room of Chase and Speakman’s distillery, near Liberty Tree.
[3] Mackintosh, the man who led the mob in the Stamp Act riots, is
doubtless the same person who assisted in throwing the tea
overboard. We hear no more of him after this. The “Sons” were an
eminently democratic organization, as few except mechanics were
members. Among them were men like Avery, Crafts, and Edes the
printer. All attained more or less prominence. Edes continued to print
the Boston Gazette long after the Revolution. During Bernard’s
administration he was offered the whole of the government printing,
if he would stop his opposition to the measures of the crown. He
refused the bribe, and his paper was the only one printed in America
without a stamp, in direct violation of an Act of Parliament. The
“Sons” pursued their measures with such vigor as to create much
alarm among the loyalists, on whom the Stamp Act riots had made a
lasting impression. Samuel Adams is thought to have influenced their
proceedings more than any other of the leaders. It was by no means
a league of ascetics, who had resolved to mortify the flesh, as punch
and tobacco were liberally used to stimulate the deliberations.
73. THE LIBERTY TREE
No important political association outlived the beginning of
hostilities. All the leaders were engaged in the military or civil service
on one or the other side. Of the circle that met at the Merchants’
three were members of the Philadelphia Congress of 1774, one was
president of the Provincial Congress of Massachusetts, the career of
two was closed by death, and that of Otis by insanity.
75. IV.
SIGNBOARD HUMOR.
nother tavern sign, though of later date, was that of the
Good Woman, at the North End. This Good Woman was
painted without a head.
Still another board had painted on it a bird, a tree, a ship, and a
foaming can, with the legend,—
“This is the bird that never flew,
This is the tree which never grew,
This is the ship which never sails,
This is the can which never fails.”
76. The Dog and Pot, Turk’s Head, Tun and Bacchus, were also old
and favorite emblems. Some of the houses which swung these signs
were very quaint specimens of our early architecture. So, also, the
signs themselves were not unfrequently the work of good artists.
Smibert or Copley may have painted some of them. West once
offered five hundred dollars for a red lion he had painted for a
tavern sign.
DOG AND POT.
Not a few boards displayed a good deal of ingenuity and mother-wit,
which was not without its effect, especially upon thirsty Jack, who
could hardly be expected to resist such an appeal as this one of the
Ship in Distress:
“With sorrows I am compass’d round;
Pray lend a hand, my ship’s aground.”
We hear of another signboard hanging out at the extreme South End
of the town, on which was depicted a globe with a man breaking
through the crust, like a chicken from its shell. The man’s nakedness
was supposed to betoken extreme poverty.
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