dissertation

TRAFFIC ENGINEERING WITH
MULTI PROTOCOL LABEL
SWITCHING
(CORE NETWORKS)
Sumit Lakhanpal
BIRMINGHAM CITY UNIVERSITY
MSc
January 2010

TRAFFIC ENGINEERING WITH MULTI
PROTOCOL LABEL SWITCHING
(CORE NETWORKS)
Sumit Lakhanpal
A dissertation submitted in partial fulfilment of the requirements of
the
Birmingham City University for the degree of
Master of Science
January 2010
Technology Innovation and Development
in collaboration with
Birmingham City University.

ACKNOWLEDGEMENTS
First and foremost I would like to thank Almighty God for giving endurance
and knowledge needed to complete the project.
Words elude in expressing my profound gratitude to our project co-ordinator
Mr. Michael Clarke for his guidance and suggestions. Also his patient and
understanding attitude, which made him very easy to talk, liaise with.
I am grateful to Mr Ron Austin for his constructive encouragement and
thought provoking discussions which helped us while our project was
underway.
I also take privilege to record my deepest appreciation and heartiest thanks to
Mr. Richard, without whose benign cooperation; we would not have completed
our project successfully. We would also like to thank other staff members of
Communication and Networks Centre for lending a helping hand wherever
needed.
I would like to thank my family, colleagues and friends for all their motivation
and support.

ABSTRACT
Traffic Engineering (TE) is a specific branch of computer science which deals
with designing, planning and organising data traffic across networks. TE aims
at issues related to performance optimisation on active networks. TE primarily
deals with network capacity management, network reliability, effective data
communication and efficient use of network resources. IP is the most common
and widely used platform across networks. However IP networks are less
secure and do not guarantee Quality of Service. This research work explains
the performance issues in traffic engineering and recommends a solution of
Multi-Protocol Label Switching (MPLS). MPLS is an advanced technique of
forwarding data across networks. MPLS provides the traffic engineering
capabilities to the IP networks. In the past few years MPLS Traffic
Engineering is the most common and widely used mechanism to transport
critical data over multi-service networks. Due to the insufficient resources
required for the project, GNS (virtual network platform) has been used to
analyse MPLS in a simulated environment. This report explains why and how
MPLS is more efficient and effective than the previous techniques. It also
shows performance comparison of various technologies like Cell Switching
Router (CSR), Tag Switching, IP Switching and Aggregate Route IP Switching
(ARIS).This report shows the performance analysis of MPLS TE technology
as compared to the traditional IP networks in terms of QoS, average
throughput, congestion control and bandwidth optimization. This report
concludes that MPLS proves out to be a better technology as compared to the
traditional IP with respect to the above mentioned features because of its
traffic engineering (TE) capability in IP network.
Keywords:

Multi-Protocol Label Switching (MPLS), Internet Protocol (IP), Congestion
Control, Quality of Service (QoS), Traffic Engineering (TE)
1 INTRODUCTION
People across the globe communicate through internet. Internet has become
the necessity of today’s life. With the expansion of internet, the requirements
of the several users is becoming relatively high, especially the real time
applications like voice and video are highly critical and time sensitive. These
users require guaranteed network resources and quality of service (QOS).
Therefore it is very important for the service providers to provide excellent
network services and to make sure that they are running effectively there
after, meeting the quality standards at no extra costs. So in order to survive in
the competition service providers have to provide cheap and effective
solutions with the help of different technologies and MPLS is one of the most
common and widely used mechanisms in the industry.
In traditional IP based networks, routing decision is based on the information
contained in the network layer header. Each router has to look up its routing
table before been able to send the packet in the right direction. This method of
route determination consumes a lot of CPU time which results in increased
network traffic and even data loss in some cases. Thus there is a need of a
scalable and effective method of routing data packets. Therefore IETF
(Internet Engineering Task Force) proposed MPLS (Multi Protocol Label
Switching) which included traffic engineering capabilities on IP networks. The
goal of MPLS is to provide greater switching power based on the information
of the label attached to the packet. Routers then don’t have to look in to their
routing tables or in to the content of the packets to make routing decisions,
which in turn saves a lot of time and CPU wastage. MPLS provisions IP
routing over ATM (asynchronous transfer mode) networks and therefore it has
the speed, capacity and multi service capability of ATM networks along with

the simplicity, scalability and robustness of IP networks. MPLS-TE combines
the best of traffic engineering methods with IP based routing.
For the core network, network engineers use MPLS VPN for enhanced
security and reliability. However, on a shared network sometimes they
become very complex which leads to network congestion. MPLS is very
effective and efficient technology but still does not offer support for the Next
Generation Networks. Most of the people use MPLS technology over ATM
and Frame Relay core networks which are considered expensive and difficult
to troubleshoot.
1.1 DEFINITION OF PROBLEM
In the beginning internet was discovered for US military’s private use but with
the passage of time, internet has reached millions of users. Internet of today
connects businesses, people, cultures, nations and organisations. Internet is
growing exponentially and so is the demand of the users. With an
unpredictable increase in the use of internet application for various uses,
internet lines are becoming highly congested. And to match this growing
demand Internet Service Providers (ISP) are continuously developing several
applications, algorithms and technologies.
The most congested parts of the internet are the backbone networks or the
networks connected to ISP. A backbone network is a base network to which
different components of a network are connected so that they can share
information with each other. And because every user request while trying to
access a network resource has to go through the backbone network which
makes it highly congested. The utilisation rate of a backbone network when
measured is always steady which proves that these networks are consistently
under high pressure.

MPLS VPN also known as the new edge overlay models are commonly used
in the core on a shared network. On the shared network different users are
trying to access the same set of resource at the same time which leads to
congestion in the core networks. Paths with maximum traffic are the links from
IP Networks to the backbone networks. IP networks provide less QOS, some
delays and data losses. In IP networks data is routed on the basis of SPF
(Shortest Path First) algorithm and the shortest path gets congested because
other sites are trying to connect to the same server. Thus the shortest path no
longer remains the fastest path. Now when the path gets congested, in order
to reroute the traffic from another path the whole metric has to be changed.
For an example any popular website will have lots of users, service provider in
such a case cannot predict the growth of demand and the link gets congested
in a very short time which leads to link going down. So SP have to find an
easily manageable solution to reduce complexity and increase availability to
attract the new clients. At the same time the solution should be cost effective
to implement and should generate more revenue for service providers
Traffic Engineering with MPLS is used to fix these issues, however TE also
has some problems. Firstly many networks of different size, speed and type
are emerging day by day. They join themselves with the older networks, which
leads to a complex situation. Secondly expectation of millions of users is
increasing as every user needs better performance, high availability and high
security. Also ISPs do not have any low level controls over data scheduling,
path selection and buffer management.
Traffic Engineering routing protocol CSPF, constraint based routing provides
guaranteed resources and protection against virtual lease line failures with the
help of RSVP (Resource reservation protocol). Thus MPLS helps control
network traffic with the help of TE. This thesis addresses to the real time
problems faced by the operational networks and suggests MPLS TE as a
solution. This report also explores the different methods of implementing
MPLS TE, their advantages and their limitations.

Problem of Network Congestion and IP address Shortage
The current operational networks consistently strive to achieve a solution to
the numerous problems.
Availability
For the optimum performance of the networks there has to be enough
resources available at all times. Network of today are over utilising the
resources. Higher end network applications like voice and video data, online
multimedia services consume a lot of network resources. Thus there is a
continuous process of developing new ideas to provide guaranteed resources.
Scalability
As discussed earlier there is big problem in front of Service Providers and
Network Engineers to save IP addresses. With the passage of time various
technologies like VLSM (Variable Length Subnet Mask) and CIDR (Classless
Inter Domain Routing) evolved to solve this problem. But since the networks
are growing at an enormous scale and Internet Assigned Numbers Authority
(IANA) has a limited set of IP, there is a need of an effective method which
can scale very well. Also should be taken in to account the factors affecting
the scalability and the limits in which it can scale.
Reliability and Security
Reliability is what a network stands on. Current networks face a lot of
problems like link failures, hardware device faults, router firmware issues etc.
Once the network is operational the security and reliability of the network
becomes very important because of the critical information it carries. A
solution therefore should be designed which is secure and can carry data
effectively and efficiently. Figure 18 shows the problem faced due to hardware

failure. Mentioned below are some real time scenarios of traffic congestion
which had adverse effects.
UUNet /Worldcom backbone difficulties
Dateline: 10/3/2002
For several hours UUNet/ Worldcom suffered severe routing issues, which
impacted most of their network. The failure caused losses of routes, BGP
failures, routing loops, and over-utilization on some circuits during this time.
UUNet/World com reconverged their router tables, but still experienced
increased latency of several hours thereafter.
http://www.internettrafficreport.com/event.htm
Backbone DDoS
Dateline: 10/22/2002
At 1:45pm for about one hour an extremely large distributed denial-of-server
(DDoS) attack took place. The target of the attack were the 13 DNS root
servers, which are responsible forhelping to resolving domain names to their
respective IP's. Even though 9 of the 13 servers were disabled in the attack,
the remaining were able to support the additional load without any widespead
problems. Prior to this attack, the largest outage for the root registry was 7
machines in July of 1997, due to a technical problem.
SQL Slammer worm
Dateline: 1/24/2003

A worm designed to take advantage of a vulnerability in Microsoft SQL to gain
control of the server affected a large percentage of the Internet. Once the
worm had infected a server it began scanning the network for more vulnerable
systems, causing packet loss or completely saturating circuits in some
instances. Several large Internet transit providers and end-user ISP's were
completely shut down as a result, with affects varying from slow browsing to
disabling ATM machines.
Major power failure on east coast
Dateline: 8/14/2003
A major power outage that occurred at approx 2pm MST (4pm EDT) effected
most of the north-eastern coast of the United States including major cities
such as New York, Detroit, and parts of Canada. The impact on the Internet
(in regards to server availability) was not nearly as dramatic as the
UUNet/Worldcom backbone problem, due to almost all data centers having
their own backup power systems. On the flip side, it is widely reported that
user traffic did decrease noticeably while power was out.
1.2 AIM
This project aims at resolving the optimisation issues on the current
operational networks with the help of MPLS TE. This report also aims at a
detailed research of the benefits and limitations of MPLS TE technology
focusing on the core networks.
1.3 PROJECT OBJECTIVES

Following objectives are set to achieve the above mentioned aims:
 Investigate and research in TE using literature review.
 Identify the limitations of IP networks.
 Discuss the advantages of MPLS technology over existing
technologies.
 Using a network simulation compare MPLS network against IP
networks.
 Critically evaluate the problems being faced by the current networks,
find an appropriate solution and prove by implementation.
 Take a service provider network and implement TE.
 Conduct analysis and derive results from the simulation.
Figure 1 Research Plan
2.0 A critical review of existing approaches/solutions
OBJECTIVES
CRITICAL REVIEW
& NETWORK EXPERIMENT
DOMAIN
KNOWLEDGE
MPLS AS
TECHNIQUE
RESULTS &
ANALYSIS

In the last few years there have been a lot of changes in the Internet
technology. For example the increase in number of users, implementation of
new devices, applications and services, emergence with other media like TV
and radio. Due to the increasing popularity of the internet worldwide, there
has been problem of network congestion on the internet lines. To solve this
problem service providers and network engineers have been consistently
working on finding new solutions and techniques.
Networks have a fundamental property of multiplexing. Multiplexing is the
process of sharing same network facilities by multiple connections.
Multiplexing can be
• TDM (Time-division Multiplexing)
• WDM (Wave-length division Multiplexing)
• FDM (Frequency-division Multiplexing)
• Statmux (Statistical Multiplexing)
TDM, WDM, FDM are fairly old techniques and are not discussed here.
Statmux is a process of sharing the same bandwidth between all users of
network without dedicating any bandwidth to a particular user. In statmux
service providers can actually sell more bandwidth then actually available
based on the fact that no network user will use their max at all times. In this
report we have critically evaluated existing and the new technologies in terms
of their benefits and shortcomings to fit in the current network requirements.
Mentioned below are some of these statmux technologies used worldwide.
2.1 IP Networks
IP (Internet Protocol) is used for the intercommunication of the packet
switched networks. IP based Networks work on set of Internet Protocol Suite
which is used to determine the path to be used by the data to travel from its
source to destination across multiple networks. IP networks divide the traffic in

to discrete data units called Packets. These packets are then forwarded on
the basis of special algorithm calculations. The two basic functions performed
by IP are addressing and fragmentation. IP uses four different mechanisms to
provide its service. They are Type of Service, Options, Header Checksum and
Time to Live. The commonly used protocols in IP networks are RIP, IGRP,
EIGRP and OSPF. But we have implemented and discussed OSPF because
of its advantages over other protocols.
2.1.1 Benefits of IP
• IP is the most common and very popular protocol.
• IP is highly scalable as it allows easy addition of video cameras,
storage devices and many other devices.
• Cabling and installation is very easy as compared to coaxial cable.
2.1.2 Limitations of IP Networks
• The data communication is not reliable.
• There is no acknowledgement of packet delivery.
• There is no control mechanism for data errors except for Header
Checksum.
• The data flow is uncontrolled and there is no retransmission of data.
http://www.faqs.org/rfcs/rfc791.html
2.2 Open Shortest Path First (OSPF)
Open Shortest Path First (OSPF) was developed by Internet Engineering
Task Force (IETF) in RFC 2328. It belongs to TCP/IP family of protocols.
OSPF is classified as an Interior Gateway Routing Protocol (IGP) because it
is effective for communication within a single Autonomous system (AS).

OSPF calculates route on the basis of SPF or Link State algorithms. OSPF is
a dynamic routing protocol as it immediately detects a network failure and
recalculates new path very quickly. Each OSPF router maintains an identical
Link State database of the AS topology. OSPF divides an AS in to number of
Areas and each area has its own forwarding tables and network topology.
2.2.1 SPF Operation
OSPF is a link state protocol. In case of Link State Protocols all the routers
flood their connectivity information to other network routers. Once a router has
information about other routers, it then runs Dijkstra Shortest Path First
algorithm to calculate the shortest path to other router destinations. Since all
the routers run the same algorithm, every router has the same picture of the
network. Each router keeps a track of its neighbour information, if any network
change takes place the router starts sending LSA to other routers and the
routers then reconstruct a map of entire network topology. SPF operation
helps in fast convergence and less processing power as the network updates
are only send when desired. Thus we have implemented OSPF in our network
model because the ISP network is large and OSPF avoids unnecessary
routing information being sent all over the network all the time which can lead
to degraded performance.
2.2.2 Benefits of OSPF implementation
OSPF has added the following benefits to the network design:
• It is an Open Standards protocol.
• It supports classless routing.
• It divides the whole network in to areas which helps in unnecessary
routing information of various subnets being sent all over the network.

• ISPs have big networks and OSPF can go up to unlimited hops.
• It is a high performance protocol as it detects faults and reroute traffic
very quickly. Thus it has a fast convergence rate.
• Network updates are only sent when a network change occurs rather
than periodically which results in efficient bandwidth usage.
• It also helps in the tagging and routing of external packets send by
different AS.
• It provides better security by the use of password authentication.
• OSPF uses multicast to send updates thus it does not disturb the non
participating routers.
2.2.3 Shortcomings of OSPF
OSPF also has some problems but the problems are relatively minor then the
previous technologies like RIP.
• It consumes major bandwidth initially while sending LSAs.
• It requires more processing power and memory then previous
protocols.
• Router is not able to distinguish the most recent update if two packets
arrive at the same time.
• OSPF also sends unsynchronised updates and makes inconsistent
path decisions.
http://www.isi.edu/in-notes/rfc2328.txt
2.3 Frame Relay Networks
Frame Relay is an efficient data communication technique which operates on
the data link layer and physical layer of the OSI reference model. ISP do not
use frame relay network these days due certain limitations discussed later. It

allows hosts to share network resources dynamically. Two types of devices
are associated with Frame Relay. They are:
• Data terminal equipment (DTEs) - They include terminals, routers, and
bridges.
• Data circuit-terminating equipment (DCEs) - They transmit the data
through the network and are often carrier-owned devices.
Frame Relay networks transfer data using one of the following two connection
types:
• Switched virtual circuits (SVCs) – They are temporary connections,
created for every data transfer individually and then finished after the
data completion.
• Permanent virtual circuits (PVCs) - They are permanent connections
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Fram
e-Relay.html#wp1020734
2.3.1 Advantages of Frame Relay
• It is cheaper than the point to point dedicated lease lines over long
distances.
• Frame Relay provides a Committed Information Rate.
• Customers can use the remote routers already in place thus saves the
cost for new implementation.
2.3.2 Limitations of Frame Relay

We have not used frame relay technology in the experiment because of the
following reasons:
• Frame Relay provides CIR (Committed Information Rate) which is not
desired by ISP in all SLA (Service Level Agreement).
• It assures less quality of service as compared to other protocols
because FR uses variable length packets.
• Since all the customer use the same network to transmit data, at times
there can be network congestion.
• There is single point of failure at the host site. If the host site goes
down whole network goes down.
2.4 ATM Networks
ATM (Asynchronous Transfer Mode) is implemented as a network protocol. It
is also a very good option of network engineering after MPLS. In ATM
networks data travels in the form of fixed size cells for multiple services like
voice, video. The figure below is a basic ATM network structure. An ATM
network consists of ATM switch and ATM network endpoints. An ATM switch
accepts the cells from the ATM endpoints, update the cell header information
and forward cell towards its destination via outgoing interface.

Figure 2 An ATM Network
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/atm_f
iles/atm-03.jpg
2.4.1 Advantages of ATM
• ATM networks are connection oriented which means the delivery of the
cells is guaranteed.
• ATM allows multiple services across the same network.
• ATM offers better quality of service then IP networks because all the
data packets are of fixed size.
2.4.2 Issues in ATM Networks
In spite of all the above mentioned features, ATM has few drawbacks which
prevented us from using ATM on the network design.
• Cell loss in data transmission results in data corruption which is not
desired by ISP.

• A new ATM setup requires expensive ATM hardware and software.
Thus it is expensive.
• ATM carries all the services through the same network facilities but
there are better technologies then ATM for specific services.
• Large ATM networks are very complex as compared to IP networks.
• ATM cell size is really tiny as compared to large IP packets. Small cell
size was chosen because of the low-bandwidth links initially used but
now with the fast links, large IP packets are better compatible.
• ATM networks work on the principle of constant bit rate which no
longer exists as the compressed video streams travel with variable bit
rate.
• ATM doesn’t merge well with other technologies like IP so there is a
compatibility problem.
• ATM networks are a full mesh topology which is not desired by ISPs.
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/atm.h
tml
2.5 Traffic Engineering
Traffic Engineering deals with the management of network traffic to fit the
network resources. TE is a special branch of engineering which deals with
issues related to performance of networks. TE involves application of various
technologies for steady network traffic, enhanced reliability, network capacity
management, improved data security, fast data transfer and efficient use of
network resources. The aim of TE is to increase network performance
efficiency in terms of resource utilisation and congestion control. This is
achieved by closely monitoring the network traffic process and effective
utilisation of network resources. The performance of the network is measured
by packet loss, delay variation, latency and throughput. Path selection is a
crucial step in effective and efficient data communication. TE helps in the

selection of best suitable path for the moment of data. In IP networks the path
selection is done on the basis of destination-based forwarding. But if there is
an unpredictable failure on the operational network, data starts using the
alternative path available but this new path very soon becomes over
congested. In order to evenly distribute the extra traffic over the free links, TE
is implemented. Traffic Engineering simply is moving the traffic load from the
congested links over to the free links to avoid drops, jitters and latency. TE
along with MPLS is an excellent solution to network traffic management.
Fish Problem
The concept of Traffic Engineering can be easily illustrated using the common
Fish problem.
Figure 3 The Fish problem
Definitive MPLS Network Designs (by Jim Guichard; François Le Faucheur;
Jean-Philippe Vasseur)

The figure above demonstrates a common fish structured problem on the
networks. In the figure above the data travelling from R1  R5 or R6  R5
has two path choices:
1) R2  R3  R4
2) R2  R7  R8  R4
Assume that all the links are OC-3, 155mb/s approx. Also assume that R1 will
send 120mb/s to R5 and R6 will send 60mb/s data to R5 on an average. By
default all the data from R1 and R6 will take the shortest path R2  R3  R4
because it is the low cost path. On this path R2 tries to send 180mb/s
whereas the link capacity is 155mbp/s, packets start dropping on an average
of 25mb/s. This path becomes over congested very soon.
To solve this problem we can change the IP metric on the other path but then
all the traffic would start using the alternate path causing congestion on it. So
it still does not solve the problem. Another solution can be to set equal cost for
both paths, this way the problem would be solved but this method does not
work well for large and complex networks. This problem can be solved by
applying Traffic Engineering capabilities to IP networks. TE allows the extra
traffic to use the alternative path. Thus it saves the packet drops and helps in
effective resource utilisation.
Definitive MPLS Network Designs (by Jim Guichard; François Le Faucheur;
Jean-Philippe Vasseur)

Multiprotocol Label Switching
As discussed earlier in the destination based packet forwarding, path is
calculated at each hop router, thus it is very time consuming and highly
processor intensive. In MPLS packets are forwarded on the basis of label
information, thus it consumes less time and processor. So MPLS started in
around late 1990s. MPLS serves as a standard technology base for various
protocols which increases the scalability and scope of layer 3 forwarding. The
reason behind such a technology was not high packet transfer rate or better
price because the 20-bit label lookup is not very fast then the 32-bit IP
address lookup. So the actual reason behind MPLS is the applications and
services it supports. They are:
MPLS TE (MPLS Traffic Engineering)
MPLS TE combines best of traffic engineering capabilities of ATM and
flexibility of IP. MPLS TE builds LSPs (Label Switched Paths) or TE Tunnels
between two nodes and forward packets on the basis of label attached to the
packet irrespective of the actual content of the data. The head end of the
tunnels controls the flow of the traffic. Also resource reservation can be done
for a steady flow of data.
MPLS VPN (MPLS Virtual Private Network)
VPNs are used to connect different client sites over public or shared IP
networks via leased lines, frame relay or ATM PVCs. MPLS with VPN help in
solving the problems of overlapping IP addresses, private IP, intranets,
extranets and internet connectivity. MPLS adds scalability to the VPNs.
MPLS QoS (MPLS Quality of Service)

MPLS maintains 3 bits in the MPLS header of the packet for the class of
service. These bits are called EXP (Experimental) bits and mostly carry
information same as that of the IP Precedence.
AToM (Any Transport over MPLS)
MPLS helps in carrying the layer 2 traffic such as Ethernet, Frame Relay and
ATM over MPLS cloud. In case of ISP, MPLS helps in creating remote POPs
(Point of Presence) for point to point connectivity with the remote access
points.
ATM MPLS TE
ATM forwards cells. MPLS TE forwards packets.
Core Network Topology is not
visible to edge routers.
Network Topology is advertised
by IP routing protocols.
ATM requires a full mesh
topology.
MPLS TE does not require a full
mesh topology.
Table 1 Difference between ATM and MPLS TE
(Traffic engineering with MPLS By Eric Osborne, Ajay Simha)
MPLS Operational Concept

MPLS can either operate in frame mode in case of IP networks or a cell mode
in ATM networks. When an IP packet enters the MPLS core, it is assigned
with a label on the top. The following hops then forward these packets only on
the basis of label information. This avoids the unnecessary path calculation at
each hop saving time and cost. There can two or more labels attached to a
packet on the basis of destination. All labels attached to a packet make, what
is called a Label Stack. At every hop only the outermost label is considered.
Thus the hops have nothing to do with inner labels. The path which a labelled
packet will follow is called a LSP (Label Switched Path). When a packet
reaches MPLS router it examines the label against its forwarding database,
after that router determines the outgoing interface and the outgoing label to be
used. Finally it swaps the existing label with the outgoing label and sends it
through the outgoing interface. This process is called label swapping. Label
involves three fundamental actions of push/impose, swap, pop/dispose.
Figure 4 Basic MPLS Concept
http://www.interpeak.com/products/mpls.html
Firstly routers exchange the IP based information with the help of IGP
protocols such as OSPF. Secondly unique labels are generated at random by
the LSRs and are stored in LIB. These labels are then forwarded to neighbour

routers to form LSP. This information is stored in FIB. LFIB enables Label
switching. Every LSR builds an LIB, FIB and LFIB.
MPLS Label
MPLS technology is based on the label mechanism. A 32 bit label field
consists of 20 bit label, 3 bit experimental field normally used to hold QOS, 1
S bit to indicate where the bottom of label stack is and 8 bits for the time to
live (TTL) and is decremented at every hop to avoid routing loops.
Figure 4 MPLS header packet structure
http://rodneyrbts.files.wordpress.com/2009/03/030209-0006-mpls2.png
Label value can be anything between 16 and 1,048,575 (label field 20 bit so
2²º max value). The label values 0 to 15 have been reserved. A value of 0
represents the "IPv4 Explicit NULL Label", value of 1 represents the "Router

Alert Label", value of 2 represents the "IPv6 Explicit NULL Label" and value of
3 represents the "Implicit NULL Label".
MPLS Components
MPLS technology comprises of two major components:
• Control Plane – This is where all the routing information and control
information like label binding is exchanged. It contains ALL Layer 3
routing information to include the processes involved with the operation
of routing protocols (OSPF, BGP, RSVP, etc.). It also includes any
information responsible for updates between neighboring routers like
Tag or Label distribution information exchange.
• Data Plane – In data plane actual forwarding of data packet takes
place. The information in the data plane like specific Tag or Label
numbers for a specific prefix is completely dependent on the Control
Plane. So, the mapping of IP destination networks to labels gets copied
to the Data Plane, thus at a Layer 2 level is able to be switched. It
eliminates the need of a Layer 3 lookup, saving time and cost.

Figure 5 MPLS Control Plane Data Plane
http://www.notquiteleet.com/MPLS_control_data_plane.gif
LIB, FIB and LFIB in MPLS
MPLS uses a set of tables to forward packets. LIB, FIB and LFIB have
specific roles in MPLS packet forwarding.
• LIB – LIB is Label Information Base. LIB is a table which stores label
bindings information learned from LDP (Label Distribution Protocol).
• LFIB – Label Forwarding Information Base is a table to forward labelled
packets. LFIB contains information of ingress and egress routers like
outgoing interface, outgoing label etc learned by LDP. It helps in MPLS
forwarding.
• FIB – Forwarding Information Base consists of the information received
by Layer 3 protocols such as OSPF. When an unlabelled packet

reaches ingress router it is forwarded on the basis of layer 3 header by
an FIB table lookup. It helps in IP forwarding.
Label Distribution
After the LSR generate labels. It uses two ways to distribute them:
• Ordered LSP Control mode – LSR waits to receive the binding
information from the downstream neighbor before forwarding it to the
upstream neighbors. MPLS uses ordered control mode in cell mode
networks and RSVP.
• Independent LSP Control Mode – LSR freely distribute label bindings
to all upstream and downstream neighbours without waiting to receive
binding information from downstream neighbours. Independent mode is
used in frame based networks.
Traffic engineering with MPLS By Eric Osborne, Ajay Simha)
Downstream on Demand and Unsolicited Downstream
LDP exchanges subnet/label bindings using one of two methods: downstream
unsolicited distribution or downstream-on-demand distribution. Both LSRs
must agree as to which mode to use.
Downstream unsolicited distribution disperses labels if a downstream LSR
needs to establish a new binding with its neighbouring upstream LSR. For
example, an edge LSR may enable a new interface with another subnet. The
LSR then announces to the upstream router a binding to reach this network.
In downstream-on-demand distribution, on the other hand, a downstream LSR
sends a binding upstream only if the upstream LSR requests it. For each

route in its route table, the LSR identifies the next hop for that route. It then
issues a request (via LDP) to the next hop for a label binding for that route.
When the next hop receives the request, it allocates a label, creates an entry
in its LFIB with the incoming label set to the allocated label, and then returns
the binding between the (incoming) label and the route to the LSR that sent
the original request. When the LSR receives the binding information, the LSR
creates an entry in its LFIB and sets the outgoing label in the entry to the
value received from the next hop.
www.cisco.com
LDP major functions
• Neighbour discovery
• Session establishment and maintenance
• Label advertisement
• Notification
Benefits of MPLS
MPLS is currently being used by most of the large service providers. MPLS
has been implemented in the network design and suggested as a problem to
the current network problems due to the following reasons:
• MPLS helps in decoupling of routing and forwarding as the packets are
forwarded on the basis of label rather than IP header information.
• It is base for the NGN (Next Generation Services) such as VPN and
TE. These applications are used by the ISPs on their real networks.

• MPLS also helps in bridging the gap between IP and ATM technologies
by using LC-ATM (Label Controlled ATM).
• Packet forwarding is faster as it is based on packets and packet
classification is only done at the ingress router.
• MPLS VPN is the most common and popular method of connecting
remote locations over public or SP networks.
• MPLS core is hidden from the outside world which increases the
security and reliability of SP network.
How MPLS TE works
MPLS TE functionality involves three basic steps:
Information Distribution
Information distribution involves what information is distributed, when is it
distributed and how is it distributed. It also involves the configuration of
information, ways to avoid traffic flooding and protocol specific details.
Following attributes are distributed:
• Available bandwidth per interface.
• Available weight per interface.
• Available flags per interface.

MPLS TE Implementation Consideration
MPLS TE has the following major advantages, for which it has been
implemented in the network experiment:
• MPLS TE strategic design is used to build a full mesh network design.
In a full mesh LSPs automatically work out the best way to avoid any
possible congestion.
• MPLS TE has a special feature of FRR (Fast Reroute) which
automatically detects and quickly repairs any failure on the network.
• MPLS TE is also used in a tactical design where in traffic is moved
over from over congested links to the free links as and when desired.
We have used Tactical design in the network experiment because ISPs
have to move traffic according to the client requirements.

3.0 Research Methodology and Analysis
Research methodology is a study of how research is done scientifically. It
helps in solving the problem systematically and is a full expiation of the project
and the product. There are different approaches to research.
Qualitative Approach – It involves the insight of the problem and focuses on
the quality or kind of the project.
Quantitative Approach – This approach involves measurement and
expression of quantity in numeral terms.

In the research we have used both the approaches. Firstly we have done a
review of the existing technologies to gain in depth knowledge of the problem.
From the knowledge gained a network experiment has been conducted in a
simulated environment to get statistical results and solution.
3.1 Devices used in the industry
ISPs are using a variety of routers depending on their requirements. Routers
commonly used in the core are mentioned below. All these routers have
special capabilities for the VPN, security, Network Management and QoS.
3.1.1 Cisco 7000 (7200,7300,7500,7600) series
These devices are extremely powerful and highly scalable with a forwarding
speed of 110,000 packets-per-second. They have a higher reliability then the
previous versions and also provide facility of hot-swappable line cards, and
flash memory-based storage to easily update software images. The 7200
series chassis consists of the 2−slot Cisco 7202, the 4−slot Cisco 7204 and
Cisco 7204VXR, and the 6−slot Cisco 7206 and Cisco 7206VXR.
3.1.2 Cisco Gigabit Switched Router/GSR (10000 and 12000
Cisco series)
Cisco 10700 is a two slot router offering differentiated services at optical
speeds of OC-48/STM-16. Cisco 10000 series is an eight slot Gigabit

Ethernet Switch and has a special card for OC-48 WAN link. They offer MPLS
VPN, IPSec and QoS capabilities. Cisco 12000 series is yet another powerful
range of routers. They have 6/15 slots and 40Gb per Ethernet slot and has
special cards for OC-48 and OC-192 WAN links.
3.1.3 Edge Switch Router (ESR)
ESR is again a powerful Cisco router which supports STM-4 POS module. ESR
support NGN (next generation networks), MPLS VPN and any transport over MPLS
(ATOM). AToM services are ATM AAL and cell relay, VPLS, VLAN, Ethernet, Frame
relay, HDLC, PPP, tunnel selection.
3.1.4 Cisco CRS-1 series
This is the king Cisco series. It has got 8 to 16 slots. Also has the latest Cisco
IOS XR software and has the support for OC-768. The IOS is self healing and
self defending. It offers terabit speeds.
3.2 Case Study
We have undertaken the case study of the backbone network of Tulip
Telecom Limited (India). Tulip Telecom Limited is a data telecom service and
IT solutions provider that offers innovative IP based infrastructural solutions to
its customers. Tulip is India’s largest MPLS VPN player and has been the
front-runner in provisioning and managing multi location wide area networks
for various industry verticals. Tulip is a public limited company and is listed on
the Bombay Stock Exchange and National Stock Exchange in India. The
company has displayed robust growth since its inception and its IPO has been
ranked as one of the top four IPO's in India, since 2005, by CNBC. With
revenues in excess of Rs 1614.40 Crores (USD 322 Million) in the financial
year ending 31st March, 2009 and a market capitalization in excess of Rs.

2131.50 Crores (USD 426 Million as on 31st March 2009), Tulip is one of the
largest corporate in its domain.
http://www.tulip.net/AboutUs/Companyprofile.htm
3.2.1 Delivery
• 1500+ certified engineers.
• Cisco Gold partnership and robust alliances.
• ISO 20000-1 & 27001 based processes.
3.2.2 Network
• 1415 cities.
• More than 4000 Points of Presence.
• 180 support centers.
• STM 16 based core backbone.
• Redundant Multicarrier Network.
• Metro Ether net based access network.
• WiMAX & Advanced WiFi based wireless access technologies.
• IP NGN tested with major BTS players
3.2.3 Data Centers
• A potential capacity of 100,000 sq feet.
• Only provider to have termination from all telcos.
• Ready to use NGN head
3.2.4 Services running in Tulip:
• OSPF

• BGP
• LDP
• MPLS – L2/L3
• Metro Ethernet/SDH
• VPDN
• MVPN
• QoS
• ISDN
3.2.5 Protocols running with customers:
• EIGRP
• OSPF
• BGP
• RIP

Figure 2 Tulip Core Network
http://www.tulip.net/AboutUs/Companyprofile.htm
Figure 2 above shows the real time core network of the company all across
India. A core network is a backbone network, usually with a mesh topology,
that provides any-to-any connections among devices on the network. While
the Internet could be considered a giant core network which consists of many
service providers that run their own core networks and those core networks
are interconnected. We have simulated the above network design on GNS3
with 9 router locations because it was no possible to run more then nine
Core Network Design
Data Center
High Capacity Fiber
Point to Point
Wireless
Central NOC in New Delhi
Redundant NOC in Mumbai
Regional NOC’s
in all Class B cities
ISDN RAS in all Class
A & B Cities
MumbaiMumbai
DelhiDelhi
AA
BB
CC
DD
PunePune
AhmedabadAhmedabad ChennaiChennai
BangaloreBangalore
HyderabadHyderabad
KochiKochi
ChandigarhChandigarh
BhopalBhopalKolkataKolkata
LucknowLucknow
Rural
network

routers on GNS3 (graphical version of Dynagen) as it needs very high end
CPU and huge memory. So due to the shortage of resources the experiment
design looks different then the real scenario. They are using 3-tier
architecture. The company has a large network with over 4000 POPs all
across India. They are using OSPF, MP-BGP, MPLS TE technologies on their
operational networks. The company has over 3000 clients including Barclays,
ICICI Bank, AT&T, Bombay Stock Exchange, DHL, SONY, Sanyo, Philips and
many more. The report is virtual model of the actual design. A private
addressing scheme has been implemented as the company’s real time
network information could not be used due to SLA (Service Level
Agreements) with the clients.

Figure 3 Network Design (Diagram made by DIA)
Figure 3 depicts the core network of the company. Multiple routers have been
used in a single location for redundancy purposes. In the figure the topology
used is a 3-tier topology. Data travel across P  PE  CE routers. The
real time links are DS3 ether net links with a capacity of 45mbps. Every
redundant link is ½ DS3 Ethernet with bandwidth of 22.5mbps. But in the
experiment we have used T1 serial links to connect sites. An IP address of
172.16.0.0/16 has been chosen for the experiment. The IP addressing

scheme is designed according to 1918 RFC standard. In the real time
network, company is using 7200 series, 7600 series and GSR routers but as
the images of these routers are not easily available for testing purposes so
alternatively we have used 3640 routers, IOS image version 12.4. The
company is a gold partner of Cisco and is allowed to use the image for testing
purposes. This network design has been made in the Delhi site location of the
company with consistent monitoring of the real time network. Real time
problems of ISP along with their solutions have been produced in the report.
Problems have been discussed with MPLS SME (Subject Matter Expert) and
solutions have been put down on the thesis.
3.3 IP Addressing Scheme
Scalability is an important criterion while designing a network. A design
solution should be well scalable and should discuss the limitation and factors
affecting the scalability. In the network experiment IP addresses have been
assigned to the interfaces for testing purposes with reference to RFC1918
(Address Allocation for Private Internets). All the routers are connected using
serial T1 links. Free private IP range of 172.16.0.0/16 has been used as per
IANA (Internet Assign Number Authority). It has been further divided in to 256
subnets of 172.16.0.0/24, 172.16.1.0/24 and so on up to 172.16.255.0/24.
Each one of these subnets is further divided in to 64 sub networks as
172.16.0.0/30, 172.16.0.4/30 and so on up to 172.16.255.252/30. And each of
these subnets has 2 usable IP addresses as 172.16.0.1, 172.16.0.2 with
172.16.0.3 as the broadcast address up till 172.16.255.254/30 which is the
last usable IP address of the last subnet.

Sites/
Link Type
Network
address
Broadcast
address
First address Last address
Ahmadabad-
New Delhi2 /
T1
172.16.1.0 /30 172.16.1.3 /30 172.16.1.1 /30
S0/1
Ahmadabad
172.16.1.2 /30
S0/1
New Delhi 2
Ahmadabad
- Mumbai1 /
T1
172.16.1.4/30 172.16.1.7/30 172.16.1.5/30
S0/0
Ahmadabad
172.16.1.6/30
S0/0
Mumbai 1
Hyderabad -
New Delhi1 /
T1
172.16.1.8/30 172.16.1.11/30 172.16.1.9/30
S0/0
Hyderabad
172.16.1.10/30
S0/0
New Delhi1
Hyderabad –
Mumbai2 /
T1
172.16.1.12/30 172.16.1.15/30 172.16.1.13/30
S0/1
Hyderabad
172.16.1.14/30
S0/1
Mumbai2
Hyderabad –
Mumbai3 /
T1
172.16.1.16/30 172.16.1.19/30 172.16.1.17/30
S0/2
Hyderabad
172.16.1.18/30
S0/2
Mumbai3
Mumbai3 -
Mumbai2 /
T1
172.16.1.20/30 172.16.1.23/30 172.16.1.21/30
S0/3
Mumbai3
172.16.1.22/30
S0/3
Mumbai2
Mumbai2 –
Mumbai1 /
T1
172.16.1.24/30 172.16.1.27/30 172.16.1.25/30
S0/2
Mumbai2
172.16.1.26/30
S0/2
Mumbai1
Mumbai1 -
New Delhi1 /
T1
172.16.1.28/30 172.16.1.31/30 172.16.1.29/30
S0/1
Mumbai1
172.16.1.30/30
S0/1
New Delhi1
New Delhi1 -
New Delhi2 /
T1
172.16.1.32/30 172.16.1.35/30 172.16.1.33/30
S0/2
New Delhi1
172.16.1.34/30
S0/2
New Delhi2
New Delhi2 -
Mumbai2 /
T1
172.16.1.36/30 172.16.1.39/30 172.16.1.37/30
S0/0
New Delhi2
172.16.1.38/30
S0/0
Mumbai2
Chandigarh
– NewDelhi /
T1
172.16.1.40/30 172.16.1.43/30 172.16.1.41/30
S0/3
Chandigarh
172.16.1.42/30
S0/3
NewDelhi
Mumbai 1 –
Pune / T1
172.16.1.44/30 172.16.1.47/30 172.16.1.45/30
S0/3
Mumbai 1
172.16.1.46/30
S0/3
Pune

Table 1 WAN Links
Loop back addresses have been used at all the routers because The loop
back interface provides a stable address for protocols to use so that they can
avoid any impact if a physical interface goes down.
Router Location Loop back Address
New Delhi 1 172.16.100.1
New Delhi 2 172.16.100.2
Mumbai 1 172.16.100.3
Mumbai 2 172.16.100.4
Mumbai 3 172.16.100.5
Hyderabad 172.16.100.6
Ahemdabad 172.16.100.7
Chandigarh 172.16.100.8
Pune 172.16.100.9
Table 2 Loop back addresses
3.4 Analysis of the Network Design
In this section the design is explained in detail. What technologies are used
and how the network is designed. How the traffic has been managed by TE
on the basis of its various attributes.

• This model is the case study of the actual ISP network so the results
are 100 %. GNS3, a graphical version of dynagen has been used due
to the limitations, explained previously.
• OSPF is being used in the core network because OSPF has fast
convergence rate and divides huge ISP network in to small areas, thus
decreasing the size of router forwarding tables so less CPU is required
which results in high performance. OSPF can manage up to 50 routers
in a single area.
• The core consists of 3640 routers. TE is enabled on the core for the
Provider routers and MPLS is enabled on the PE and P routers.
• ISP is not using TE all the time. They only implement at the time
congestion occurs because they want to route the traffic according to
the requirements.
• In the experiment we have used a Tactical MPLS TE design where in
LSP (Label Switched Paths) are setup as per desired to solve traffic
congestion. Strategic TE model is not used because the fully mesh
topology is not practically possible in real scenarios.
• Traffic Engineering tunnels have been implemented. RSVP has been
implemented for signalling and bandwidth reservation purposes.
• Router IDs are configured on each router. Router Id helps the
neighbour router to form adjacencies with each other. By default the
highest IP address of any interface is chosen.
• Customer sites communicate with each other with help of MP-iBGP
which is discussed in the later section of the report.
• MPLS TE technology has been implemented to route traffic in the core
after analysing the problem of network congestion on the real ISP
network. Appropriate snapshots have been captured for the detailed
explanation of the problem situation and solutions.

3.5 Testing Outputs
Following are the results obtained from the simulated operational network
over Dynagen. Full router configurations are pasted in appendices. These
snapshots explain the operation of various technologies like OSPF, MPLS,
TE, MP-iBGP, LSP, VRF, Tunnelling and load sharing using different
commands and attributes. Snapshots have been captured randomly from
some of the routers as the results are same on all the routers. These
snapshots also prove the results obtained from critical review of the
technologies.
3.5.1 IGP OSPF Protocol

Figure 4 Show IP Protocols
Figure 4 shows that OSPF has been implemented on the SP cloud. This
command tells about all the known networks and subnets. It also shows the
routing timer. The administrative distance is 110 by default and it can be
changed as per requirements.
Figure 6 Show IP OSPF

Figure 6 shows the details of the OSPF protocol. Router id of the Delhi1 and
it’s a part of the Backbone area 0. The router id used is the same as its loop
back address because it is never down. Thus helps in easy troubleshooting.
Figure 7 OSPF Neighbours
Figure 7 shows the adjacent OSPF neighbours with their current states.
Figure 8

Figure 8 shows the directly connected routes and dynamically learnt OSPF
routes. Thus the network is a fully converged network.
3.5.2 MPLS Snapshots
Figure 9
Figure 9 shows that MPLS has been enabled and is using the Label
Distribution Protocol. Tunnel status is no which shows that TE is not
implemented yet but when TE commands will be enabled the tunnel status will
be yes.
Figure 10
Figure 10 shows that the ldp discovery is happening on directly connected
serial interfaces and it is receiving and transmitting the ldp announcements
from the adjacent neighbours. This command is very useful in term of

troubleshooting. If it is showing xmit not recv, it means the adjacent neighbour
is not sending any announcements.
Figure 11
Figure 11 shows about the minimum and maximum label information and this
is the default range of labels provided. With addition to this it let us know
about the hello and hold time interval. If the hello and hold time interval is not
matching on the adjacent peers, LDP might not come up.

Figure 12
Figure 12 shows about the information of the adjacent neighbours. Local LDP
Ident is the LDP router ID of the local router and the Peer LDP Ident is the
remote peer LDP router ID. Total three LDP sessions are established.
Figure 13
Figure 13 shows about the LFIB (Label Forwarding Information Base) where
in outgoings labels are mapped with the outgoing interfaces. Local tag are the
labels which are generated by the router locally and these labels become the
remote labels for other peers. Outgoing tags means when ever the packet

forwarding happen push the particular label for it's respective destination.POP
tag means remove the IGP label before forwarding.
Figure 14
Figure 14 shows about the detailed information of 172.16.100.5 route. It is
explicitly stating that label 22 is generating by router locally and label 22,22,16
are receiving from the remote peers.
3.5.3 Traffic Engineering

Figure 19 Static Tunnel
The figure above shows that a static route has been created to avoid
congestion over the NewDelhi2  Mumbai2 link. Static TE is implemented
when SP wants to route the traffic of a specific subnet like web server, voice
or FTP through the tunnel. It is the easiest method but not always
recommended.
Figure 20 Tunnel Brief
The figure above shows that LSP is up and running, RSVP signalling is
running and the tunnel’s destination is 172.16.100.7.

Figure
The above figure shows that RSVP allocation of bandwidth along the path
which is of 200 kbps. If the RSVP mentioned bandwidth is not available along
the path, the TE tunnel will never come up. The path along with individual
hops is clearly visible.

Figure 20 Explicit path
The figure above shows that a tunnel 10 was made explicitly to Mumbai 2
because after link failure between Ahemdabad --> Mumbai1, the traffic of
Ahemdabad which was supposed to go to Mumbai 2 started going through
Ahemdabad --> NewDelhi2 --> Mumbai2 which made the link from Newdelhi2
--> Mumbai2 over congested . Thus the explicit route was defined as
Ahemdabad --> NewDelhi2 --> NewDelhi1 --> Hyderabad --> Mumbai2. All
the traffic by default selects Path1 and goes through tunnel and if there is a
problem on the Path 1 then traffic automatically goes to Path 2 which is
dynamically calculated by OSPF. (Refer to Figure 3 Simulated Network
Design). Explicit path means that the data will always be forwarded through
the manually defined path rather than dynamic.

Figure 21 IP routes learned through tunnel10
The figure above shows auto route has been announced and the traffic
destined to Mumbai network will go through the tunnel. The routes shown
above are connected through tunnel 10.

Figure 22 Dynamic Path Option
Dynamic Path option has been chosen with auto route enabled. Outgoing
label used is 18. RSVP signalling tells us about the explicit path where RSVP
signalling is enabled.

Figure 23 TE untagged labels
The figure above shows that after the implementation of TE on the network,
all the traffic from Ahemdabad destined to Mumbai network 172.16.1.24 will
automatically go through the tunnel which acts as a point to point link.
Outgoing traffic is untagged because at the interface T10 all the labels are
taken off the packet and its forwarded on to tunnel10.
3.5.4 Load Sharing
Figure 5 per destination based sharing
Figure 5 shows that IP CEF (Cisco Express Forwarding) has been enabled.
The packets are being shared on two interfaces S0 and S1 on destination
basis where the destination label is same.

Figure 24 Equal OSPF Cost Tunnelling
When the problem was fixed the SP thought of sharing the traffic to avoid
future problems. In the figure above it is clearly visible two tunnels have been
created to Mumbai2 (172.16.100.4) to share traffic load.
Figure 25 Equal Share Count

The figure shows that TE calculates its cost from IGP metric and shares equal
load on both tunnels. OSPF route metric is 52 for both tunnels.
Figure 26 Equal load sharing ratio 1:1 via CEF algorithm
The picture above shows that internal CEF hash algorithm which is of 4 bits. It
shows that each packet will move across each tunnel with label 18 and 21
respectively. Thus the load sharing ratio is 1:1.

Figure 27 Per Destination load sharing
The figure above shows equal load sharing on basis of destination
172.16.100.5. Its not recommended but used as per requirements. It is
clearly visible packets are flowing one by one through each interface s0/1 and
s0/0 respectively.
Unequal Cost Load Balancing With MPLS Traffic Engineering
BGP and EIGRP are the only protocols that support load balancing across
unequal cost paths. Variance is used in EIGRP and BGP attributes help in
BGP. The same functionality is added in TE also.
Figure 27 Unequal load sharing

The figure above shows share count that ratio of 1:2. Thus there is unequal
load sharing on both the tunnels.
Figure 28 CEF showing unequal load sharing
The figure above shows tunnel 50 is up 5 times and the tunnel 10 is up 10
times. CEF hash algorithm shows the load distribution. The traffic share on
tunnel 10 is twice the traffic share on tunnel 50.

3.5.5 TE Metrics
Figure 29 Auto bandwidth disabled
The above figure shows that auto bandwidth feature is disabled. This is the
default mechanism of Cisco IOS. It is recommended to enable auto bandwidth
to manage link utilization.

Figure 30 Auto bandwidth allocated
The figure above shows that auto bandwidth is enabled on the tunnel and the
timer is set to 300 seconds. By default the band width allocated is zero, when
the traffic starts flowing from the link the bandwidth is automatically configured
on the specific link. The requested bandwidth is 100 kbps and after 300
seconds auto bandwidth will go up to 100 kbps. 190 is the timer which is
decreasing when it will reach to 0, auto bandwidth will calculate the tunnel
stats again.

Figure 31
If information of bandwidth is not flooded on time, it may cause lot of problems
in the network. MPLS TE has a reason to flood the significant information of
link bandwidth in network, so that TE tunnel should come to know which
tunnel is free to forward the traffic. Threshold is the parameter which helps
network administrator to set the up and down values.
The above figure shows that the physical bandwidth is 1544 Kbps and RSVP
is using 200 Kbps out of the total. The threshold value is set to 15% in up or
down so if any of the link bandwidth changed below that threshold there will
be no flooding and the flooding will take place only after the timer expires.

Figure 32 Tunnel Priority
In service provider network, where a single destination has various path and
because of the high availability of destination, network engineers create
different tunnels through different paths and every tunnel path is set with
priority. The priority is 3 bit values varies from 0 – 7. Higher the number lowest
the priority is. Tunnels are called according to the priority level. In Cisco IOS
tunnels priority is always more than the hold value.
Figure 33 TE Metric

The above figure shows that TE metric will used over IGP metric in the TE
advertisements, by default cost of TE metric is same as the cost of IGP. But it
can be changed to route traffic as per requirements. Higher the administrative
weight lower will be the path preference. TE metric has been used to
configure alternative link (Ahemdabad → Delhi 2 → Delhi 1 –> Hyderabad →
Mumbai 2 → Mumbai 1) to Mumbai locations as primary by increasing the
administrative weight of the main link (Ahemdabad → Mumbai1).
Administrative weight need to be configured under interface, if not configured
TE will announce the same cost as of IGP.
Figure 34 Administrative Weight or Metric
The figure above shows that administrative weight on the S0/1 interface is set
to 400 because of which this path will be preferred over Ahemdabad 
Mumbai2 link. Also it is visible that though the OSPF cost is more on this link
but TE advertisements consider the TE metric and route the traffic through
this link.
3.5.6 Link Management Control

Figure 35 Link Management admission control
The figure above shows all the LSP known by Link Manager. The state Resv
Admitted shows that a reservation of this tunnel has been sent and everything
is good. The R on the extreme right means that bandwidth has been reserved
and G means bandwidth has been reserved from the global pool.
Figure 36 Link Management Bandwidth Allocation
The figure above shows the bandwidth allocated on the links. BW HELD
means that bandwidth has been held for a path request temporarily before
being Resv.

Figure 37 Show Link Management Interfaces
The figure above shows the TE link stats, maximum bandwidth available and
the bandwidth reserved, inbound and outbound admission control, admin
weight metric and the neighbour information as well.

Figure 38 Link Management Summary
Figure 38 shows the summary of all the link information. It also shows much
of the same information as the previous commands.

3.5.7 Creating VRF (Virtual Route Forwarding)
Figure 41 VRF Interfaces - Chd
The figure above shows VRF A& B is created on PE Chandigarh. The vrfs are
created because both customers want to use the same ip scheme. For
simulation purposes we have created loopbacks which depicts about the
customer edge(CE) information and a part of respective vrfs.
Figure 42 VRF Interfaces - Pune
The above figure shows Pune(PE) which is directly connected to Mumbai 1(P)
router. The two vrfs created named A & B and after successful
implementation of MP-iBGP both vrfs able to communicate each other.

Figure 43 MP iBGP Neighbour
The figure above shows the BGP neighbour 172.16.100.9 which is the site
Pune (PE). The neighbour PE is in the same AS (Autonomous System) and is
forwarding two routes.
Figure 44 Routes of vrf A & B
The figure above shows about the routes received through MP-iBGP for vrf A
& B.
Figure 45 Forwarding table for VRF routes
The figure above shows that for destination 192.168.1.2 aggregate label is
used. V stands for VPN routes.

Figure 46 Ping VRF A
The figure above shows end to end VPN connectivity of customer A where in
192.168.1.1 is the loop back configured on Pune (PE) under VRF A
Figure 47 Trace route of VRF A
The figure above shows trace route of VRF A which depicts the label 24 of
route 192.168.1.1 and the label is preserved across the network.

4.0 Discussion of Problems on real life networks
In a meeting with the MPLS (Subject Matter Expert), we discussed the
problems faced by company on their network and why they implemented
MPLS TE on their network. The problems were as follows:
4.1 Mux failure
In telecommunications, a multiplexer or mux is a device that combines several
input information signals into one output signal, which carries several
communication channels, by means of some multiplex technique. MUX is a
point of contact of all the fiber links from where the various types of services
offered. The MUX located at Mumbai1 location failed due to firmware issue
and due to which wan links connecting NewDelhi1-> Mumbai1 and
Ahmedabad → Mumbai1 failed. As a consequence of this problem, the traffic
of NewDelhi1 which was supposed to reach Mumbai1 was rerouted through a
new path NewDelhi1 → NewDelhi2 → Mumbai2 → Mumbai1 as calculated by
SPF algorithm and at the same time entire traffic of Ahemdabad also followed
the same path i.e. Ahmedabad → Delhi2 → Mumbai2 → Mumbai1. As
explained previously, Link New Delhi2 → Mumbai2 which was already fully
utilised by its own traffic could not handle more traffic. Thus this link got
congested and the packets started dropping. Following is the depiction of the
problem through figures.
Figure 15 Traffic through NewDelhi1  Mumbai1 before link failure

The figure above shows before the link failure the traffic is flowing from
NewDelhi1 to Mumbai1 directly via path 172.16.1.29  172.16.100.3.
Figure 16 Traffic routed by OSPF after link failure
The figure above shows that after the mux failure at Mumbai 1 the serial links
from Mumbai1 → NewDelhi1 failed, So the traffic changed its path via
NewDelhi1  NewDelhi2 (172.16.1.34)  Mumbai2 (172.16.1.38) 
Mumbai1(172.16.1.26) because of OSPF. (Refer to Network Design). Now the
new route caused congestion on the NewDelhi2  Mumbai2 link as it already
had its own traffic on the link.
Figure 17 Traffic through Ahmadabad  Mumbai1 before link failure
The figure above shows before the link failure the traffic is flowing from
Ahmadabad to Mumbai1 directly via path 172.16.1.6  172.16.100.3.

Figure 18 Traffic routed by OSPF after link failure
The figure above shows that after the mux failure at Mumbai 1 the serial links
from Ahmadabad → NewDelhi1 failed, So the traffic changed its path via
NewDelhi1  NewDelhi2 (172.16.1.2)  Mumbai2 (172.16.1.38) 
Mumbai1(172.16.1.26) because of OSPF. (Refer to Network Design). Now the
new route caused congestion on the NewDelhi2  Mumbai2 link as it already
had its own traffic and the traffic from NewDelhi1 as well on the link.
Figure19 Traffic congestion on NewDelhi2  Mumbai2 link
As mentioned above this link got congested and so the packets started
dropping.
4.1.1 Solution to the problem
Due to the network congestion on the NewDelhi2Mumbai2 link the traffic
packets started dropping. Customers started facing jitter and latency on their
applications. As per SLA the client drifted on to the backup link which network
company had to pay. After considering availability on alternative links and

requirement network engineers suggested a solution as Traffic Engineering.
Mentioned below are the results of implementing TE on the network.
Figure 19
The figure above explains that the data has been rerouted explicitly via tunnel
made on Ahmadabad. This was done in order to overcome the congestion on
the NewDelhi2  Mumbai2 link. Traffic Engineering was implemented on
Ahmadabad to reroute the traffic via NewDelhi2  NewDelhi1  Hyderabad
 Mumbai2  Mumbai1 (Please refer to Network Diagram) as this link was
not busy. And the traffic from New Delhi locations followed the same path.
Thus the traffic load was evenly balanced.
4.3 Possible Solutions with a reference to objectives
Now after we have practically implemented MPLS TE on the sample network.
It is clearly visible that MPLS TE stands out to be the choicest solution to the
problems being faced by the current Service Providers. MPLS TE is one of
the most popular and recommended solution to the above mentioned
problems (Ref problem definition section 1.1). TE uses RSVP which solves
the problem of availability as it reserves the bandwidth resources for the traffic
to flow, thus the resources are always available. TE uses the redundant paths
for the traffic flow, thus ensuring the path availability at all times. With the help
of MPLS technology routers now only have to store LFB and there is no need
of address forwarding table which reduces their CPU cycles which in return

increases their availability. With MP-iBGP (Multi Protocol Interior Border
Gateway Protocol) VRF (Virtual Route Forwarding) can be build on the CE
(Customer Edge) which helps customers to use the same IP address on their
ends, thus it saves the IP addresses. Therefore MPLS networks solve the
problem of IP address shortage and are easily scalable. MPLS core networks
are highly secure and reliable as all the MPLS core information is hidden from
end users to meet SLAs. As the data travels across point to point tunnels,
delivery is guaranteed. MPLS TE also provides protection against link/node
failures with the help of Fast Reroute which further adds to the reliability of the
network. Also with MPLS the LSP repair is very fast thus minimising network
traffic and increasing network reliability.
In the thesis we have done complete Investigation and research in TE using
literature review. Limitations of traditional IP networks led to the evolution of
such a technology. This report theoretically and practically proves MPLS TE
advantages over existing technologies. We conducted a real ISP network
simulation to compare MPLS against existing technologies. A complete
analysis of the network model was conducted and the following results have
been produced.
Conclusion
This report concludes the following results. The experiment proves that MPLS
along with the TE is more reliable and secure for the SP. With the help of
MPLS TE, SP can provide cost effective solutions to the clients. At the same
time they can increase their profits by using the existing infrastructure in place
only by manipulating the traffic. As the network expansion is very expensive
so in order to use the existing setup and to meet the customer standards of
satisfaction, SP use MPLS TE as a definite solution.
• This research work explains the best way to implement MPLS TE
keeping in mind the limitations and requirements.

• MPLS TE serves as temporary/permanent congestion avoidance tool
and can provide full scalability and reliability for real time data traffic.
• ISP Core network has been implemented which proves that MPLS is
used for providing virtual lease lines for an efficient and effective data
communication.
• Services provided by MPLS such as MPLS TE and MPLS VPN are a
single choice for ISP to achieve high standards of SLAs.
• MPLS TE is a statmux technology which is better than existing TDM
and FDM technologies. It covers the shortcomings of existing
technologies and adds new feature to ISP networks.
• It has been shown that TE and MPLS are orthogonal technologies but
when combined together works out best for ISP core networks.
Limitations of the research work
While implementing the technology we came across few limitations and
problems. The main limitation was the need of powerful processing devices
due to which the model was implemented on Dynagen. The main idea behind
the project was to gain in depth knowledge of MPLS TE and other
technologies and to gain hands on experience on them. The advanced
features of fast reroute, inter area tunnelling mesh tunnelling could not be
implemented due to resource constraints. To run a real ISP network virtually
was not an easy task. A high end computer with latest core 2 duo processor,
4 GB Ram was used to run 9 routers on a virtual platform. IOS images are not
accessible for general purposes, thus IOS image version 12.4 was used on
company premises on their real time network.
Future Recommendations

In the thesis the advanced features of mesh tunnelling, fast reroute, sonnet
links, GMPLS could not be done as these features required extra bandwidth
and higher resources. For future it is recommended to use these features.
Also MPLS should be implanted and tested with the IP version 6 for scalability
reasons. Only the Tactical design of TE has been used in the experiment but
for future dynamic TE can be used. MPLS TE has a wide variety of services
and application so depending on the requirements these applications can be
used to increase efficiency and save cost.

Bibliography
• Tulip company profile. Available from:
http://www.tulip.net/AboutUs/Companyprofile.htm. [Accessed: 15 /
07/09].
• Tulip clients. Available from:
http://www.tulip.net/Clients/OurClients.htm. [Accessed: 15/07/09].
• Research Methodology. Available from:
http://www.scribd.com/doc/939968/Research-Methodology-Part-1-
Introduction-to-Research-Research-Methodology. [Accessed:
17/07/09].
• RFC1918: Address allocation for private internets. Available from:
http://www.faqs.org/rfcs/rfc1918.html. [Accessed: 17/07/09].
• Core Network. Available from: http://www.linktionary.com/c/core.html.
[Accessed: 18/07/09].
• Cisco 7000 series router. Available from:
http://newsroom.cisco.com/dlls/2004/hd_050404.html. [Accessed:
20/07/09].
• ATM Switching. Available from:
http://www.cisco.com/en/US/docs/internetworking/technology/handboo
k/atm.html. [Accessed: 21/07/09].
• Cisco Frame Relay. Available from:
http://www.cisco.com/en/US/docs/internetworking/technology/handboo
k/Frame-Relay.html#wp1020734 . [Accessed: 22/07/09].
• MPLS Overview. Available from:
http://www.juniper.net/techpubs/software/junos/junos53/swconfig53-
mpls-apps/html/mpls-overview.html. [Accessed: 22/07/09].

• Traffic Engineering. Available from:
http://www.mplstutorial.com/mpls-traffic-engineering-te-introduction-
and-objectives.[Accessed: 23/07/09].
• Multiprotocol Label Switching (MPLS). Available from:
http://www.cisco.com/en/US/products/ps6557/products_ios_technology
home.html [Accessed: 23/07/09]
• An Introduction to MPLS from:
http://www.convergedigest.com/Bandwidth/archive/010910TUTORIAL-
rgallaher1.htm [Accessed: 23/07/09]

Router Configurations
Delhi 1
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Delhi1

!
boot-start-marker
boot-end-marker
!
enable password cisco
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
!
!
mpls traffic-eng tunnels
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!

!
!
!
interface Loopback0
ip address 172.16.100.1 255.255.255.255
ip ospf 1 area 0
!
interface Serial0/0
ip address 172.16.1.10 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls label protocol ldp
mpls ip
serial restart-delay 0
ip rsvp bandwidth 200 200
!
interface Serial0/1
ip address 172.16.1.30 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/2
ip address 172.16.1.33 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip

!
interface Serial0/3
ip address 172.16.1.42 255.255.255.252
ip ospf 1 area 0
mpls ip
!
!
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
router-id 172.16.100.1
log-adjacency-changes
!
ip http server
no ip http secure-server
!
!
!
!
!
mpls ldp router-id Loopback0 force
!
control-plane
!
!
!
!
!
!
!

!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
end
Delhi 2
!
version 12.4
!
hostname delhi2
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$qNJk$HN7mwD3RnxWfCHCSmG/QG1
!
no aaa new-model
memory-size iomem 5
!
!

ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 172.16.100.2 255.255.255.255
ip ospf 1 area 0
!
interface Serial0/0
ip address 172.16.1.37 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0

mpls ip
no fair-queue
!
interface Serial0/1
ip address 172.16.1.2 255.255.255.252
ip ospf cost 60
ip ospf 1 area 0
mpls ip
!
interface Serial0/2
ip address 172.16.1.34 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip
!
interface Serial0/3
no ip address
!
!
router ospf 1

router-id 172.16.100.2
!
ip http server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
End

Ahmadabad
version 12.4
!
hostname ahmd
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
!
!
mpls traffic-eng auto-bw timers
!
!
!
!
!
!
!

!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 172.16.100.7 255.255.255.255
ip ospf 1 area 0
!
interface Tunnel1
no ip address
!
interface Tunnel10
ip unnumbered Loopback0
tunnel destination 172.16.100.4
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth 100
tunnel mpls traffic-eng path-option 1 explicit name TE
tunnel mpls traffic-eng path-option 2 dynamic
tunnel mpls traffic-eng load-share 20
no routing dynamic
!

interface Tunnel20
shutdown
no routing dynamic
!
interface Tunnel30
shutdown
tunnel mpls traffic-eng path-option 1 explicit name MUM1
no routing dynamic
!
interface Tunnel50
description Load Sharing
tunnel mpls traffic-eng path-option 1 explicit name LOADSHARE
tunnel mpls traffic-eng load-share 10
no routing dynamic
!
interface Tunnel60
description Load Balancing To Mumbai 1

shutdown
tunnel mpls traffic-eng path-option 1 explicit name LOADSHARE_ND1
no routing dynamic
!
interface Serial0/0
ip address 172.16.1.5 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
no fair-queue
ip rsvp resource-provider none
!
interface Serial0/1
ip address 172.16.1.1 255.255.255.252
ip ospf cost 60
ip ospf 1 area 0
mpls ip
!
interface Serial0/2
no ip address

!
interface Serial0/3
no ip address
!
!
router ospf 1
router-id 172.16.100.7
!
ip http server
!
!
!
ip explicit-path name TE enable
next-address 172.16.1.2
!
ip explicit-path name TE_PATH enable
!
ip explicit-path name TE_NEW enable

!
ip explicit-path name DEL1 enable
!
ip explicit-path name HYD enable
!
ip explicit-path name MUM1 enable
!
ip explicit-path name LOADSHARE enable
exclude-address 172.16.1.6
exclude-address 172.16.1.25
!
ip explicit-path name LOADSHARE_ND1 enable
!
!

!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
password cisco
no login
!
!
end
Hyderabad
version 12.4

!
hostname hyd
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!

!
!
!
interface Loopback0
ip address 172.16.100.6 255.255.255.255
ip ospf 1 area 0
!
interface Tunnel30
shutdown
tunnel mpls traffic-eng path-option 1 explicit name AHM
no routing dynamic
!
interface Serial0/0
ip address 172.16.1.9 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
no fair-queue
!
interface Serial0/1
ip address 172.16.1.13 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip

!
interface Serial0/2
ip address 172.16.1.17 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/3
no ip address
!
!
router ospf 1
router-id 172.16.100.6
!
ip http server
!
!
!
ip explicit-path name AHM enable
!
!

!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
End
Mumbai 1
!
version 12.4

!
hostname mum1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!

!
!
!
interface Loopback0
ip address 172.16.100.3 255.255.255.255
ip ospf 1 area 0
!
interface Serial0/0
ip address 172.16.1.6 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
no fair-queue
ip rsvp resource-provider none
!
interface Serial0/1
ip address 172.16.1.29 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/2
ip address 172.16.1.26 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip

no fair-queue
!
interface Serial0/3
ip address 172.16.1.45 255.255.255.252
ip ospf 1 area 0
mpls ip
!
!
router ospf 1
router-id 172.16.100.3
!
ip http server
!
!
!
!
!
!
control-plane
!
!
!
!

!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
End
Mumbai 2
version 12.4
!
hostname mum2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model

memory-size iomem 5
!
!
ip cef
no ip domain lookup
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 172.16.100.4 255.255.255.255
ip ospf 1 area 0
!

interface Tunnel10
tunnel mpls traffic-eng path-option 1 explicit name TE
no routing dynamic
!
interface Tunnel20
shutdown
no routing dynamic
!
interface Tunnel30
shutdown
tunnel mpls traffic-eng path-option 1 explicit name MUM1
no routing dynamic
!
interface Tunnel50
description Load Sharing

tunnel mpls traffic-eng path-option 1 explicit name LOADSHARE
no routing dynamic
!
interface Serial0/0
ip address 172.16.1.38 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/1
ip address 172.16.1.14 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/2
ip address 172.16.1.25 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip
no fair-queue

!
interface Serial0/3
ip address 172.16.1.22 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip
!
!
router ospf 1
router-id 172.16.100.4
!
ip http server
!
!
!
ip explicit-path name TE enable
!
ip explicit-path name MUM1 enable
!
ip explicit-path name LOADSHARE enable

!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
End
Mumbai 3
version 12.4

!
hostname mum3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!

!
!
!
!
interface Loopback0
ip address 172.16.100.5 255.255.255.255
ip ospf 1 area 0
!
interface Serial0/0
no ip address
no fair-queue
!
interface Serial0/1
no ip address
!
interface Serial0/2
ip address 172.16.1.18 255.255.255.252
ip ospf cost 50
ip ospf 1 area 0
mpls ip
!
interface Serial0/3
ip address 172.16.1.21 255.255.255.252
ip ospf cost 1
ip ospf 1 area 0
mpls ip
!

!
router ospf 1
router-id 172.16.100.5
!
ip http server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
!
End

Chandigarh
version 12.4
!
hostname Chd
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
!
!
ip vrf A
rd 65500:1
route-target export 65500:1
route-target import 65500:1
!
ip vrf B
rd 65500:2
route-target export 65500:2
route-target import 65500:2

!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 172.16.100.8 255.255.255.255
ip ospf 1 area 1
!
interface Loopback10
ip vrf forwarding A
ip address 192.168.1.2 255.255.255.255
!
interface Loopback20
ip vrf forwarding B

ip address 192.168.1.2 255.255.255.255
!
interface Serial0/0
no ip address
shutdown
no fair-queue
!
interface Serial0/1
no ip address
shutdown
!
interface Serial0/2
no ip address
shutdown
!
interface Serial0/3
ip address 172.16.1.41 255.255.255.252
ip ospf 1 area 0
mpls ip
!
!
router ospf 1
router-id 172.16.100.8
!
router bgp 65500
bgp router-id 172.16.100.8
bgp log-neighbor-changes

neighbor 172.16.100.9 remote-as 65500
neighbor 172.16.100.9 update-source Loopback0
!
address-family ipv4
neighbor 172.16.100.9 activate
no auto-summary
no synchronization
exit-address-family
!
address-family vpnv4
neighbor 172.16.100.9 activate
neighbor 172.16.100.9 send-community both
exit-address-family
!
address-family ipv4 vrf B
redistribute connected
no synchronization
exit-address-family
!
address-family ipv4 vrf A
redistribute connected
no synchronization
exit-address-family
!
ip http server
!
!
!
!
!
!

control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
End
Pune
version 12.4
!
hostname Pune
!
boot-start-marker
boot-end-marker

!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 172.16.100.9 255.255.255.255

ip ospf 1 area 2
!
interface Serial0/0
no ip address
shutdown
!
interface Serial0/1
no ip address
shutdown
!
interface Serial0/2
no ip address
shutdown
!
interface Serial0/3
ip address 172.16.1.46 255.255.255.252
ip ospf 1 area 0
mpls ip
!
!
router ospf 1
!
ip http server
!
!
!

!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

dissertation

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dissertation