SlideShare a Scribd company logo
Module 11: Network Design
Instructor Materials
Enterprise Networking, Security, and Automation v7.0
(ENSA)
Module 11: Network
Design
Enterprise Networking, Security, and Automation v7.0
(ENSA)
10
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Module Objectives
Module Title: Network Design
Module Objective: Explain the characteristics of scalable network architectures.
Topic Title Topic Objective
Hierarchical Networks
Explain how data, voice, and video are converged
in a switched network.
Scalable Networks
Explain considerations for designing a scalable
network.
Switch Hardware
Explain how switch hardware features support
network requirements.
Router Hardware
Describe the types of routers available for small to-
medium-sized business networks.
11
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
11.1 Hierarchical Networks
12
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Video - Three-Layer Network Design
This video will demonstrate a three-layer model in network design.
Core layer
Distribution layer
Access layer
13
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
The Need to Scale the Network
Organizations increasingly rely on their network infrastructure to provide mission-critical
services.
Evolving organizations require networks that can scale and support:
• Converged network traffic
• Critical applications
• Diverse business needs
• Centralized administrative control
Campus network designs include small networks that use a single LAN switch, up to very
large networks with thousands of connections.
14
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Borderless Switched Networks
The Cisco Borderless Network is a network architecture that can connect anyone,
anywhere, anytime, on any device; securely, reliably, and seamlessly.
• It provides the framework to
unify wired and wireless
access, built on a
hierarchical infrastructure of
hardware that is scalable
and resilient.
• Borderless switched
networks are hierarchical,
modular, resilient, and
flexible.
15
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Hierarchy in the Borderless Switched Network
Hierarchical networks use a tiered design of access, distribution, and core layers with
each layer performing a well-defined role in the campus network.
There are
two time-
tested
and
proven
hierarchic
al design
framewor
ks for
campus
networks.
Three-tier layer Two-tier layer
16
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Access, Distribution, and Core Layer Functions
Access Layer
• The access layer provide network access to the user.
• Access layer switches connect to distribution layer switches.
Distribution Layer
• The distribution layer implements routing, quality of service, and security.
• It aggregates large-scale wiring closet networks and limits Layer 2 broadcast domains.
• Distribution layer switches connect to access layer and core layer switches.
Core Layer
• The core layer is the network backbone and connects several layers of the network.
• The core layer provides fault isolation and high-speed backbone connectivity.
17
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Three-Tier and Two-Tier Examples
Three-tier Campus Network
• Used by organizations requiring access, distribution, and core
layers.
• The recommendation is to build an extended-star physical
network topology from a centralized building location to all other
buildings on the same campus.
Two-tier Campus Network
• Used when separate distribution and core layers is not required.
• Useful for smaller campus locations, or in campus sites consisting of
a single building.
• Also known as the collapsed core network design.
18
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Hierarchical Networks
Role of Switched Networks
• Networks have fundamentally changed
from a flat network of hubs to switched
LANs in a hierarchical network.
• A switched LAN allows:
• additional flexibility,
• traffic management,
• quality of service,
• security.
• A switched LAN may also support
wireless networking and other
technologies such as IP telephone and
mobility services.
19
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
11.2 Scalable Networks
20
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Design for Scalability
Scalability is the term for a network that can grow without losing availability and reliability.
Network designers must develop strategies to enable the network to be available and to
scale effectively and easily.
This is accomplished using:
• Redundancy
• Multiple Links
• Scalable Routing protocol
• Wireless Connectivity
21
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Plan for Redundancy
Redundancy can prevent disruption of network services by minimizing the possibility of a
single point of failure by:
• Installing duplicate equipment
• Providing failover services for critical devices
Redundant paths offer alternate physical paths
for data to traverse the network supporting high
availability (HA).
• However, redundant paths in an Ethernet
network may cause logical Layer 2 loops.
• Therefore, Spanning Tree Protocol (STP) is
required.
22
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Reduce Failure Domain Size
A well-designed network controls traffic and limits the size of failure domains (i.e., the area
of a network that is impacted when the network experiences problems).
• In the hierarchical design model, failure domains are terminated at the distribution layer.
• Every router functions as a gateway for a limited number of access layer users.
Routers, or multilayer switches, are usually deployed in pairs in a configuration referred to
as a building, or departmental, switch block.
• Each switch block acts independently of the others.
• As a result, the failure of a single device does not cause the network to go down.
23
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Increase Bandwidth
Link aggregation (e.g., EtherChannel) allows an administrator to increase the amount of
bandwidth between devices by creating one logical link made up of several physical links.
• EtherChannel combines existing switch ports
into one logical link using a Port Channel
interface.
• Most configuration tasks are done on the Port
Channel interface (instead of on each
individual port) to ensure configuration
consistency on the links.
• EtherChannel can load balance between
links.
24
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Expand the Access Layer
An increasingly popular option for extending access layer connectivity is through wireless.
• Wireless LANs (WLANs) provides increased flexibility, reduced costs, and the ability to grow and
adapt to changing network and business requirements.
• To communicate wirelessly, end devices require a
wireless NIC to connect to a wireless router or a
wireless access point (AP).
Considerations when implementing a wireless
network include:
• Types of wireless devices connecting to the WLAN
• Wireless coverage requirements
• Interference considerations
• Security considerations
25
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Scalable Networks
Tune Routing Protocols
Advanced routing protocols, such as Open Shortest Path First (OSPF) are used in large
networks.
• OSPF is a link-state routing protocol
that uses areas to support a
hierarchical networks.
• OSPF routers establish and
maintain neighbor adjacencies with
other connected OSPF routers.
• OSPF routers synchronize their link-
state database.
• When a network change occurs,
link-state updates are sent,
informing other OSPF routers of the
change and establishing a new best
path, if one is available.
26
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
11.3 Switch Hardware
27
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Switch Platforms
• There is a variety of switch platforms, form factors, and other features that must be
considered before choosing a switch.
• When designing a network, it is important to select the proper hardware to meet
current network requirements, as well as to allow for network growth.
• Within an enterprise network, both switches and routers play a critical role in
network communication.
Campus LAN Switches, such as the Cisco
3850 series shown here, support high
concentrations of user connections with
speed and security appropriate for the
enterprise network.
28
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Switch Platforms (Cont.)
Cisco Meraki cloud-managed access
switches enable virtual stacking of switches.
They monitor and configure thousands of
switch ports over the web, without the
intervention of onsite IT staff.
The Cisco Nexus platform
promotes infrastructure
scalability, operational
continuity, and transport
flexibility in the data center.
29
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Switch Platforms (Cont.)
Cisco Nexus virtual networking
switch platforms provide secure
multi-tenant services by adding
virtualization intelligence
technology to the data center
network.
Service provider Ethernet access switches
feature application intelligence, unified
services, virtualization, integrated security,
and simplified management.
30
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Switch Form Factors
When selecting switches, network administrators must determine the switch form factors.
This includes fixed configuration, modular configuration, stackable, or non-stackable.
Features and options on fixed configuration switches
are limited to those that originally come with the switch.
The chassis on modular switches accept field-
replaceable line cards.
31
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Switch Form Factors (Cont.)
Special cables are used to connect stackable switches that
allow them to effectively operate as one large switch.
The thickness of the switch, which is expressed in the number of rack units, is also
important for switches that are mounted in a rack. For example, the fixed configuration
switches shown in the figure are all one rack units (1U) or 1.75 inches (44.45 mm) in height.
32
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Port Density
The port density of a switch refers to the number of ports available on a single switch.
Fixed configuration switches support a
variety of port density configurations. The
Cisco Catalyst 3850 come in 12, 24, 48
port configurations. Modular switches can support very high
port densities through the addition of
multiple switchport line cards. The
modular Catalyst 9400 switch supports
384 switchport interfaces.
33
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Forwarding Rates
Forwarding rates define the processing capabilities of a switch by rating how much data
the switch can process per second.
• Switch product lines are classified by forwarding rates.
• Entry-level switches have lower forwarding rates than enterprise-level switches.
If switch forwarding rate is too low, it cannot accommodate full wire-speed communication
across all of its switch ports.
• Wire speed is the data rate that each Ethernet port on the switch is capable of
attaining.
• Data rates can be 100 Mbps, 1 Gbps, 10 Gbps, or 100 Gbps.
• Access layer switches typically do not need to operate at full wire speed, because they
are physically limited by their uplinks to the distribution layer.
34
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Power over Ethernet
Power over Ethernet (PoE) allows the switch to deliver power to a device (e.g., IP phone,
AP, camera) over the existing Ethernet cabling.
A network administrator should ensure that the PoE features are actually required for a
given installation, because switches that support PoE are expensive.
35
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Multilayer Switching
Multilayer switches are typically deployed in the core and distribution layers of an
organization's switched network.
• They support some routing protocols and forward IP packets at a rate close to that of
Layer 2 forwarding.
• Multilayer switches often support specialized hardware, such as application-specific
integrated circuits (ASICs).
• ASICs along with dedicated software data structures can streamline the forwarding of
IP packets independent of the CPU.
36
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Switch Hardware
Business Considerations for Switch Selection
Consideration Description
Cost
The cost of a switch will depend on the number and speed of the interfaces, supported features,
and expansion capability.
Port density Network switches must support the appropriate number of devices on the network.
Power
It is now common to power access points, IP phones, and compact switches user Power over
Ethernet (PoE).
In addition to PoE considerations, some chassis-based switches support redundant power
supplies.
Reliability The switch should provide continuous access to the network.
Port speed The speed of the network connection is of primary concern to end users.
Frame buffers
The ability of the switch to store frames is important in a network where there may be congested
ports to servers or other areas of the network.
Scalability
The number of users on a network typically grows over time; therefore, the switch should
provide the opportunity for growth.
37
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
11.4 Router Hardware
38
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Router Requirements
Routers use the network portion (prefix) of the destination IP address to route packets to
the proper destination.
• They select an alternate path if a link goes down.
• All hosts on a network specify the IP address of the local router interface as their
default gateway.
Routers also serve other beneficial functions as follows:
• They provide broadcast containment by limiting broadcasts to the local network.
• They interconnect geographically separated locations.
• The group users logically by application or department within a company, who have
command needs or require access to the same resources.
• They provide enhanced security by filtering unwanted traffic through access control
lists.
39
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Cisco Routers
Branch routers, shown in the figure, optimize branch services on a single platform while
delivering an optimal application experience across branch and WAN infrastructures.
Shown are the Cisco Integrated Services Router (ISR) 4000 Series Routers.
40
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Cisco Routers (Cont.)
Network edge routers, shown in the figure, enable the network edge to deliver high-
performance, highly secure, and reliable services that unite campus, data center, and
branch networks. Shown are the Cisco Aggregation Services Routers (ASR) 9000
Series Routers.
41
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Cisco Routers (Cont.)
Service provider routers, shown in the figure, deliver end-to-end scalable solutions and
subscriber-aware services. Shown are the Cisco Network Convergence System (NCS)
6000 Series Routers.
42
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Cisco Routers (Cont.)
Industrial routers, such as the ones shown in the figure, are designed to provide
enterprise-class features in rugged and harsh environments. Shown are the Cisco 1100
Series Industrial Integrated Services Routers.
43
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Router Form Factors
Cisco 900 Series: This is a small branch office router. It combines WAN, switching,
security, and advanced connectivity options in a compact, fanless platform for small and
medium-sized businesses.
44
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Router Form Factors
Cisco ASR 9000 and 1000 Series Aggregation Services Routers: These routers
provide density and resiliency with programmability, for a scalable network edge.
45
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Router Form Factors
Cisco Network Convergence System 5500
Series Routers: These routers are designed to
efficiently scale between large data centers and
large enterprise networks, web, and service
provider WAN and aggregation networks.
46
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Router Hardware
Router Form Factors
Cisco 800 Industrial Integrated Services Router: This router is compact and designed
for harsh environments.
47
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
11.5 Module Practice and Quiz
48
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Module Practice and Quiz
Packet Tracer - Compare Layer 2 and Layer 3 Devices
In this Packet Tracer activity, you will use various commands to examine three different
switching topologies and compare the similarities and differences between the 2960 and
3650 switches.
You will also compare the routing table of a 4321 router with that of a 3650 switch.
49
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Module Practice and Quiz
What did I learn in this module?
• The Cisco Borderless Network provides the framework to unify wired and wireless access,
and is built on a hierarchical infrastructure of hardware that is scalable and resilient.
• Two proven hierarchical design frameworks for campus networks are the three-tier layer and
the two-tier layer models.
• The three critical layers within these tiered designs are the access, distribution, and core
layers.
• Implement redundant links between critical devices and between access layer and core layer
devices.
• Implement multiple links between equipment, with either link aggregation (EtherChannel) or
equal cost load balancing, to increase bandwidth.
• Use a scalable routing protocol and implementing features to minimize the routing table size.
• Implement wireless connectivity to allow for mobility and expansion.
50
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
Module Practice and Quiz
What did I learn in this module? (Cont.)
• There are campus LAN, cloud-managed, data center, service provider, and virtual networking
witches.
• Form factors for switches include fixed configuration, modular configuration, and stack
• Routers use the network portion (prefix) of the destination IP address to route packets to the
proper destination.
• Routers select an alternate path if a link or path goes down.
• Cisco has several categories of routers including branch, network edge, service provider and
industrial.
ENSA_Module_11 - Network Design.pdf.mtzm

More Related Content

PPTX
ScaNv6_instructorPPT_Chapter1 LAN Design
PPTX
CCNA_RSE_Chp4 and their working principles.pptx
PPTX
CCNA_RSE_Chp4.pptx
PPTX
CCNA_RSE_Chp4 - Switched Networks for CCNA
PPTX
NDIC-Module1 : module jaringan komputer.pptx
PPT
E s switch_v6_ch01
PPTX
Apresentação ccna en_SWITCH_v6_Ch01.pptx
PPTX
IS404 Data Communication III.pptx
ScaNv6_instructorPPT_Chapter1 LAN Design
CCNA_RSE_Chp4 and their working principles.pptx
CCNA_RSE_Chp4.pptx
CCNA_RSE_Chp4 - Switched Networks for CCNA
NDIC-Module1 : module jaringan komputer.pptx
E s switch_v6_ch01
Apresentação ccna en_SWITCH_v6_Ch01.pptx
IS404 Data Communication III.pptx

Similar to ENSA_Module_11 - Network Design.pdf.mtzm (20)

PPTX
CCNP Switching Chapter 2
PPTX
CCNP v6 Route: Implementing IP Routing Chapter1
PPT
01 route routing services
PDF
SMB_University_120307_Networking_Fundamentals.pdf
PDF
SMB_University_120307_Networking_Fundamentals.pdf
DOC
Ccna exploration 3 lan switching and wireless
PPTX
Vcs standard ccna 2 ch-1.1
PPTX
Lan switching & wirless lecture # 1
PPTX
CCNA2 Verson6 Chapter4
PDF
Examen1ccna3v5.0
PPT
Dcna technology update
PPTX
10. Network Design10. Network Design.pptx
PDF
CCNAv5 - S2: Chapter1 Introsuction to switched networks
PPTX
rsinstructorpptchapter1final-141024021337-conversion-gate01
PPTX
KPUCC-Rs instructor ppt_chapter1_final
PPTX
SDN 101: Software Defined Networking Course - Sameh Zaghloul/IBM - 2014
PPTX
CCNA 2 Routing and Switching v5.0 Chapter 1
PPTX
Chapter 12 : Introduction to switched networks
PDF
introduction to switched networks - JARINGAN KOMPUTER
CCNP Switching Chapter 2
CCNP v6 Route: Implementing IP Routing Chapter1
01 route routing services
SMB_University_120307_Networking_Fundamentals.pdf
SMB_University_120307_Networking_Fundamentals.pdf
Ccna exploration 3 lan switching and wireless
Vcs standard ccna 2 ch-1.1
Lan switching & wirless lecture # 1
CCNA2 Verson6 Chapter4
Examen1ccna3v5.0
Dcna technology update
10. Network Design10. Network Design.pptx
CCNAv5 - S2: Chapter1 Introsuction to switched networks
rsinstructorpptchapter1final-141024021337-conversion-gate01
KPUCC-Rs instructor ppt_chapter1_final
SDN 101: Software Defined Networking Course - Sameh Zaghloul/IBM - 2014
CCNA 2 Routing and Switching v5.0 Chapter 1
Chapter 12 : Introduction to switched networks
introduction to switched networks - JARINGAN KOMPUTER
Ad

Recently uploaded (20)

PDF
Phone away, tabs closed: No multitasking
PDF
Emailing DDDX-MBCaEiB.pdf DDD_Europe_2022_Intro_to_Context_Mapping_pdf-165590...
PPT
Machine printing techniques and plangi dyeing
PPTX
CLASSIFICATION OF YARN- process, explanation
PPT
UNIT I- Yarn, types, explanation, process
PDF
Urban Design Final Project-Site Analysis
PPTX
YV PROFILE PROJECTS PROFILE PRES. DESIGN
PPTX
BSCS lesson 3.pptxnbbjbb mnbkjbkbbkbbkjb
PPTX
DOC-20250430-WA0014._20250714_235747_0000.pptx
PDF
YOW2022-BNE-MinimalViableArchitecture.pdf
PDF
Facade & Landscape Lighting Techniques and Trends.pptx.pdf
PPTX
AC-Unit1.pptx CRYPTOGRAPHIC NNNNFOR ALL
PPTX
NEW EIA PART B - Group 5 (Section 50).pptx
PDF
Interior Structure and Construction A1 NGYANQI
PDF
BRANDBOOK-Presidential Award Scheme-Kenya-2023
PPT
robotS AND ROBOTICSOF HUMANS AND MACHINES
PDF
Design Thinking - Module 1 - Introduction To Design Thinking - Dr. Rohan Dasg...
PDF
Introduction-to-World-Schools-format-guide.pdf
PPTX
LITERATURE CASE STUDY DESIGN SEMESTER 5.pptx
PPTX
rapid fire quiz in your house is your india.pptx
Phone away, tabs closed: No multitasking
Emailing DDDX-MBCaEiB.pdf DDD_Europe_2022_Intro_to_Context_Mapping_pdf-165590...
Machine printing techniques and plangi dyeing
CLASSIFICATION OF YARN- process, explanation
UNIT I- Yarn, types, explanation, process
Urban Design Final Project-Site Analysis
YV PROFILE PROJECTS PROFILE PRES. DESIGN
BSCS lesson 3.pptxnbbjbb mnbkjbkbbkbbkjb
DOC-20250430-WA0014._20250714_235747_0000.pptx
YOW2022-BNE-MinimalViableArchitecture.pdf
Facade & Landscape Lighting Techniques and Trends.pptx.pdf
AC-Unit1.pptx CRYPTOGRAPHIC NNNNFOR ALL
NEW EIA PART B - Group 5 (Section 50).pptx
Interior Structure and Construction A1 NGYANQI
BRANDBOOK-Presidential Award Scheme-Kenya-2023
robotS AND ROBOTICSOF HUMANS AND MACHINES
Design Thinking - Module 1 - Introduction To Design Thinking - Dr. Rohan Dasg...
Introduction-to-World-Schools-format-guide.pdf
LITERATURE CASE STUDY DESIGN SEMESTER 5.pptx
rapid fire quiz in your house is your india.pptx
Ad

ENSA_Module_11 - Network Design.pdf.mtzm

  • 1. Module 11: Network Design Instructor Materials Enterprise Networking, Security, and Automation v7.0 (ENSA)
  • 2. Module 11: Network Design Enterprise Networking, Security, and Automation v7.0 (ENSA)
  • 3. 10 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Objectives Module Title: Network Design Module Objective: Explain the characteristics of scalable network architectures. Topic Title Topic Objective Hierarchical Networks Explain how data, voice, and video are converged in a switched network. Scalable Networks Explain considerations for designing a scalable network. Switch Hardware Explain how switch hardware features support network requirements. Router Hardware Describe the types of routers available for small to- medium-sized business networks.
  • 4. 11 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11.1 Hierarchical Networks
  • 5. 12 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Video - Three-Layer Network Design This video will demonstrate a three-layer model in network design. Core layer Distribution layer Access layer
  • 6. 13 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks The Need to Scale the Network Organizations increasingly rely on their network infrastructure to provide mission-critical services. Evolving organizations require networks that can scale and support: • Converged network traffic • Critical applications • Diverse business needs • Centralized administrative control Campus network designs include small networks that use a single LAN switch, up to very large networks with thousands of connections.
  • 7. 14 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Borderless Switched Networks The Cisco Borderless Network is a network architecture that can connect anyone, anywhere, anytime, on any device; securely, reliably, and seamlessly. • It provides the framework to unify wired and wireless access, built on a hierarchical infrastructure of hardware that is scalable and resilient. • Borderless switched networks are hierarchical, modular, resilient, and flexible.
  • 8. 15 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Hierarchy in the Borderless Switched Network Hierarchical networks use a tiered design of access, distribution, and core layers with each layer performing a well-defined role in the campus network. There are two time- tested and proven hierarchic al design framewor ks for campus networks. Three-tier layer Two-tier layer
  • 9. 16 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Access, Distribution, and Core Layer Functions Access Layer • The access layer provide network access to the user. • Access layer switches connect to distribution layer switches. Distribution Layer • The distribution layer implements routing, quality of service, and security. • It aggregates large-scale wiring closet networks and limits Layer 2 broadcast domains. • Distribution layer switches connect to access layer and core layer switches. Core Layer • The core layer is the network backbone and connects several layers of the network. • The core layer provides fault isolation and high-speed backbone connectivity.
  • 10. 17 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Three-Tier and Two-Tier Examples Three-tier Campus Network • Used by organizations requiring access, distribution, and core layers. • The recommendation is to build an extended-star physical network topology from a centralized building location to all other buildings on the same campus. Two-tier Campus Network • Used when separate distribution and core layers is not required. • Useful for smaller campus locations, or in campus sites consisting of a single building. • Also known as the collapsed core network design.
  • 11. 18 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Hierarchical Networks Role of Switched Networks • Networks have fundamentally changed from a flat network of hubs to switched LANs in a hierarchical network. • A switched LAN allows: • additional flexibility, • traffic management, • quality of service, • security. • A switched LAN may also support wireless networking and other technologies such as IP telephone and mobility services.
  • 12. 19 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11.2 Scalable Networks
  • 13. 20 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Design for Scalability Scalability is the term for a network that can grow without losing availability and reliability. Network designers must develop strategies to enable the network to be available and to scale effectively and easily. This is accomplished using: • Redundancy • Multiple Links • Scalable Routing protocol • Wireless Connectivity
  • 14. 21 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Plan for Redundancy Redundancy can prevent disruption of network services by minimizing the possibility of a single point of failure by: • Installing duplicate equipment • Providing failover services for critical devices Redundant paths offer alternate physical paths for data to traverse the network supporting high availability (HA). • However, redundant paths in an Ethernet network may cause logical Layer 2 loops. • Therefore, Spanning Tree Protocol (STP) is required.
  • 15. 22 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Reduce Failure Domain Size A well-designed network controls traffic and limits the size of failure domains (i.e., the area of a network that is impacted when the network experiences problems). • In the hierarchical design model, failure domains are terminated at the distribution layer. • Every router functions as a gateway for a limited number of access layer users. Routers, or multilayer switches, are usually deployed in pairs in a configuration referred to as a building, or departmental, switch block. • Each switch block acts independently of the others. • As a result, the failure of a single device does not cause the network to go down.
  • 16. 23 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Increase Bandwidth Link aggregation (e.g., EtherChannel) allows an administrator to increase the amount of bandwidth between devices by creating one logical link made up of several physical links. • EtherChannel combines existing switch ports into one logical link using a Port Channel interface. • Most configuration tasks are done on the Port Channel interface (instead of on each individual port) to ensure configuration consistency on the links. • EtherChannel can load balance between links.
  • 17. 24 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Expand the Access Layer An increasingly popular option for extending access layer connectivity is through wireless. • Wireless LANs (WLANs) provides increased flexibility, reduced costs, and the ability to grow and adapt to changing network and business requirements. • To communicate wirelessly, end devices require a wireless NIC to connect to a wireless router or a wireless access point (AP). Considerations when implementing a wireless network include: • Types of wireless devices connecting to the WLAN • Wireless coverage requirements • Interference considerations • Security considerations
  • 18. 25 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Scalable Networks Tune Routing Protocols Advanced routing protocols, such as Open Shortest Path First (OSPF) are used in large networks. • OSPF is a link-state routing protocol that uses areas to support a hierarchical networks. • OSPF routers establish and maintain neighbor adjacencies with other connected OSPF routers. • OSPF routers synchronize their link- state database. • When a network change occurs, link-state updates are sent, informing other OSPF routers of the change and establishing a new best path, if one is available.
  • 19. 26 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11.3 Switch Hardware
  • 20. 27 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Switch Platforms • There is a variety of switch platforms, form factors, and other features that must be considered before choosing a switch. • When designing a network, it is important to select the proper hardware to meet current network requirements, as well as to allow for network growth. • Within an enterprise network, both switches and routers play a critical role in network communication. Campus LAN Switches, such as the Cisco 3850 series shown here, support high concentrations of user connections with speed and security appropriate for the enterprise network.
  • 21. 28 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Switch Platforms (Cont.) Cisco Meraki cloud-managed access switches enable virtual stacking of switches. They monitor and configure thousands of switch ports over the web, without the intervention of onsite IT staff. The Cisco Nexus platform promotes infrastructure scalability, operational continuity, and transport flexibility in the data center.
  • 22. 29 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Switch Platforms (Cont.) Cisco Nexus virtual networking switch platforms provide secure multi-tenant services by adding virtualization intelligence technology to the data center network. Service provider Ethernet access switches feature application intelligence, unified services, virtualization, integrated security, and simplified management.
  • 23. 30 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Switch Form Factors When selecting switches, network administrators must determine the switch form factors. This includes fixed configuration, modular configuration, stackable, or non-stackable. Features and options on fixed configuration switches are limited to those that originally come with the switch. The chassis on modular switches accept field- replaceable line cards.
  • 24. 31 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Switch Form Factors (Cont.) Special cables are used to connect stackable switches that allow them to effectively operate as one large switch. The thickness of the switch, which is expressed in the number of rack units, is also important for switches that are mounted in a rack. For example, the fixed configuration switches shown in the figure are all one rack units (1U) or 1.75 inches (44.45 mm) in height.
  • 25. 32 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Port Density The port density of a switch refers to the number of ports available on a single switch. Fixed configuration switches support a variety of port density configurations. The Cisco Catalyst 3850 come in 12, 24, 48 port configurations. Modular switches can support very high port densities through the addition of multiple switchport line cards. The modular Catalyst 9400 switch supports 384 switchport interfaces.
  • 26. 33 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Forwarding Rates Forwarding rates define the processing capabilities of a switch by rating how much data the switch can process per second. • Switch product lines are classified by forwarding rates. • Entry-level switches have lower forwarding rates than enterprise-level switches. If switch forwarding rate is too low, it cannot accommodate full wire-speed communication across all of its switch ports. • Wire speed is the data rate that each Ethernet port on the switch is capable of attaining. • Data rates can be 100 Mbps, 1 Gbps, 10 Gbps, or 100 Gbps. • Access layer switches typically do not need to operate at full wire speed, because they are physically limited by their uplinks to the distribution layer.
  • 27. 34 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Power over Ethernet Power over Ethernet (PoE) allows the switch to deliver power to a device (e.g., IP phone, AP, camera) over the existing Ethernet cabling. A network administrator should ensure that the PoE features are actually required for a given installation, because switches that support PoE are expensive.
  • 28. 35 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Multilayer Switching Multilayer switches are typically deployed in the core and distribution layers of an organization's switched network. • They support some routing protocols and forward IP packets at a rate close to that of Layer 2 forwarding. • Multilayer switches often support specialized hardware, such as application-specific integrated circuits (ASICs). • ASICs along with dedicated software data structures can streamline the forwarding of IP packets independent of the CPU.
  • 29. 36 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Switch Hardware Business Considerations for Switch Selection Consideration Description Cost The cost of a switch will depend on the number and speed of the interfaces, supported features, and expansion capability. Port density Network switches must support the appropriate number of devices on the network. Power It is now common to power access points, IP phones, and compact switches user Power over Ethernet (PoE). In addition to PoE considerations, some chassis-based switches support redundant power supplies. Reliability The switch should provide continuous access to the network. Port speed The speed of the network connection is of primary concern to end users. Frame buffers The ability of the switch to store frames is important in a network where there may be congested ports to servers or other areas of the network. Scalability The number of users on a network typically grows over time; therefore, the switch should provide the opportunity for growth.
  • 30. 37 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11.4 Router Hardware
  • 31. 38 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Router Requirements Routers use the network portion (prefix) of the destination IP address to route packets to the proper destination. • They select an alternate path if a link goes down. • All hosts on a network specify the IP address of the local router interface as their default gateway. Routers also serve other beneficial functions as follows: • They provide broadcast containment by limiting broadcasts to the local network. • They interconnect geographically separated locations. • The group users logically by application or department within a company, who have command needs or require access to the same resources. • They provide enhanced security by filtering unwanted traffic through access control lists.
  • 32. 39 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Cisco Routers Branch routers, shown in the figure, optimize branch services on a single platform while delivering an optimal application experience across branch and WAN infrastructures. Shown are the Cisco Integrated Services Router (ISR) 4000 Series Routers.
  • 33. 40 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Cisco Routers (Cont.) Network edge routers, shown in the figure, enable the network edge to deliver high- performance, highly secure, and reliable services that unite campus, data center, and branch networks. Shown are the Cisco Aggregation Services Routers (ASR) 9000 Series Routers.
  • 34. 41 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Cisco Routers (Cont.) Service provider routers, shown in the figure, deliver end-to-end scalable solutions and subscriber-aware services. Shown are the Cisco Network Convergence System (NCS) 6000 Series Routers.
  • 35. 42 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Cisco Routers (Cont.) Industrial routers, such as the ones shown in the figure, are designed to provide enterprise-class features in rugged and harsh environments. Shown are the Cisco 1100 Series Industrial Integrated Services Routers.
  • 36. 43 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Router Form Factors Cisco 900 Series: This is a small branch office router. It combines WAN, switching, security, and advanced connectivity options in a compact, fanless platform for small and medium-sized businesses.
  • 37. 44 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Router Form Factors Cisco ASR 9000 and 1000 Series Aggregation Services Routers: These routers provide density and resiliency with programmability, for a scalable network edge.
  • 38. 45 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Router Form Factors Cisco Network Convergence System 5500 Series Routers: These routers are designed to efficiently scale between large data centers and large enterprise networks, web, and service provider WAN and aggregation networks.
  • 39. 46 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Router Hardware Router Form Factors Cisco 800 Industrial Integrated Services Router: This router is compact and designed for harsh environments.
  • 40. 47 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11.5 Module Practice and Quiz
  • 41. 48 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz Packet Tracer - Compare Layer 2 and Layer 3 Devices In this Packet Tracer activity, you will use various commands to examine three different switching topologies and compare the similarities and differences between the 2960 and 3650 switches. You will also compare the routing table of a 4321 router with that of a 3650 switch.
  • 42. 49 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz What did I learn in this module? • The Cisco Borderless Network provides the framework to unify wired and wireless access, and is built on a hierarchical infrastructure of hardware that is scalable and resilient. • Two proven hierarchical design frameworks for campus networks are the three-tier layer and the two-tier layer models. • The three critical layers within these tiered designs are the access, distribution, and core layers. • Implement redundant links between critical devices and between access layer and core layer devices. • Implement multiple links between equipment, with either link aggregation (EtherChannel) or equal cost load balancing, to increase bandwidth. • Use a scalable routing protocol and implementing features to minimize the routing table size. • Implement wireless connectivity to allow for mobility and expansion.
  • 43. 50 © 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Module Practice and Quiz What did I learn in this module? (Cont.) • There are campus LAN, cloud-managed, data center, service provider, and virtual networking witches. • Form factors for switches include fixed configuration, modular configuration, and stack • Routers use the network portion (prefix) of the destination IP address to route packets to the proper destination. • Routers select an alternate path if a link or path goes down. • Cisco has several categories of routers including branch, network edge, service provider and industrial.