Describe how a hierarchical network supports the voice, video and data needs of a small and medium-sized business.

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Chap 1 LAN Design Learning Objectives

• Describe how a hierarchical network supports the
  voice, video and data needs of a small and
  medium-sized business.
• Match the appropriate Cisco switch to each layer
  in the hierarchical network design model.

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Hierarchical Design Model

• The use of a hierarchical design model will make
  it easier to make changes to the network as the
  organization grows. Cisco currently recognize the
  following layers
• Access layer provides users in workgroups access
  to the network.
• Distribution layer provides policy-based
  connectivity.
• Core layer provides optimal transport between
  sites - the backbone.

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Hierarchical Design Model
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Hierarchical Design Model Access Layer

• Shared Bandwidth
• Switched Bandwidth
• MAC Layer filtering
• Micro-segmentation

The access layer is the entry point for user
workstations and servers to the network typical
devices being switches or hubs.
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Hierarchical Design Model Distribution Layer

• Aggregation of the wiring-closet connections
• Broadcast/multicast domain definition
• VLAN routing
• Any media transitions that need to occur (copper
  to FO)
• Security (ACLs)

• The purpose of this layer is to provide a
  boundary definition in which packet manipulation
  can take place.

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Hierarchical Design Model Core Layer

• Doesnt perform any packet manipulation - would
  slow down the switching of packets.
• Provide redundant alternate paths.
• Can be designed to use Layer 2 or Layer 3
  switching - ATM or Ethernet.

The core layer is a high-speed switching backbone.
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LAN Design Goals

• Scalability - Hierarchical networks scale very
  well, as the modularity of the design allows the
  replication of design elements as the network
  grows.
• Redundancy - As a network grows, availability
  becomes more important. Availability can be
  increased through easy redundant implementations
  with hierarchical networks.
• Performance - enhanced by avoiding the
  transmission of data through low-performing,
  intermediary switches.
• Security - Access layer switches can be
  configured with various port security options
  that provide control over which devices are
  allowed to connect to the network.
• Manageability - Each layer of the hierarchical
  design performs specific functions that are
  consistent throughout that layer easy to
  manage.
• Maintainability - Because hierarchical networks
  are modular in nature and scale very easily, they
  are easy to maintain.

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Switched LAN Design Principles

• Links between specific switches can be
  aggregated, which is called link aggregation.
  Link aggregation allows multiple switch port
  links to be combined so as to achieve higher
  throughput between switches.

• Redundancy is one part of creating a highly
  available network. Redundancy can be provided by
  doubling up the network connections between
  devices, or doublinge the devices themselves.

• Network diameter - number of devices that a
  packet has to cross before it reaches its
  destination a low number ensures low and
  predictable latency between devices.

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Converged Networks

• Many separate communications networks have
  evolved to support various different types of
  communication.
• Traditionally, data and voice networks remained
  separate.

Circuit Switch
Aggregate Link To PSTN
Traditional Phones/Video
Link IP Network
DCE
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Converged Networks
Convergence is the process of combining voice and
video communications on a data network.

• It is less expensive to implement a single
  network infrastructure than multiple network
  infrastructures.

Traditional Phones/Video
Link IP Network
DCE
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Considerations for Hierarchical Network Switches

• Traffic Flow Analysis - Traffic flow analysis is
  the process of measuring the bandwidth usage on a
  network and analyzing the data for the purpose of
  performance tuning, capacity planning, and making
  hardware improvement decisions.

Analysing the various traffic sources and their
impact on the network, allows more accurate
tuning and upgrading of the network to achieve
the best possible performance.
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Considerations for Hierarchical Network Switches
User community analysis - the process of
identifying various groupings of users and their
impact on network performance. The way users are
grouped affects issues related to port density
and traffic flow, which, in turn, influences the
selection of network switches

• Future Growth - 24-port switch has only 4 spare
  ports, so future growth of the department is not
  considered.
• A stackable or modular switches that can scale
  would probably be a better initial solution.

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Server Placement
Considerations for Hierarchical Network Switches

• Servers can be categorized as either enterprise
  servers or workgroup servers
• Enterprise servers support all the users on the
  network as it offers services, such as e-mail or
  Domain Name System (DNS).
• Workgroup servers support a specific set of users
  and offers services such as word processing and
  file sharing.

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Server Placement
Considerations for Hierarchical Network Switches
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LAN Design Goals - Documentation
Considerations for Hierarchical Network Switches
Topology Diagram
Cut Sheet
Addressing Map
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Switch Features Form Factors

• Fixed configuration - cant add features or
  options to the switch.

• Modular switches chassis allows for the
  installation of different numbers of modular line
  cards containing switch ports.

• Stackable switches - interconnected using a
  special backplane cable that provides
  high-bandwidth throughput between switches.

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Switch Features Port Density

• Port density is the number of ports available on
  a single switch.
• Modular switches can support very high port
  densities through the addition of multiple switch
  port line cards - Catalyst 6500 switch can
  support in excess of 1,000 switch ports on a
  single device.
• Without using a high-density modular switch, the
  network would need many fixed configuration
  switches to accommodate the number of devices
  that need network access. This approach can
  consume many power outlets and a lot of closet
  space.
• Fixed configuration switches may consume many
  additional ports for bandwidth aggregation
  between switches . Less of an issue with modular
  switches because the backplane of the chassis can
  provide the necessary bandwidth.

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Switch Features Port Forwarding

• Forwarding rates define the processing
  capabilities of a switch by rating how much data
  the switch can process per second.
• Wire speed is the data rate that each port on the
  switch is capable of attaining
• If the forwarding rate is not equal to or greater
  than the sum of the port speed, ports can not run
  at wire speed

24 x 100Mbps Switch Ports
Switch
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Switch Features Link Aggregation

• Link aggregation helps to reduce bottlenecks of
  traffic by allowing up to eight switch ports to
  be bound together for data communications,
  providing up to 8 Gb/s of data throughput when
  Gigabit Ethernet ports are used.
• Cisco uses the term EtherChannel when describing
  aggregated switch ports.

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Access Layer Switch Features

• Port Security
• VLANs
• Fast Ethernet/Gigabit Ethernet
• Power over Ethernet (PoE 802.3af)
• Link Aggregation
• Quality of Service (QoS)

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Distribution Layer Switch Features

• Layer 3 Support
• High Forwarding Rate
• Gigabit Ethernet / 10 Gigabit Ethernet
• Redundant Components
• Security Policies / Access Control Lists
• Link Aggregation
• Quality of Service (QoS)

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Core Layer Switch Features

• Layer 3 Support
• Very High Forwarding Rate
• Gigabit Ethernet / 10 Gigabit Ethernet
• Redundant Components
• Link Aggregation
• Quality of Service (QoS)

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Typical Network Switches
Access
Distribution
Core

• Catalyst 2960 series
• Catalyst 3560 series
• Catalyst 4000 series
• Catalyst 5000 series

• Catalyst 6500 series
• Catalyst 8500 series
• IGX 8400 series
• Lightstream 1010

• Catalyst 5000 family
• Catalyst 6000 family

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Chap 1 LAN Design Learning Objectives

• Describe how a hierarchical network supports the
  voice, video and data needs of a small and
  medium-sized business.
• Match the appropriate Cisco switch to each layer
  in the hierarchical network design model.

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Any Questions?