Specifications

CHAPTER 1

Campus Network Design

n Distribution: Aggregation point for access switches. Provides availability, QoS, fast path recovery, and load balancing.

n High availability through redundant distribution layer switches providing dual paths to the access switches and to

core switches. Use of FHRP protocols to ensure connectivity if one distribution switch is removed.

n Routing policies applied, such as route selection, filtering, and summarization. Can be default gateway for access

devices. QoS and security policies applied.

n Segmentation and isolation of workgroups and workgroup problems from the core, typically using a combination

of Layer 2 and Layer 3 switching.

n Core: The backbone that provides a high-speed, Layer 3 path between distribution layers and other network

segments. Provides reliability and scalability.

n Reliability through redundant devices, device components, and paths.

n Scalability through scalable routing protocols. Having a core layer in general aids network scalability by provid-

ing gigabit (and faster) connectivity, data and voice integration, and convergence of the LAN, WAN, and MAN.

n No policies such as ACLs or filters that would slow traffic down.

A set of distribution devices and their accompanying access layer switches are called a switch block.

The Core Layer

Is a core layer always needed? Without a core layer, the distribution switches must be fully meshed. This becomes more

of a problem as a campus network grows larger. A general rule is to add a core when connecting three or more buildings

or four or more pairs of building distribution switches. Some benefits of a campus core are:

n Adds a hierarchy to distribution switch connectivity

n Simplifies cabling because a full-mesh between distribution switches is not required

n Reduces routing complexity by summarizing distribution networks

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CCNP SWITCH 642-813 Quick Reference by Denise Donohue

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