Design Review Template - NETS

Hierarchical (MultiLayer) Network
Design: An Overview
Overview
The hierarchical three tiered campus design has become the preferred architecture for most networks. The three
tiered architecture is comprised of an access layer that directly connect network users by means of switches,
normally placed in wiring closets positioned throughout the campus. Access layer switches are also connected to
a distribution layer. The distribution layer sites will have a number of access switches connected to it. The
number of access switches connected to the distribution layer is often determined by geographic proximity, such
as all the access switches in a building homing into one distribution site for that building. The distribution sites
normally consist of switches with layer 2 and layer 3 functions. The distribution layer switches are usually
deployed in pairs for system redundancy. The distribution layer switches are then connected to a core layer
switch. The core switches are also usually deployed in pairs for redundancy and may support layer 3 as well as
layer 2 functions. An overall campus design such as this might have a numerical profile of 8000 users connected
to 40 access switches that are then connected to 4 distribution sites that are finally connected to 1 core site.
Access
Distribution
Backbone
Core
Building block additions
Data Center
WAN Internet Remote Access
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