Avaya 8800 Planning And Engineering, Network Design page 73

Campus architecture
A three-tier campus architecture consists of an edge layer, a distribution layer, and a core layer.
• Edge layer: The edge layer provides direct connections to end user devices. These are
normally the wiring closet switches that connect devices such as PCs, IP phones, and printers.
• Distribution layer: The distribution layer provides connections to the edge layer wiring closets in
a three-tier architecture. This layer connects the wiring closets to the core.
• Core layer: The core layer is the center of the network. In a three-tier architecture, all
distribution layer switches terminate in the core. In a two-tier architecture, the edge layer
terminates directly in the core, and no distribution layer is required.
Important:
Avaya recommends that you do not directly connect servers and clients in core switches. If one
IST switch fails, connectivity to the server is lost.
Data center architecture
The tiered network architecture also applies to a data center architecture. In this case, the core and
distribution layers provide similar functions to those in a campus architecture, while the edge layer is
replaced by the server access layer:
• Server Access layer: The server access layer provides direct connections to servers.
• Distribution layer: The distribution layer provides connections to the server access layer in a
three-tier architecture.
• Core layer: The core layer is the center of the network. In a three-tier architecture, all
distribution layer switches terminate in the core. In a two-tier architecture, the server access
layer terminates directly in the core, and no distribution layer is required.
Example network layouts
The followingfigure shows a three-tiered campus architecture with edge, distribution,and core layers.
In addition, a server access layer is directly connectedto the core, representing a two-layer data
center architecture.
June 2016 Planning and Engineering — Network Design
Comments on this document? infodev@avaya.com
Network redundancy
73