The Campus Infrastructure module connects users within a campus to
the Server Farm and Edge Distribution modules. The Campus Infrastructure module
is comprised of Building Access and Distribution switches connected through the
campus backbone to campus resources.
A Campus Infrastructure module
includes these submodules:
-
Building Access submodule (also known as Building Access layer) –
Contains end-user workstations, IP Phones, and Layer 2 access switches that
connect devices to the Building Distribution submodule. The Building Access
submodule performs services such as support for multiple VLANs, Private VLANs
and establishment of trunk links to Building Distribution layer and IP Phones.
Each Building Access switch has connections to redundant switches in the
Building Distribution submodule.
-
Building Distribution submodule (also known as Building Distribution
layer) – Provides aggregation of Building Access devices, often using Layer
3 switching. The Building Distribution submodule performs routing, QoS, and
access control. Traffic generally flows through the Building Distribution
switches and onto the campus core or backbone. This submodule provides fast
failure recovery because each Building Distribution switch maintains two
equal-cost paths in the routing table to every Layer 3 network number. Each
Building Distribution switch has connections to redundant switches in the core.
Note deletion of Switch Block.
-
Campus Backbone submodule (also known as Building Core layer) –
Provides redundant and fast-converging connectivity between buildings, the
Server Farm and Edge Distribution modules. The purpose of the Building Core
submodule is to switch traffic as fast as possible from one module. Forwarding
decisions should be made at ASIC level whenever possible. Routing, ACLs and
processor based forwarding decisions should be avoided at the core and
implemented at Building Distribution devices whenever possible. High End Layer
2 or Layer 3 switches are used at the Core for high throughput with optimal
routing, QoS, and security capabilities available when needed.