| The distribution layer provides
boundaries for different types of traffic such as broadcast and
multicast traffic. This is also where inter-VLAN routing often
occurs.
The distribution layer often consists
of a combination of high-end switches and Route Processors. Because
of its Layer 3 capabilities, the distribution layer becomes the
demarcation between networks in the access layer and networks in the
core. Each wiring-closet hub corresponds to a logical network or
subnet that connects to the Route Processor, thus allowing the Route
Processors in the distribution layer to provide broadcast control
and segmentation as well as terminating collision domains.
The switch/Route Processor model is
straightforward to configure and maintain because of its inherent
modularity. Each Route Processor within the distribution layer is
programmed with the same features and functionality. Common
configuration elements can be copied across the layer, allowing for
predictable behavior and ease of troubleshooting.
|