Network Building Blocks – The Distribution Layer

Terry Slattery
Principal Architect

I recently attended a Cisco event billed as a ‘mini-Networkers’ in Columbia, MD. It was a full day of Cisco presentations about a variety of technologies and was attended by around 120 people. During the presentations, one obvious point was made that warrants stating more frequently:

The distribution layer in network building blocks isolates the core network from changes that occur in the access layer.

The idea is to have a stable core network where there are very few spanning tree or routing changes. Each STP or routing change causes a reconvergence, potentially affecting the efficiency of packet forwarding engines. Cisco’s SRND (Solution Reference Network Design) guides describe the network designs that best achieve efficient operation and ease of troubleshooting.

I recommend that you collect and use these guides.



Re-posted with Permission 

NetCraftsmen would like to acknowledge Infoblox for their permission to re-post this article which originally appeared in the Applied Infrastructure blog under


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