The Access Layer
The access layer has three goals:
Feed traffic into the network
Perform other edge functions
Access layer devices interconnect the high speed LAN links to the wide area links carrying traffic into the distribution layer. Access layer devices are the visible part of the network; this is what your customers associate with "the network."
Feeding Traffic into the Network
It's important to make certain the traffic presented to the access layer router doesn't overflow the link to the distribution layer. While this is primarily an issue of link sizing, it can also be related to server/service placement and packet filtering. Traffic that isn't destined for some host outside of the local network shouldn't be forwarded by ...