Access Layer for the Campus Network

Access Layer for the Campus Network
In a campus network, the Access layer is where users gain access to the network, and it is
the first device they connect to. This is usually a layer 2 switch with high port density that
connects users on a floor, or part of a floor, to a Distribution layer switch. This is where
layer 2 access control using VLAN access control lists (VACLs) is performed and optionally
packets can be marked.
The marking or coloring of packets is used to identify traffic flows and give that traffic the
required priority or level of service that it needs. For example, FTP packets can be marked as
Access Layer Distribution Layer Core Layer
Three-Layer Hierarchical Design Model
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the lowest priority and voice packets as the highest priority. This way, the FTP or other lower
priority packets on congested links will not delay the voice packets