Core Layer

Core Layer
The
Core layer
is a high-speed data pump that is the backbone of the network and should not
be burdened by additional services. It receives traffic on one interface and quickly switches it to
the appropriate outbound interface to provide increased packet switching and an optimized
transport. The Core layer should not be marking or filtering any traffic but can use information
in the packets to enqueue traffic to ensure QoS across the backbone. The keys to a good Core
layer are redundancy, fast convergence, and independence from the connection technology (for
example, SONET, GigE, and ATM). The core in a WAN network looks different from the core
in a campus network because the first operates at layer 3 and the second operates at layer 2.