MPLS Fundamentals

Distributed CEF (DCEF)

One of the main advantages of CEF is that it can be used in a distributed manner. Some Cisco routers use a central CPU without any form of decentralized or distributed intelligence. An example of such a router is the 7200 series router. CEF in this platform can only use the central CPU and as such can forward traffic by the CPU or in interrupt mode. Other hardware—such as the 7500 or GSR 12000 series router—has distributed intelligence and CPUs. Therefore, the router can distribute the burden of forwarding traffic through CEF by using the distributed CPUs to forward traffic without interrupting the central CPU. To achieve the distributed forwarding, both the CEF and adjacency table have to be distributed to these distributed ...