Hi all !
About CEF !
Cisco white paper said:
CEF can be enabled in one of two modes:
Central CEF mode − When CEF mode is enabled, the CEF FIB and adjacency tables reside on the route processor, and** the route processor performs the express forwarding.** You can use CEF mode when line cards are not available for CEF switching, or when you need to use features not compatible with distributed CEF switching.
Distributed CEF (dCEF) mode − When dCEF is enabled, line cards maintain identical copies of the FIB and adjacency tables. The line cards can perform the express forwarding by themselves, relieving the main processor − Gigabit Route Processor (GRP) − of involvement in the switching operation. This is the only switching method available on the Cisco 12000 Series Router.
dCEF uses an Inter−Process Communication (IPC) mechanism to ensure synchronization of FIBs and adjacency tables on the route processor and line cards.

While the CEF purpose is to offer the capability to switch the packets via device in an efficient way when keeping the load on a router processor as low.
so when the central cef mode is enabled the route processor performs the express forwarding, isn't it still make the router processor work more or i mean it will keep the load on a router processor as high...
It's confusing.. So Central CEF just have a little benefit than normal ?


  • Nvm. I found out that Router processor is different from the Route processor :dizzy:

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