Which Cisco Express Forwarding table or tables hold forwarding information?

A. FIB and adjacency tables only

B. adjacency tables only

C. FIB, RIB, and adjacency tables

D. FIB table only








 

Suggested Answer: A

Information conventionally stored in a route cache is stored in several data structures for Cisco Express Forwarding switching.
The data structures provide optimized lookup for efficient packet forwarding. The two main components of Cisco Express Forwarding operation are the forwarding information base (FIB) and the adjacency tables.
The FIB is conceptually similar to a routing table or information base. A router uses this lookup table to make destination-based switching decisions during Cisco
Express Forwarding operation. The FIB is updated when changes occur in the network and contains all routes known at the time. For more information, see the
FIB Overview section.
Adjacency tables maintain Layer 2 next-hop addresses for all FIB entries. For more information, see the CEF Adjacency Tables Overview section.
This separation of the reachability information (in the Cisco Express Forwarding table) and the forwarding information (in the adjacency table), provides a number of benefits:
The adjacency table can be built separately from the Cisco Express Forwarding table, allowing both to be built without any packets being process-switched.
The MAC header rewrite used to forward a packet is not stored in cache entries, so changes in a MAC header rewrite string do not require validation of cache entries.
Reference:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipswitch_cef/configuration/15-mt/isw-cef-15-mt-book/isw-cef-overview.html

This question is in 300-101 Cisco Implementing Cisco IP Routing (ROUTE) Exam
For getting Cisco Certified Network Professional (CCNP) Routing and Switching Certificate




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