Company has implemented numerous multilayer switches that utilize FIB tables. Which
statement is true about the Forward Information Base (FIB) table?

A.
The FIB is derived from the IP routing table and is optimized for maximum lookup
throughput.

B.
The FIB table is derived from the Address Resolution Protocol table, and it contains Layer
2 rewrite (MAC) information for the next hop.

C.
When the FIB table is full, a wildcard entry redirects traffic to the Layer 3 engine.

D.
The FIB lookup is based on the Layer 2 destination MAC address.

E.
None of the other alternatives apply

Explanation:
The Layer 3 engine (essentially a router) maintains routing information, whether from static
routes or dynamic routing protocols. Basically, the routing table is reformatted into an
ordered list with the most specific route first, for each IP destination subnet in the table. The
new format is called a Forwarding Information Base (FIB) and contains routing or forwarding
information that the network prefix can reference.
In other words, a route to 10.1.0.0/16 might be contained in the FIB, along with routes to
10.1.1.0/24 and 10.1.1.128/25, if those exist. Notice that these examples are increasingly
more specific subnets. In the FIB, these would be ordered with the most specific, or longest
match, first, followed by less specific subnets. When the switch receives a packet, it can
easily examine the destination address and find the longest match entry in the FIB.
The FIB also contains the next-hop address for each entry. When a longest match entry is
found in the FIB, the Layer 3 next-hop address is found, too.