Question On FIB Table

hitmenhitmen Banned Posts: 133
There are 4 components in a FIB table: ip address, next hop ip, next hop mac and the egress port.

How does the FIB table know what the next hop mac is? Are there different mac address on the same device but on different ports?

I am confused here. Any help appreciated.


  • SecurityThroughObscuritySecurityThroughObscurity Member Posts: 212 ■■■□□□□□□□
    It doesn't.
    The FIB responsible for ensuring that all recursive routes are resolved. The FIB is a data structure called mtrie, each level of the mtrie is called a node, the final node is called a leaf. The leaf points to the adjacency table.
    The adjacency table is created to contain all connected next hops.
    As soon as a neighbor becomes adjacent, a link layer header (dest MAC, source MAC, ethertype) used to reach that neighbor is created and stored in the table.

    The FIB - sh ip cef
    The adjacency table - sh adjacency detail
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