Solved: fib, adjacenct table and types of adjacency

sarahr202 · ‎12-08-2008

hi every body!

I have a question about types of adjacency.

There are different types of adjacency such as:

glean adjacency, throttling adjacency, null adjacency,drop adjacency,discard adjacency and punt adjacency.

My questions is if these adjacencies can only be found in adjacenct table or they can also be found in fib table.

thanks a lot!

Jon Marshall · ‎12-08-2008

Sarah

The FIB is pretty much the same as the Routing table with a pointer to the next-hop address/interface in the adjacency table.

The types of adjacency are only relevant in the adjacency table as far as i understand it. A good example of how these different types are used are contained in this doc -

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml#express

see the "Glean Adjacencies" paragraph for an example.

Jon

View solution in original post

xcz504d1114 · ‎12-08-2008

The forwarding information base is used to make prefix-based switching decisions, it is one part of the CEF process.

The other part of the CEF process is the adjacency table, the adjacency table maintains L2 next hop addresses for all FIB entries.

The tables work together to form the CEF process but are stored seperately.

http://www.cisco.com/en/US/products/hw/routers/ps167/products_tech_note09186a00801e1dc2.shtml

Jon Marshall · ‎12-08-2008

Sarah

The FIB is pretty much the same as the Routing table with a pointer to the next-hop address/interface in the adjacency table.

The types of adjacency are only relevant in the adjacency table as far as i understand it. A good example of how these different types are used are contained in this doc -

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml#express

see the "Glean Adjacencies" paragraph for an example.

Jon