RIP question

rezaalikhani · ‎03-04-2007

Hi,

I am preparing itself for the CCNA exam, and currently reading the INTRO course. In the chapter 14 of the book, we can see a basic routing concepts.

My question:

In the differences between, RIP-1 and RIP-2, we have several options that among them I cannot understand two of them.

RIP-2 Includes a next-hop router IP address in its routing update: A router can advertise a route but direct any listeners to a different router on that same subnet.

and

Uses external route tags: RIP can pass information about routes learned from an external source and redistributed into RIP. Another router then can pass these external tags to that same routing protocol in a difference part of the network, effectively helping that other routing protocol pass information.

Please someone explain this differences to me.

Sorry about my bad English.

Thanks

Reza

amritpatek · ‎03-09-2007

For your first problem I will say that every RIP router shares its routing table (as broadcast) to every other router and so every router learns from others and makes its own routing decision. For second problem, redistribute is a feature used to share routing information between different protocols.

Following links may help you

http://www.pmg.com/otw_nwsl/97_w_rip1.htm

http://tools.ietf.org/html/rfc2453

royalblues · ‎03-10-2007

Reza,

For your 1st question

Lets consider there are 3 routers R1,r2 & R3 connected on the same LAN.

RIP is configured between only R1 and R2. R2 speak to R3 with a different routing protocol and does pass on some subnet information via this protocol. Then if you are running RIP v2 then the R2 wil advertise this over RIP with the next hop IP of R3 to be used directly.

Regarding your second question.

Tags are genreally used with BGP. These Tags are passed on and can be used by another instance of BGP running inside the network.

HTH, rate if it does

Narayan