Route Reflectors

fbarreras · ‎01-03-2003

Lets say I entered the following commands

Router BGP 100

neighbor 167.55.66.6 remote-as 100

neighbor 167.55.66.6 route-reflector-client

neighbor 167.55.55.5 remote-as 100

neighbor 167.55.55.5 route-reflector-client

I then decide to add another Route Reflector for redundancy. I would assume that I would enter the same commands on this second Route Reflector. What dictates which would be the primary route reflector upon power up of both router reflectors? With OSPF, the DR and BDR are selected with highest router ID and/or highest priority. I haven't found anything written that will answer this for me. By the way, I am preparing for CCNP Routing exam. Thanks.

jhalldn · ‎01-03-2003

Hi,

In the second RR, you will fill the same commands, but also you will configure(in both) a iBGP session between the two RRs. Both will treat eachother as a ordnarie iBPG speaker. Both RR are active and theres no primary or secondary, just the one with thebest route the prefered desitination. Configuring reflectors is just as full mesh and will act just as BGP. Theres some optional attributes for checking for loops.

Every BGP speaker has a RID, router ID, its normally carried as the originator for the route/prefix. RID is the IP address of your speaker/interface and can be used when selecting a path in BGP decison. The lowest RID(IP adress) is prefered.

fbarreras · ‎01-03-2003

Thanks for your response. Does that mean that if I had a cluster with two route reflectors and multiple clients, that each of the clients would be served by the route reflector with the preferred route? So a client can be assigned multiple reflectors. Thanks, I know I sound confused.

jhalldn · ‎01-04-2003

Yes, because RR is just a way to minimze the full mesh in a AS.

All the routers talk to eachother in a full mesh, but with RR, the RR reflects all routes for the clients. If you would have only one RR in your cluster and it went down...nothing would work within your iBGP. If you configure multiple RR and one goes down, the client are still having full iBGP routing table.

fbarreras · ‎01-09-2003

Thanks for your input

dimplejaral · ‎06-07-2010

hello,

So u mean to say if u have two RR suppose RR1 and RR2 and RR1 has router id 10.255.254.1 and R2 has router id 10.255.255.1. here the client will send and reacive update from Lower RID means from RR1....Help me if i am wrong..

Thanks

dims..

Jaya Prakash · ‎06-15-2010

Hi,

It will follow the normal BGP route selection criterion for selecting the best path. If all the attributes are same then it will take the decision based on the Router ID. Prefers the route comes from the router with lowest router-ID.

-JP