Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

BGP multi-layer route-reflecrtor topology

Hello,

I'm trying to figure out if the multi-layer Route-Reflector topology would work for me. Let say we have 2 Route-reflectors RC-RR1 and RC-R2 and all other router are their reflect-clients. Now I'm getting a new router RC-.E001 and would like to set new level of Route-reflectors. I'd like that now the router  RC-E001 is a route-reflector client of RC-E002 (new level of RR) and RC-RR1, e.g. it will be a client of route-reflectors from different levels.

Is it possible? Which problems can arised?

BGP-RR-hyerchy.jpg

  • WAN Routing and Switching
Everyone's tags (2)
3 REPLIES

BGP multi-layer route-reflecrtor topology

Interesting question, although it will be much work to provide a truly detailed answer.

After looking at it briefly, my conclusion is this:

The resulting config will be invalid because any new router which is added to the AS must have a full mesh with all routers which are not route reflector clients. So RC-E002 will need bgp neighbor statements for both RC-RR1 and RC-RR2.

If this condition is not satisfied, inpredictable behavior will result (sub-optimal routing and non-functional redundancy).

The theory behind route reflectors is described in quite some detail in:

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#routereflectors

If you really want to go into the details, best is to build the setup in a lab (GNS3).

regards,

Leo

BGP multi-layer route-reflecrtor topology

Thank you for the link, I've read it already

this link is interesting as well

http://blog.sazza.de/?cat=22

you wrote: "RC-E002 will need bgp neighbor statements for both RC-RR1 and RC-RR2. "

of course BGP session stays between them, only change which I'd like to do is to add a new RC-E001 router as route-reflector client.

RC-E001 should be route-reflector client for RC-E002 and RC-RR1. It's not a problem to make it as route-reflector client for one of them, but for both in the same time - I'm not sure if it is allowed, because RC-E002 itself is a route-reflector client for RC-RR1

BGP multi-layer route-reflecrtor topology

Konstantin Dunaev wrote:

RC-E001 should be route-reflector client for RC-E002 and RC-RR1. It's not a problem to make it as route-reflector client for one of them, but for both in the same time - I'm not sure if it is allowed, because RC-E002 itself is a route-reflector client for RC-RR1


Which is why it has no purpose to do this. The main objective for using RR is to reduce the number of BGP peers.

Leo

434
Views
0
Helpful
3
Replies
This widget could not be displayed.