Route Reflection

[mkhalil10]

Hi all

I have MPLS network with many PEs , I have decided to place route-reflectors (for both VPNv4 and VPLS AFs)

Due to installation and connectivity issues , I could not connect all my PEs to the new Ps , so I have cascaded PEs

My question is , is better to make the parent PE a route reflector and the parnet PE is a client for the P , or (as I already have IGP connectivity) make all the PEs whatever directly connected or cascaded clients to my Ps?

Thanks

BR,

Mohammad

[Peter Paluch]

Hi Mohammad,

I am not entirely certain if I understand your question completely. I am sure you know that route reflectors can be placed arbitrarily and they are not related in any way to the role of the router, whether it is a PE, a P, or - and this is often the best case - a totally separate and standalone router.

Perhaps you could sketch a simple figure of your network showing the options you are considering.

Best regards,
Peter

[mkhalil10]

Hi

Thanks for the kind reply

I mean , I have connections to my P router from several PEs , but some of my PEs are cascaded to my PE

PE1 -- PE2 -- P

So in this case , I can make P a route reflector to PE1 and PE2 , but is better to make PE2 a route reflector to PE1 and at the same time , PE2 is a route reflector client to P ?

As well , am thinking of deploying out-of-band route reflector , that is supposed to add some enhancement to my network right ?

Thanks again

BR,

Mohammad

[Peter Paluch]

Hi Mohammad,

So in this case , I can make P a route reflector to PE1 and PE2

So you are saying here that P would be a route reflector, and PE1 and PE2 would be its clients. Correct? If yes then sure, this would work.

but is better to make PE2 a route reflector to PE1 and at the same time , PE2 is a route reflector client to P

If I get you correctly there you want P to be a route reflector and PE2 its client, and you want PE2 to be another route reflector and PE1 its client, right? This would complicate things unnecessarily.

A common design to have two, ideally out-of-band, route reflectors at different places in your network - even a single route reflector would do but it is then a single point of failure - and these route reflectors would have all other routers as their clients. The two route reflectors would treat each other as non-clients (that is, neither would be a client of the other). Clients themselves would only need to have iBGP peerings toward the route reflectors.

Would this make sense?

Please be aware that route reflectors perform their own best path selection, and even though they can be aware of multiple best paths toward a particular VPN site, they will always advertise only a single best path. This could potentially break load balancing in your network if you have made use of it before, as instead of knowing multiple paths, clients will now learn only about a single best path as determined by the route reflector. There are ways to deal with this but you should at least be aware of this.

There is also the Ask the Expert session on BGP running here, with Vinit Jain responding, so it is the perfect time to ask him for details of this setup:

https://supportforums.cisco.com/discussion/12576981/ask-expert-configuring-and-troubleshooting-border-gateway-protocol-bgp

Best regards,
Peter