Dedicated Route Reflectors

Fri Sep 11 23:41:54 UTC 2009

On 11 Sep, 2009, at 09:30, Serge Vautour wrote:

> Hello,
>
> We're in the process of planning for an MPLS network that will use  
> BGP for signaling between PEs. This will be a BGP free Core (i.e. no  
> BGP on the P routers). What are folks doing for iBGP in this case?  
> Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some  
> outlining PEs? Are folks using dedicated/centralized Route  
> Reflectors (redundant of course)? What about using some of the P  
> routers as the Centralized Route Reflectors? The boxes aren't doing  
> much from a Control Plane perspective, why not use them as Route  
> Reflectors.

serge,

you can, and probably should, segment your mpls signalling ibgp from  
your internet/peering ibgp.  in other words, on your pe, you configure  
ipv4/ipv6 bgp sessions to your peering/transit routers, then you  
configure mp-bgp sessions to three or four mpls vpn route reflectors.   
the mpls route reflectors do not participate in the actual routing of  
any packets (they don't set next-hop-self, only the pe routers would),  
their only function is to reflect the vpn signalling between disparate  
pe boxen.

similarly, if you have a very large number of pe routers, you can  
setup three or four boxes to reflect internet/customer routes...these  
boxes also would not route any packets, they would just reflect the  
non-mpls bgp sessions (they don't set next-hop-self, only the pe/ 
transit/peering router do).

alternately, if you have local transit/peering routers at every pe  
site, then you can mesh all the transit/peering routers and have the  
local pe routers be rr clients of that site's transit/peering routers

hth
/joshua