10-20-2015 04:43 AM
Here is the scenario (Also attached the diagram)
(Internal network1 )-----CE1------------PE1------------MPLS(RR)------------PE2--------CE2---------(Internal network1)
Routing protocol is BGP everywhere i.e
Internal network -CE1
CE1-PE1
CE2-PE2
and CE2 to Internal network
Now both the internal network 1 and two are having same prefix 10.10.10.10 which they are advertsing to CE1 and CE2 respectively.
The customer wants these two prefixes to be received at both the routers.Like one from internal network to the CE1 and other from the CE2-CE1 via PE1 and PE2.
However due to the split horizon behaviour of BGP ,I am unable to see this prefix in one of the CEs.
As in he CE1 is receiving two routes one received from the PE1 and other from the CE2 ,however CE2 is not receiving the route from CE1.
This is due to the reason that ,when PE1 receives a route from CE1 it is already having another route which was received from PE2 ,so it is only considering that route.Hence it is not advertising this prefix to the RR due to split horizon.
Please not that the AS path for both the prefixes is different since we have different AS in both the internal networks.However we have the same AS number for the CEs and I am using as-override for this.
Can someone please suggest me how I could tweak the solution so that the customer received both the routes at both the locations.
Thanks.
10-21-2015 01:00 PM
Hi Sumit,
As you stated, this is normal behavior for this protocol. BGP will look at the recieved prefixes in the BGP table but only install the best route in the routing table.
If the customer just wants to make sure the CE is learning both prefixes, then a
"sh ip bgp" should prove that case.
I assume they are using one path for primary and one for backup? The only other BGP feature I can think of off the top of my head is BGP Multipath. But, you would need 2 WAN links on the same router to load share across the two BGP peers.
11-17-2015 01:15 AM
level 15 access to BGP Speaker?please contact me mabena.lukas@gmail.com
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide