Default route received from Route Reflector did not get installed in BGP routing table????

Danny To · ‎10-07-2015

This issue is involved a route reflector (ASR1001x running "universalk9.03.12.00a.S.154-2.s0a-std.SPA.b" code and its 2 RR client PE1 and PE2 (both ASR9010 running IOS XR 5.3.1 with all the necessary SMUs)

PE1 received default route through eBGP, advertised to the Router reflector and Route reflector reflected back to PE2.

PE2 received the default route 0.0.0.0 with the correct next hop but for some unknown reasons, it dropped the best path indicator ">" and thus did not install it in the BGP routing table.

It should be pointed out that for other routes under different RD, this was not an issue.

Any ones experienced similar situations? thx

Nagendra Kumar Nainar · ‎10-07-2015

Hi,

From PE1, RR and PE2, can you get "show ip bgp vpnv4 <prefix>"?.

Danny To · ‎10-07-2015

On PE2,

(IOS XR) show bgp vrf <name> 0.0.0.0 ,

!!!!no route found.!!!!

show bgp vpnv4 unicast all neigh <route_reflector addr> received routes | incl 0.0.0.0

!!!noted that there was no ">" in front of the route

On RR,

(IOS) show ip bgp vpnv4 all neigh <PE2 addr> advertised-routes | incl 0.0.0.0

!!!noted that there was ">" in front of the route

On PE1,

default route was learned from an eBGP peer, so there is no issue here.

Sorry, we are in the process of changing the lab topology a bit so can't get the exact commands done at the moment. will post it once it is back to operational. thanks for the reply.

Danny To · ‎10-08-2015

Lab topology changed done. diagram attached.

Note: PE1 167.54.0.42 - PE2 167.54.0.43 - RouteReflector 167.54.0.132

Also link between PE2 and it eBGP peer on AS64996 is shutdown. Thus default route only comes in through PE1.

Here are the relevant commands and outputs for the devices in this problem:

Paths: (1 available, best #1)
Advertised to PE update-groups (with more than one peer):
0.2
Path #1: Received by speaker 0
Advertised to PE update-groups (with more than one peer):
0.2
64996 11079 64997 2653 2665 2675 577 577
167.39.17.129 from 167.39.17.129 (192.168.20.20)
Origin IGP, localpref 70, valid, external, best, group-best, import-candidate
Received Path ID 0, Local Path ID 1, version 1230
Community: 64996:100
Extended community: RT:2665:8001
-------------------------------------------

bar.bar1.vrr1#show ip bgp vpnv4 all neighbors 167.54.0.42 routes | incl 0.0.0.0
*>i 0.0.0.0 167.54.0.42 70 0 64996 11079 64997 2653 2665 2675 577 577 i

bar.bar1.vrr1#show ip bgp vpnv4 all neighbors 167.54.0.43 advertised-routes | incl 0.0.0.0
*>i 0.0.0.0 167.54.0.42 70 0 64996 11079 64997 2653 2665 2675 577 577 i

---------------------------------------------

RP/0/RSP0/CPU0:bar.bar1.pe2#show bgp vpnv4 unicast neigh 167.54.0.132 received routes | incl 0.0.0.0
Thu Oct 8 21:32:56.482 EDT
* i0.0.0.0/0 167.54.0.42 70 0 64996 11079 64997 2653 2665 2675 577 577 i

!!!!!Noted above that the best route ">" indicator was missing on the 0/0 route received by PE2 !!!!!

RP/0/RSP0/CPU0:bar.bar1.pe2#show bgp vpnv4 unicast neigh 167.54.0.132 routes | incl 0.0.0.0

RP/0/RSP0/CPU0:bar.bar1.pe2#show bgp vrf v301:internet-agg2 0.0.0.0
Thu Oct 8 21:41:58.000 EDT
% Network not in table

Danny To · ‎10-09-2015

The problem has been identified. It has to do with the way the vrf import/export between the PEs. No further followups are needed for this posting.

Thanks.