BGP on CRS

[cisco_lad2004]

Dear all,

Any reason why following config would work on ISO XR3.8.4 and not 4.0.1 ?

on CRS-1 running 3.8.4, I a mable to have both IPv4 & IPV6 sessions up. howver on 4.0.1, as soon as address family IPv6 is added, v4 goes down...and v6 has not been able to be established. This a 6PE setup with MPLS / LDP toward score nodes. Below BGP seesions are towards a route reflector.

TIA

/Samir

router bgp 65101
bgp router-id 192.168.1.8
address-family ipv4 unicast
  redistribute connected
!
address-family ipv6 unicast
  redistribute connected
  allocate-label all

!

neighbor-group IBGP
  remote-as 65101
    update-source Loopback0
  address-family ipv4 unicast
   next-hop-self
  !
!
neighbor-group IPv6_IBGP
  remote-as 65101
  update-source Loopback0
  address-family ipv6 unicast
   next-hop-self
  !
  address-family ipv6 labeled-unicast
  !
!
neighbor 192.168.1.96
  use neighbor-group IBGP-PEER
  description SOUTH-RR1
  address-family ipv4 unicast
   use af-group IBGP-PEER
  !
  address-family ipv6 unicast
   use af-group IPv6_IBGP-PEER

[Giuseppe Larosa]

Hello Samir,

I would remove next-hop-self in all address families and I would look at route reflector logs, and may be at a moderate debug on it to understand what is happening

You may find out that the BGP RRS is sending a BGP notification claiming about an unexpected/ offending attribute TLV.

Also are these iBGP sessions? I see different AS numbers in the neighbor groups and at the router bgp process but I guess that is only a typing error

Check also if Ipv4 connectivity between BGP endpoints works during the ipv6 AF setup to exclude problems in the forwarding plane.

Hope to help

Giuseppe

[cisco_lad2004]

Many thanks Giuseppe !

Actually I think my config was not right, changed it to below config to supprt 6PE and now I can see both v4 & v6 prefixes. but sh bgp neighbor is only present for v4...where as with old config used on 3.8.4 CRS-1.

I am still puzzled with why was I able to get both prefixes as well as bgp neigbor established for old image.

So bottom line, am not really sure if my config is correct. I can see CEF labels for IPv6 prefixes. will be doing more configs tomorrow and should be able to test end to end connectivity.

Samir

neighbor 192.168.1.8
  remote-as 65101
  update-source Loopback0
  address-family ipv4 unicast
   next-hop-self
  !
  address-family ipv6 labeled-unicast
   next-hop-self