Configuring VRF resets PE-CE eBGP sessions?

[limtohsoon]

Hi Sir,

I'm configuring an MPLS PE router. It's a Cisco 7609, IOS version 12.2(18)SXF6.

The existing configuration has a VRF which runs eBGP with two CE routers. I just added the following additional commands to the VRF:

route-target import 65000:99

route-target export 65000:100

I observed following messages indicating the eBGP sessions been reset when I did "wri mem" on the 7609:

Feb 8 18:46:32: %PFINIT-SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router.

Feb 8 18:55:47: %BGP-5-ADJCHANGE: neighbor 172.18.252.2 vpn vrf TESTVRF Down VRF config change

Feb 8 18:55:47: %BGP-5-ADJCHANGE: neighbor 172.18.252.6 vpn vrf TESTVRF Down VRF config change

Feb 8 18:55:54: %PFINIT-SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router.

Feb 8 18:56:29: %BGP-5-ADJCHANGE: neighbor 172.18.252.2 vpn vrf TESTVRF Up

Feb 8 18:56:30: %BGP-5-ADJCHANGE: neighbor 172.18.252.6 vpn vrf TESTVRF Up

Feb 8 19:02:01: %PFINIT-SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router.

Feb 8 19:19:01: %PFINIT-SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router.

Feb 8 19:20:17: %PFINIT-SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router.

I did similar changes to another VRF in which the customer VLAN segments directly connected to the 7609. There's no complaint from this customer.

Please advise why this happened.

Thank you.

B.Rgds,

Lim TS

[mheusinger]

Hello Lim,

this is the default behaviour. In my opinion this is done to get all routes again into the BGP table and apply the new route-targets in BGP.

I also would appreciate a warning message BEFORE this is done automatically, but it does not exist.

By the way, there is no impact on OSPF, EIGRP and so on between PE and CE. Only BGP is affected. In case of IGPs between PE and CE it therefore might happen, that new RTs are not applied immediately. You might need to manually trigger this (clear commands).

Regards, Martin