This article explains the condition that when a routing-instance is deactivated, the update of the BGP withdraw packet will not be generated.

The problem related to a simple topology with router A and router B is described below:

+----------+          +----------+
| router A +----------+ router B |
+----------+          +----------+

Router A is the BGP speaker, which advertises the VPN prefix 192.168.0.0/24 to router B.

When the VPNA routing-instance on router A was deactivated:

edit logical-systems routerA
deactivate routing-instances VPNA_Receive
deactivate routing-instances VPNA_Adverti
commit synchronize

And then an attempt was made to show the BGP prefix on both Router A and Router B, conflicting results were obtained.

user@T1600-re1> show route advertising-protocol bgp 2.2.2.2 192.168.0.0/24 logical-system routerA
<<<<<< There was no BGP prefix 192.168/24 being advertised.

user@T1600-re1> show route receive-protocol bgp 1.1.1.1 logical-system routerB

bgp.l3vpn.0: 4 destinations, 4 routes (4 active, 0 holddown, 0 hidden)
Prefix            Nexthop        MED     Lclpref    AS path
1.1.1.1:100:192.168.0.0/24
*                 1.1.1.1        100     I

user@T1600-re1> show route 192.168/24 logical-system routerB

bgp.l3vpn.0: 4 destinations, 4 routes (4 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

1.1.1.1:100:192.168.0.0/24

*[BGP/170] 00:17:39, localpref 100, from 1.1.1.1
AS path: I, validation-state: unverified
> to 10.0.0.1 via xe-0/3/0.0, label-switched-path to-routerA
  to 10.0.0.5 via xe-5/1/4.0, label-switched-path to-routerA

Deactivating the routing instance before deleting all related configurations results in the BGP prefix un-withdraw to be interpreted as misconfiguration.

When a routing instance is deleted, all references to the routing instance and its RIBs should also be deleted.

In case where a rib-group is still referencing VPNA_Receive.inet.0 and VPNA_Adverti.inet.0, there will be no update advertisement from the BGP neighbor.

rib-groups {
    VPNA-R-TO-A {
        import-rib [ VPNA_Receive.inet.0 VPNA_Adverti.inet.0 ];
    }
}

Confirm Cause

To confirm the issue, use the following commands:

- show route advertising-protocol bgp x.x.x.x
- show route receive-protocol bgp x.x.x.x
- show route x.x.x.x
- show route x.x.x.x extensive

Before deactivating the routing instance, deactivate or delete all relative configurations such as rib-group.

edit logical-systems routerA
deactivate routing-instances VPNA_Receive
deactivate routing-instances VPNA_Adverti
deactivate routing-options rib-group VPNA-R-TO-A  commit synchronize

2020-10-13: Article checked for accuracy; article found to be valid and relevant; minor non-technical changes made