Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[T] No BGP update after routing-instance is deactivated

0

0

Article ID: KB27841 KB Last Updated: 13 Oct 2020Version: 3.0
Summary:

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

 

Symptoms:

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

 

Cause:

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

 

Solution:

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

 

Modification History:

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

 

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search