Description

This article explains an issue with SRX series devices working in packet mode and configured with MPLS multicast routing.

Symptoms

In an environment using MPLS multicast routing, it is observed that SRX does not update it's TED database correctly after a topology change or a link failure scenario.

 

Sample topology:

 

Below are the TED database entries when everything is connected:

 

root@srx> show ted database 1.2.3.4

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  To: 5.6.7.9, Local: 50.50.50.14, Remote: 50.50.50.13

   Local interface index: 0, Remote interface index: 0

 

root@core-router-1> show ted database 1.2.3.4   

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  To: 5.6.7.9, Local: 50.50.50.14, Remote: 50.50.50.13

   Local interface index: 0, Remote interface index: 0

 

root@core-router-2> show ted database 1.2.3.4   

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  To: 5.6.7.9, Local: 50.50.50.14, Remote: 50.50.50.13

   Local interface index: 0, Remote interface index: 0

 

root@access-router> show ted database 1.2.3.4 

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  To: 5.6.7.9, Local: 50.50.50.14, Remote: 50.50.50.13

   Local interface index: 0, Remote interface index: 0

**********************************************************************************************************************************

Now, if we disconnect the link between the access router and the core router-2, we see that TED databases on all routers do reflect this path change, but the TED database on the SRX does not.

 

root@srx> show ted database 1.2.3.4 

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  To: 5.6.7.9, Local: 50.50.50.14, Remote: 50.50.50.13

   Local interface index: 0, Remote interface index: 0

 

root@core-router-1> show ted database 1.2.3.4   

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

 

root@core-router-2> show ted database 1.2.3.4   

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

  

root@access-router> show ted database 1.2.3.4

TED database: 0 ISIS nodes 6 INET nodes 0 INET6 nodes

ID              Type Age(s) LnkIn LnkOut Protocol

1.2.3.4        Rtr  291  2   2 Exported OSPF(4)

  To: 5.6.7.8, Local: 50.50.50.10, Remote: 50.50.50.9

   Local interface index: 0, Remote interface index: 0

 

In the traceoptions file, we do see that SRX does receive a 'delete' entry from the core routers, but does not actually delete the entry.

Solution

This issue can be seen if any or all of the below conditions are met:

  • On any Junos platform
  • MPLS usage with traffic engineering
  • BGP-LS is used for database updates
  • Any network event that can trigger an IGP database update like a link flap or failure

The issue will surface every time the triggers are met. Any IGP (Interior Gateway Protocols) database update event triggered by changes on an IGMP enabled interface like flap or disconnections are not updated on the TED table, leaving unavailable routes that if used to route traffic causes blackholing. the database gets updated only after the affected link comes up. Both IGMP and BGP-LS are mandatory triggers as the IGMP floods the database, but BGP-LS is the responsible of updating the TED database.

The fix will be available in evo:25.2R2-EVO, evo:26.1R1-EVO, junos:23.4R2-S7, junos:25.2R2, junos:26.1R1.

Modification History

2025-11-20 : Article Created

2026-06-15: Information updated