I have a router which receives multicast traffic from the source over a multicast LSP(signaled by LDP):

root@PE3> show pim join detail                  
Instance: PIM.master Family: INET
R = Rendezvous Point Tree, S = Sparse, W = Wildcard

    Flags: sparse,spt
    Upstream protocol: MLDP
    Upstream interface: Pseudo MLDP           
    Downstream neighbors:
        Interface: ge-0/0/3.0             
        Interface: ge-0/0/1.0 (assert winner)

Instance: PIM.master Family: INET6
R = Rendezvous Point Tree, S = Sparse, W = Wildcard


As seen above, the Upstream interface is Pseudo MLDP.

I can confirm the multicast traffic on the MPLS core-facing interface with packet capture:

00:42:19.767009 02:06:04:0e:ff:f0 > 02:06:06:0e:ff:f0, ethertype MPLS unicast (0x8847), length 102: MPLS (label 300720, exp 0, [S], ttl 97)
        (tos 0x0, ttl 98, id 0, offset 0, flags [DF], proto ICMP (1), length 84) > ICMP echo request, id 30014, seq 11171, length 64

Those packets are routed via ge-0/0/1.0 as they should:

root@PE3> show route forwarding-table label 300720                    
Routing table: default.mpls
Destination        Type RtRef Next hop           Type Index    NhRef Netif
300720             user     0                    indr  1048577     2
                                                 comp      631     1

Routing table: __mpls-oam__.mpls
Enabled protocols: Bridging, Single VLAN, Dual VLAN, 
Destination        Type RtRef Next hop           Type Index    NhRef Netif
default            perm     0                    dscd      545     1


However, they should also be routed via the ge-0/0/3.0 as seen in the output of show pim join detail, but there is not even an entry in the inet.1 table for,

root@PE3> show route table inet.1 

inet.1: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both        *[Multicast/180] 05:10:43
                      MultiResolve       *[Multicast/180] 05:10:43
                      MultiDiscard        *[Multicast/180] 05:10:43


Interfaces ge-0/0/3.0 and ge-0/0/1.0 are connected to different broadcast domains and in both broadcast domains there are listeners subscribed to

What might cause such behavior?

  • 1
    Are you using PIM SSM or PIM ASM?
    – manish ma
    Jun 14, 2021 at 13:25
  • I'm using PIM SSM.
    – Martin
    Jun 14, 2021 at 13:27


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