Targeted ldp session issue in IOSXR

[qus83]

Hello

i have issue in targeted hello for non directly connected peer

show mpls ldp discovery

Targeted Hellos:
x.x.x.x-> x.x.x.x (active), xmit
Established: N/A

remote router 

x.x.x.x -> x.x.x.x (active/passive), xmit/recv
LDP Id: x.x.x.x:0
Hold time: 90 sec (local:90 sec, peer:90 sec)
Established: May 26 05:31:33.063 (6w1d ago)

issue PW doesn't come up

PW: neighbor x.x.x.x, PW ID 222, state is down ( provisioned ) (Segment-down)

[qus83]

Did you have a chance to verify why udp traffic to port 646 does not make it in one direction?

I did but no telnet 

[Harold Ritter]

Hi @qus83 ,

The telnet is to verify the TCP connectivity to port 646 between the two PEs, not the UDP connectivity to port 646.

Do you use any inbound or outbound ACL on the core facing interface on the two PEs?

Regards, 

[qus83]

I don't think it's an ACL ISSUE because it works fine with other PEs

[MHM Cisco World]

In ios xr check if you disable mpls label for host prefix since you use Lo for xconnect.

MHM

[Harold Ritter]

Hi @MHM Cisco World ,

The OP mentioned that the "mpls ping" works from loopback to loopback. 

The issue is somewhere else. It appears that the targeted LDP hellos are not making it from one PE to the other. This is probably where he should focus for now.

Regards,

[MHM Cisco World]

 for my suggestion he can easily check

Show mpls forwarding 

Check if the LO have label (ingress and egress) 

MHM

[Harold Ritter]

The "ping mpls" already confirmed that the LSP works fine between the two PEs.

Regards,

[Harold Ritter]

Hi @qus83 ,

You need to focus on why the ldp targeted LDP hello packets are not being received then. This is at the center of this issue.

You could use the following command to see what LDP hello packets are being received on the PE that only sees xmit on the "show mpls ldp discovery". Please use it carefully if you have lots of neighbors on this PE.

"debug mpls ldp discovery hello receive"

Regards,