traceroute reports remote PE MPLS label

[tomc.pnnl]

Consider the diagrammed MPLS configuration

CE1 .a -- .b PE1 -- P1 -- P2 -- PE2 .c -- .d CE2 .e

and "no mpls ip propagate-ttl" configured at PE1, P1, P2, and PE2.

A trace route from CE1 to CE2 reports a MPLS label when egressing PE2:

Type escape sequence to abort.
Tracing the route to .e
VRF info: (vrf in name/id, vrf out name/id)
1 .b 21 msec 16 msec 11 msec
2 .c [MPLS: Label 19 Exp 0] 11 msec 19 msec 10 msec
3 .d 8 msec * 25 msec

In other examples, I thought PE2 would not show in a traceroute. Why in my case is a label being leaked? What can I do to hide it?

Thanks,

[balaji.bandi]

You should not see when you configured "no mpls ip propagate-ttl" configured at PE1, P1, P2, and PE2.

what device is this, try clear LDP session after adding the above command  and re-visit device config and test

here is the reference :

https://www.cisco.com/c/en/us/support/docs/multiprotocol-label-switching-mpls/mpls/26585-mpls-traceroute.html

[tomc.pnnl]

Thanks. I did clear the ldp sessions and reviewed

https://www.cisco.com/c/en/us/support/docs/multiprotocol-label-switching-mpls/mpls/26585-mpls-traceroute.html

[Georg Pauwen]

Hello,

could be a bug. What device is the one sending the label ?

--> 2 .c [MPLS: Label 19 Exp 0] 11 msec 19 msec 10 msec

Post the output of 'sh ver' from that device.

[balaji.bandi]

is this LAB (kinda virtual ) or real gear.

if real gear kindly posts the device versions and what model of all device.

other input required what is the outcome when you do traceroute  CE2 to CE1?

[MHM Cisco World]

I think this is the normal 

trace route will show

ingress PE

egress PE

CE

 no mpls ip propagate-ttl

make P hidden from trace route.

why egress PE?

because of label is 3 from last P, PE will do IP lockup and reduce the TTL which make it 0 and send TTL exceed to CE.