Implict null label number 3, failed to find and believe it

[mukupatil]

Implict null label number is 3 but when i tried debug and wireshark i failed to see it.

Q. If it is advertise as a label value 3 then why i did not find it in Wireshark as well as in "debug mpls ldp binding"? Maybe i have overlooked it

Q. Is there a way i see this label value?

Thanks in advance , because i know you experts knows where I am wrong

[Luc De Ghein · Accepted solution]

Hi,

Depending on the operating system and the command used, it will be shown as either "imp-null" (or something very similar) or "3". It is mostly"impl-null" though.

In Wireshark it should always be "3".

debug mpls ldp binding:

*Jan  9 07:34:25.677: tib: 10.1.5.0/24:: learn binding 1 from 10.100.1.4:0

*Jan  9 07:34:25.677: tib: a new binding to be added

*Jan  9 07:34:25.677: tagcon: tibent(10.1.5.0/24): label imp-null from 10.100.1.4:0 added    <<<

*Jan  9 07:34:25.677: tib: next hop for route 10.1.5.0/24(0, 10.1.6.4, Et3/0) is mapped to peer 10.100.1.4:0

show command:

IR2#show mpls ldp bindings  10.1.5.0 24

  lib entry: 10.1.5.0/24, rev 10

        local binding:  label: 19

        remote binding: lsr: 10.100.1.4:0, label: imp-null   <<<

Wireshark:

Thanks,

Luc

[mukupatil]

Hello Luc,

Thanks I really appriciate your help, now its crystal clear.

I have unnoticed wireshark Label TLV , I  can see it in wireshark  output

Thanks,

Mukesh