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mpls ping problem

nyami.david
Level 1
Level 1

Hello,

we have a PE router ( I will call it PE_X)  in our MPLS VPN backbone whose Loopback0 IP cannot be reached  using the the "ping mpls ipv4" command. An attempt to do so generates the following output:

 

R1# ping mpls ipv4 X.X.X.X/32

Sending 5, 100-byte MPLS Echos to X.X.X.X/32,
timeout is 2 seconds, send interval is 0 msec:

Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0

Type Ctrl-C to abort.
FFFFF
Success rate is 0 percent (0/5)
Total Time Elapsed 13 ms

but the LFIB of the router from which we make the ping has been populated.

 

R1# show mpls switching X.X.X.X/32

Legend:
(P)=Protected, (F)=FRR active, (*)=more labels in stack.

In-Label Out-Label FEC name Out-Interface Next-Hop
717 117 X.X.X.X/32 Po120 z.z.z.z

a traceroute renders the following output:

R1# trace mpls ipv4 X.X.X.X/32

Tracing MPLS Label Switched Path to X.X.X.X/32, timeout is 2 seconds

Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0

Type Ctrl-C to abort.
0 Z.Z.Z.Z MRU 1580 [Labels: 117 Exp: 0]
L 1 O.O.O.O MRU 1584 [Labels: implicit-null Exp: 0] 190 ms
F 2 Y.Y.Y.Y 2 ms

the Y.Y.Y.Y IP is on the PE_X router.  the PE_X router is a nexus 7K.

and here is the LDP binding 

PE_X# show mpls ldp bindings  X.X.X.X/32

lib entry: X.X.X.X/32, rev 140
local binding: label: imp-null
remote binding: lsr: P.P.P.P:0, label: 117
remote binding: lsr: V.V.V.V:0, label: 95

Does anybody have any idea why?

cheers,

David

 

2 Replies 2

Nagendra Kumar Nainar
Cisco Employee
Cisco Employee

Hi,

It appears that the Initiator is receiving an error from responder (PE_X in your case) as "No FEC mapping" (return code 10). 

Can you try the ping with fec-type as generic?.

 

Thanks,

Nagendra

Hi Nyami,
It seems your LSP path is broken in between , please check if any interface has broken LDP.
You need to check it hop by hop.

Thanks,