Traceroute problem

[rumon8401]

Why traceroute is missing first one? Can't understand. Can any one tell me the reason. ping is also ok.

traceroute vrf SERVICE-MGMT 10.10.10.1
Type escape sequence to abort.
Tracing the route to 10.10.10.1
VRF info: (vrf in name/id, vrf out name/id)
  1  *  *  *
  2 113.128.220.9 [MPLS: Label 16067 Exp 0] 1 msec 1 msec 1 msec
  3 113.128.220.234 2 msec 1 msec 1 msec

[Nagendra Kumar Nainar]

Hi,

113.128.220.9 is your egress PE?. Are you getting just the egress PE and remote CE or you are getting all the hop details?.

Can you share the topology details as well.

-Nagendra

[rumon8401]

I am issuing traceroute from PE router. its missing my first P routers hop.

[Nagendra Kumar Nainar · Accepted solution]

What is your P router?. Do you just ahve 1 P router connecting Ingress and egress PE?.

Normally when a P router receives a TTL expired MPLS packet, it generate ICMP message with source as self, destination as source of the TTL expired packet and use the same label from the TTL expired packet. This way the error message will be delivered from P router to remote/egress PE and back to Ingress PE and then to source.

In your case, I think "no mpls ip propagate-ttl" is not configured on ingress PE. If it is, I think you wont see the *** as the TTL of top label will be set to 255. 

[rumon8401]

Hi,

Thanks for your help. After execute "no mpls ip propagate-ttl" in PE router the problem is solved. But another ip got below problem. please help me.

traceroute vrf SERVICE-MGMT 10.10.10.111 numeric
Type escape sequence to abort.
Tracing the route to 10.10.10.111
VRF info: (vrf in name/id, vrf out name/id)
  1 103.128.220.233 [MPLS: Label 16068 Exp 0] 2 msec 1 msec 1 msec
  2 103.128.220.234 2 msec 1 msec 1 msec
  3  *  *  *
  4  *  *  *
  5  *  *  *
  6  *  *  *
  7  *  *  *

[Nagendra Kumar Nainar]

The failure appears to happen beyond the CE router. Do you have a return path for the router address from where you trigger the trace?. 

Can you try specifying different source address from same VRF and see if it helps?.

-Nagendra

[rumon8401]

The destination address is a AAA server address its under vrf SERVICE-SERVER.

ping and service is ok but trace got error.