Traceroute through MPLS cloud

[LEM]

Traceroute through MPLS cloud.I have a simple demo stand for MP-BG. Here is how it looks:
CE1-PE1-PE2-CE2

We have BGP peering between CE and PE routers and OSPF, MPLS, MP-BGP inside provider cloud.

Both CE routers successfuly exhange routes. CE1 can see CE2 routes and vice versa.

I try to make trace from CE1 (192.168.101./0 ) to CE2 (192.168.102.0/24). Here is an output:

SW1.8 # traceroute 192.168.102.9 from 192.168.101.1
traceroute to 192.168.102.9, 30 hops max
1 172.16.13.3 1 ms 4 ms 13 ms
2 * * *
3 172.16.49.9 1 ms * 10 ms

Why do we have this string in output?
2 * * *

Here is a quoute from user guide:
In this mode, the MPLS TTL is independent of the IP TTL. The MPLS TTL is set to 255 on all packets
originated by the switch and on all packets that enter a pseudowire.

So, we should not see mpls path in trace.

[LEM]

It is vpnv4 scenario, so transit routes shoudn't know route to source. I will chek it with record-route

[Erik_Auerswald]

Hi,

can you tell us which devices can be seen in the trace? Is this the complete trace? Are the IP addresses from the incoming interfaces on PE1 and CE2?

Could it be that PE2 creates an ICMP TTL Exceeded message, but lacks a route to 192.168.102.9?

Can you take packet captures on the involved interfaces? That would allow you to see what really happens.

Erik

[Erik_Auerswald]

I meant to write "192.168.101.1" instead of "192.168.102.9"...

[LEM]

Any ideas?

[LEM]

There is MPLS routing between PE devices, not VPLS.

Is there any way to increase response time timeout? But i don't think it can be a problem, because those devices are in one rack.