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New Member

traceroute - 2 similiar hop ..

hi experts..

does anyone know why traceroute trough MPLS resulting 2 similiar hop as below.

hop1 = home ce

hop2 = home pe

hop3 = remote ce

hop4 = remote ce (this is twice)

hop5 = remote host

furthermore, i can't see remote default gateway for net 10.193.28 /28 which is 10.193.8.46

root@OSS # traceroute 10.193.8.33

traceroute to 10.193.8.33 (10.193.8.33), 30 hops max, 40 byte packets

1 10.196.197.6 (10.196.197.6) 1.008 ms 0.809 ms 0.764 ms

2 10.172.34.9 (10.172.34.9) 3.778 ms 3.716 ms 3.737 ms

3 10.167.1.60 (10.167.1.60) 7.640 ms 7.485 ms 7.508 ms

4 10.167.1.60 (10.167.1.60) 7.554 ms 7.520 ms 7.492 ms

5 10.193.8.33 (10.193.8.33) 7.856 ms 7.508 ms 7.344 ms

6 REPLIES
Silver

Re: traceroute - 2 similiar hop ..

Hi,

IOS release? platform?

Regards

Andrea

New Member

Re: traceroute - 2 similiar hop ..

it is 12.2

7609 series

Silver

Re: traceroute - 2 similiar hop ..

Please past a 'show ver'

Thanks

Andrea

Cisco Employee

Re: traceroute - 2 similiar hop ..

Daniel,

You seem to be running into CSCef16357, which is caused by an ASIC limitation on the Sup720. This should only happen when "no tag ip propagate-ttl" is configured on the ingress PE (home PE in your scenario).

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=cscef16357

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: traceroute - 2 similiar hop ..

Hi!

We also see that behavior with sup720-3bxl. Whenever such a switch does PHP it also decreases the ttl of the resulting packet (what it shouldn't). If this is an IP-Packet the switch sends a packet with ip ttl=0(!).

Is there any workaround? Besides replacing the sup720? This seems to me like a show-stopper for the sup720 in an MPLS enviroment. Any HW upgrades that solve this issue planned?

Christoph

New Member

Re: traceroute - 2 similiar hop ..

This is a last device whee the label is taken out and packet is delivered to the rempte host ,without loosing its integrety...

Here if you see the show label command you will find that on this interface( outgoing interface ) it has two hops.

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