[c-nsp] TTL not decrementing (MPLS, SXI, Sup720)

[Tim Durack]

On Wed, Mar 9, 2011 at 3:20 PM, Tim Durack <tdurack at gmail.com> wrote:
>
> On Wed, Jan 26, 2011 at 3:51 PM, Peter Rathlev <peter at rathlev.dk> wrote:
>>
>> On Wed, 2011-01-26 at 20:01 +0000, Phil Mayers wrote:
>> > There are some funny behaviours w.r.t traceroute under PFC-3B and
>> > earlier versions. Do you have a mix of PFC/DFC versions?
>>
>> Thanks for the tip. I looked more carefully at other devices and found
>> out that at least one other device behaves like this. And it's also
>> PFC3B with traffic exiting a CFC-equipped 6724-SFP, like this device.
>>
>> Other devices with PFC3C (i.e. VS-S720-10G) but similar CFC-equipped
>> cards haven't got the problem. And PFC3B-equipped cards where the
>> traffic arrives on DFC3C-equipped cards (WS-X6708-10GE) also haven't.
>>
>> > We see oddities routinely with penultimate hop popping and vrf aggregate
>> > labels, including the same behaviour you're seeing. I believe it's a
>> > hardware limitation.
>
> I think I'm seeing something similar with a few 6504/SUP720-3BXL/6724-CFC
> running 12.2(33)SXI3.
> Traceroutes crossing these units in the global table timeout. Works fine in
> a VRF.
> Can't mpls ping/traceroute from these units in the global table. Works fine
> in a VRF.
> This makes troubleshooting unnecessarily difficult. Anyone found Cisco
> documentation explaining this behavior?
> --
> Tim:>
>

For the record, my problems were self-inflicted. CoPP configured with
a default deny. Had missed an important class: mpls ping/traceroute
uses udp 3503, not icmp. Added class, problem solved.

-- 
Tim:>