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

[Manu Chao]

If IP TTL propagation is disabled in your MPLS Core with the no mpls ip
propagate-ttl command in global configuration mode, the TTL value is not
copied in the IP header and on your end to end traceroute.

R/
Manu

On Wed, Jan 26, 2011 at 9:51 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 guess we have to live with it then. At least the PFC3B based sups are
> getting close to a well earned pension.
>
> If anyone would happen to know a work-around, even at the cost of
> performance, I'd really like to hear about it. It's more than enough
> trouble to explain traceroutes without this... :-)
>
> --
> Peter
>
>
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