[c-nsp] traceroute shows mpls labels...how?

[Phil Bedard]

Just the probe packets differ in protocol the responses are always ICMP responses.  

Phil

Sent from my iPad

On Aug 22, 2012, at 4:03 PM, Chris Evans <chrisccnpspam2 at gmail.com> wrote:

> Also this depends on vendor too.  IIRC junos uses udp for its trace routing and ios uses icmp.    Meaning that if you did traceroute from a cisco box going over a juniper network the labels wouldn't show and vice versa.   You brought up something I was 100% suee about a few years ago but those brain cells are gone.  
> 
> On Aug 22, 2012 2:58 PM, "Phil Bedard" <philxor at gmail.com> wrote:
> There are ICMP extensions to carry MPLS label stack information but the trace route application needs to support it.   The windows client doesn't.
> 
> Phil
> 
> Sent from my iPad
> 
> On Aug 22, 2012, at 3:21 PM, "Aaron" <aaron1 at gvtc.com> wrote:
> 
> > Do you all know how this works?  How is traceroute able to report back the
> > mpls label that is in use in the transit hops?  Also wondering why I don't
> > see this on windows command line tracert
> >
> >
> >
> > Aaron
> >
> >
> >
> >
> >
> > RP/0/RSP0/CPU0:9k#trace vrf one 1.2.3.4 source 2.4.6.8
> >
> >
> >
> > 1  19.1911.5 [MPLS: Labels 16001/16220 Exp 0] 2 msec  1 msec  0 msec
> >
> > 2  19.1911.1 [MPLS: Label 16220 Exp 0] 0 msec  0 msec  1 msec
> >
> > 3  88.88.191.22 0 msec  0 msec
> >
> >    19.1911.33 1 msec
> >
> > 4  88.88.191.18 1 msec  1 msec  0 msec
> >
> > 5  88.88.135.221 10 msec  10 msec  11 msec
> >
> > 6  122.47.236.130 [MPLS: Label 17039 Exp 1] 47 msec  49 msec  51 msec
> >
> > 7  122.47.154.53 [MPLS: Labels 0/17017 Exp 1] 48 msec  49 msec  47 msec
> >
> > 8  122.45.30.134 [MPLS: Labels 23417/17016 Exp 1] 48 msec  49 msec  47 msec
> >
> > 9  122.45.1.17 [MPLS: Labels 23439/17016 Exp 1] 50 msec  49 msec  51 msec
> >
> > 10 122.45.31.189 [MPLS: Labels 0/17016 Exp 1] 51 msec  54 msec  51 msec
> >
> > 11 122.45.158.34 [MPLS: Labels 0/16009 Exp 1] 49 msec  50 msec  47 msec
> >
> > 12 122.45.104.49 46 msec  46 msec  47 msec
> >
> > 13 122.45.108.14 47 msec  47 msec  47 msec
> >
> > 14  *  *  *
> >
> > 15  *  *  *
> >
> > 16  *
> >
> >
> >
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