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

[Aaron]

Chris/Phil, thanks a lot

 

Aaron

 

From: Phil Bedard [mailto:philxor at gmail.com] 
Sent: Wednesday, August 22, 2012 3:29 PM
To: Chris Evans
Cc: &lt,cisco-nsp at puck.nether.net&gt,; Aaron
Subject: Re: [c-nsp] traceroute shows mpls labels...how?

 

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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