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

[Aaron]

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  *