Traceroute

vicky.dhas · ‎03-25-2010

Hi friends ,

can any of you explain the trace route o/p here . iwant to know the number of hop and total latency took to reach the destination i was tracing.

Tracing the route to 192.168.231.13

1 *

172.31.12.177 [MPLS: Label 1151 Exp 0] 36 msec *

2 172.31.1.66 [MPLS: Label 4929 Exp 0] 32 msec

172.31.2.46 [MPLS: Label 4391 Exp 0] 36 msec

172.31.1.66 [MPLS: Label 4929 Exp 0] 32 msec

3 172.31.42.194 [MPLS: Label 22311 Exp 0] 40 msec

172.31.1.218 [MPLS: Label 22311 Exp 0] 36 msec

172.31.42.194 [MPLS: Label 22311 Exp 0] 40 msec

4 172.31.2.5 [MPLS: Label 1274 Exp 0] 40 msec 36 msec 36 msec

5 59.163.55.133 40 msec * 36 msec

thanks

Ganesh Hariharan · ‎03-26-2010

Hi friends ,

can any of you explain the trace route o/p here . iwant to know the number of hop and total latency took to reach the destination i was tracing.

Tracing the route to 192.168.231.13

1 *

172.31.12.177 [MPLS: Label 1151 Exp 0] 36 msec *

2 172.31.1.66 [MPLS: Label 4929 Exp 0] 32 msec

172.31.2.46 [MPLS: Label 4391 Exp 0] 36 msec

172.31.1.66 [MPLS: Label 4929 Exp 0] 32 msec

3 172.31.42.194 [MPLS: Label 22311 Exp 0] 40 msec

172.31.1.218 [MPLS: Label 22311 Exp 0] 36 msec

172.31.42.194 [MPLS: Label 22311 Exp 0] 40 msec

4 172.31.2.5 [MPLS: Label 1274 Exp 0] 40 msec 36 msec 36 msec

5 59.163.55.133 40 msec * 36 msec

thanks

Hi,

Check out the below link on studying the output for traceroute commnd hope to help !!

http://www.exit109.com/~jeremy/news/providers/traceroute.html#reading

Ganesh.H

Giuseppe Larosa · ‎03-26-2010

Hello Vicky,

the destination is 5 hops away.

at hops 1,2,3 there are two different path options

at hop 1 one of the two next-hops has probably no ip unreachables configured (or some commands related to MPLS ) and does not provide an answer

you get a round-trip-time delay information (two way). latency is single way.

Hope to help

Giuseppe

vicky.dhas · ‎03-26-2010

Many thanks Giuseppe

regards

rajivrajan1 · ‎03-30-2010

hi,

can anyone explain what is EXP 0 / EXP in traceroute o/p , when it is crossing mpls networks?

thnx in advance.

Rajeev.S

Giuseppe Larosa · ‎03-30-2010

Hello Rajeev,

MPLS header has a 3 bits wide EXP field that can be used for QoS purposes, so the output reports the value of EXP field in MPLS header.

standard behaviour is that EXP bits are a copy of IP precedence bits of the IP packet carried inside the MPLS frame.

to be noted multiple MPLS labels (label stack) can be in use but the show refers to the most external label.

the MPLS header contains also a TTL 1 byte field that can be a copy of IP packet TTL byte or not.

This means that MPLS hops can be hidden in a traceroute started by a customer depending on the settings of mpls propagate-ttl

Hope to help

Giuseppe

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