Help Interpreting traceroute output

dsr at tao.merseine.nu dsr at tao.merseine.nu
Mon Oct 18 13:29:01 EDT 2004


On Mon, Oct 18, 2004 at 12:35:12PM -0400, trlists at clayst.com wrote:
> In doing so I've been using traceroute on several different Linux boxes 
> and the results don't make sense to me.

Remember that traceroute is not a performance measurement tool.
It's a connectivity checker. 

Your measurements will differ from reality because:

- ICMP is not handled the same way as UDP which is not the same
  as TCP 

- your packet size will be different

- your routing is not guaranteed

routers may handle traceroutes and/or pings preferentially, may
artificially restrict them, may route them differently, store
them in different buffers, all sorts of things.

Performance testing is best done between the points in question
with the protocol in question using a payload as similar to
"typical" as possible.


> values showing that a test packet made it to gateway 5 with a TTL of 
> 204 ms and the next one made it to gateway 6 with a TTL of 189 ms 
> (presumably because things were a little faster when the second packet 
> was sent)?

This is correct.


-dsr-



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