Help Interpreting traceroute output

trlists at clayst.com trlists at clayst.com
Mon Oct 18 23:37:01 EDT 2004


On 18 Oct 2004 dsr at tao.merseine.nu wrote:

> Suppose that your app occasionally sends data that is just larger than
> one packet-payload, requiring a second packet. And suppose that
> there is a router somewhere in the middle which always drops
> that second packet. But a single packet from traceroute always
> gets through...

OK, I see your point!  Now how would you figure that out?  I presume by 
looking at a packet-level log.

> httperf is a good tool for testing HTTP connectivity and
> performance.
> www.hpl.hp.com/personal/David_Mosberger/httperf.html

Thanks.  I looked at the docs and it looks like it might provide some 
useful results.  However to be most useful I really ought to run it 
from the mirror, which is POSTing the files to our server.  If we are 
trying to model the real-life issue carefully then initiating the 
connections from our end will only provide partial info, at best.

> But your best bet is to talk to your ISP and their upstream (if
> any) and see what they say.

Well in this case my client is the ISP (a hosting provider) and the 
upstream is multiple OC3 and DS3 connections to 3 different backbone 
providers.  Performance generally is not a problem during our attempts -
- the only problem is this one specific operation. So it has to be 
something in the installer, at the mirror, or a routing problem from us 
to the mirror or back.

Thanks for all the assistance ...

--
Tom






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