[106014] in North American Network Operators' Group
RE: Analyzing traces for performance bottlenecks
daemon@ATHENA.MIT.EDU (Tim Sanderson)
Thu Jul 17 13:00:56 2008
From: Tim Sanderson <tims@donet.com>
To: "nanog@nanog.org" <nanog@nanog.org>
Date: Thu, 17 Jul 2008 13:00:26 -0400
In-Reply-To: <4551EAB41622EC4AA6CFAAB005485C017F1DF5@SFPWMF107.polk.com>
Errors-To: nanog-bounces@nanog.org
What about gnuplot? Maybe it provides something more than xplot?
http://www.gnuplot.info/
--
Tim Sanderson, network administrator
tims@donet.com
-----Original Message-----
From: Bulger, Tim [mailto:Tim_Bulger@polk.com]
Sent: Thursday, July 17, 2008 12:14 PM
To: Sam Stickland; Matt Cable
Cc: nanog@nanog.org
Subject: RE: Analysing traces for performance bottlenecks
There is a Java version of xplot available now called jPlot. It works in l=
argely the same way.
http://www.tcptrace.org/jPlot/
Regards,
Tim
-----Original Message-----
From: Sam Stickland [mailto:sam_mailinglists@spacething.org]
Sent: Thursday, July 17, 2008 11:53 AM
To: Matt Cable
Cc: nanog@nanog.org
Subject: Re: Analysing traces for performance bottlenecks
Matt Cable wrote:
> Kevin Oberman <oberman <at> es.net> writes
>> tcptrace is old and pretty basic, but it can provide a LOT if
>> information. Combined with xplot, the graphs often point to the exact
>> nature of a TCP problem, but you need a really good understanding of
TCP
>> to figure anything out.
>>
>
> Wireshark also provides tcptrace-like graphs ("Statistics -> TCP
Stream Graph ->
> Time Sequence Graph (tcptrace)"). They're not quite as pretty, but
are just as
> effective at tracking down all sorts of TCP problems, provided, as
Kevin said,
> you have a really good understanding of how TCP behaves
Thanks for all the replies so far. While the TCP graphs are useful they are=
very difficult to read in Wireshark - they really need to be displayed in =
xplot, but this requires an X11 setup?
I've found NDT:
http://e2epi.internet2.edu/ndt/
This uses a java applet hosted on a web100 patched linux server to record n=
etwork diagnostics from connecting clients. A typical report might look lik=
e this:
Web100 reports the Round trip time =3D 122.15 msec; the Packet size =3D=
1260 Bytes; and
No packet loss was observed.
C2S throughput test: Packet queuing detected: 1.09%
S2C throughput test: Packet queuing detected: 1.32%
This connection is receiver limited 84.33% of the time.
Increasing the the client's receive buffer (63.0 KB) will improve per=
formance
This connection is sender limited 1.70% of the time.
Increasing the NDT server's send buffer (127.0 KB) will improve perfo=
rmance
This connection is network limited 13.96% of the time.
The theoretical network limit is 7869.69 Mbps
The NDT server has a 127.0 KByte buffer which limits the throughput to =
16.37 Mbps
Your PC/Workstation has a 63.0 KByte buffer which limits the throughput=
to 4.09 Mbps
The network based flow control limits the throughput to 8.73 Mbps
Client Data reports link is 'OC-48', Client Acks report link is 'OC-12'
Server Data reports link is 'OC-48', Server Acks report link is 'T3'
Something that could provide a similar, automated analysis of a TCP stream =
capture is what I'm after, although I doubt a standard packet capture will =
be able to provided as many metric as web100 stack can.
Sam
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