Ethereal-users: RE: RE: [Ethereal-users] Can you help me diagnose aperformanceproblem?
The RWIN value (on the winxp machines) is currently set to 128000 (I've
played with this a lot). It's the same on 2 machines, and still one (the
faster) ACKs every 2 segments, and the other every single segment, which is
what I believe is slowing it down. Anyone know what would cause this
behaviour? Thanks all for getting involved!
Steve
> -----Original Message-----
> From: ethereal-users-bounces@xxxxxxxxxxxx [mailto:ethereal-users-
> bounces@xxxxxxxxxxxx] On Behalf Of Ronnie Sahlberg
> Sent: Friday, 30 July 2004 10:16 PM
> To: Ethereal user support
> Cc: 'Ethereal user support'; ethereal-users-bounces@xxxxxxxxxxxx
> Subject: Re: RE: [Ethereal-users] Can you help me diagnose
> aperformanceproblem?
>
> >From: bleonhardt
> >Subject: RE: RE: [Ethereal-users] Can you help me diagnose a
> performanceproblem?
> >
> >tcp uses windowing, so not every packet should be acknowledged - of
> >course, a ACK of every packet / frame will slow down the connection as
> >there's more traffic on the network than usual ..
> rfc2582->rfc1122->rfc813 tells it all
>
> a tcp should ACK (pick first that matches)
> * evey segment with PSH bit set
> * immediately repeat prevoius ack for segments outside the window
> (duplicate
> ack, keepalives and zerowindow probes)
> * every second full size segment upon receival
> * other segments within a reasonable time but may collapse acking of
> multiple acks into a single ack
>
> >.. maybe a resize of the window-size could help .. try DrTCP ( just
> google
> >for it ) to change the settings .. then restart your network ( 2k/xp ) or
> >restart the pc/notebook.
>
> use ping to measure end-to-end latency in seconds. call it RTT. (unit is
> seconds)
> pick out of the air what throughput you want to sustain in Bytes/second.
> call this TP and unit is Bytes/second
>
> RequiredWindowSize is then ::= TP * RTT
>
> set tcp window size to twice this value (to have some safety margin)
>
>
>
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