Uh ???
The TCP window size is present in every single TCP packet.
As such you should be able to extract the value and plot it.
However, I dont know if Ethereal can do it
The receiving station will sent the windowsize telling how much data the
transmitting station can send with out waiting for an acknowledge.
Typical 16K byte
It will decrease the window size in face of packet loss to adjust the
sender to the available bandwith.
Normally you dont need to worry about this
It will also decrease if the reciever runs out of buffer space.
In this case, you should rather fix the problem than monitor.
No need to plot a graph if you see this behgaviour - use more CPU power
and more memory in the server.
The initial value can vary from machine to machine, and it also depends
on wether you use "slow start"
In "slow start" the server starts up with a fairly small window and
increases the size until packets starts getting dropped. This is the
best behaviour seen from the network.
Without "slow start" the server will start out with maximum windowsize
which will give the user the best performance but can load the network
for a short period.
Regards
Jens Elmo
-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx
[mailto:ethereal-users-bounces@xxxxxxxxxxxx] On Behalf Of ronnie
sahlberg
Sent: 15. november 2005 09:43
To: Ethereal user support
Subject: [Ethereal-users] Re: Plotting TCP Congetion Window evolution
No,
it is not possible using any tool.
the congestion window is an artificial limit imposed internally by the
TCP sender.
its size is not stored inside the packet.
neither is it possible to determine it by looking at a trace.
different implementations also use different/tweaked methods how they
manage the congestion window internally making it more difficult.
you really need to know the exact algorithms in great detail about the
exact specific implementation of the host sending the data in order to
be able to "guess" what the congestion window is set at at a specific
point in time.
On 11/15/05, Prasad Kularatne <kularatn@xxxxxxxxxx> wrote:
> Hi folks,
>
> Does anybody know whether it is possible to plot the TCP Congestion
> Window evolution using Ethereal?
>
> Please advise. Thanks.
>
> Good Luck!
> Prasad
>
>
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