How to Determine TCP Window Size
al...@ibm.net
Can someone explain to me how to determine the window size for a particular TCP
session connection (under AIX). Is it as simple as viewing the output from
a 'netstat' command ? Or do I have to perform an IP trace ?
Thanks.
/Alan
Rudy Chukran
will not tell you anything since netstat only shows system global network parameters.
You will have to resort to IP trace or tcpdump. You can make some
general inferences about the window by looking at the receivers
tcp_recvspace (use no -a). If the program doesn't override this default,
then its socket window is bound by this buffer size. If the program does
override the tcp_recvspace, I don't know how to interrogate it externally.
--
Rudy Chukran | IBM RSCS: CHUKRAN at AUSTIN
IBM RS/6000 Technical Support | internet: chu...@austin.ibm.com
Mail stop 4103,11400 Burnet Rd. |
Austin, Texas 78758 |
LAIX Software Consulting
Looking at "no -a" will show you many TCP options, including the
TCP sendspace and TCP receivespace (which default to 16KB) to see
the buffer size used by default. There are getsockopt() and
setsockopt() calls a program can do to get and set these values, so
simply looking at netstat or no -a won't tell you if a particular
socket program has altered the values of these parameters. Looking
at the th_win field in a transmitted IP packet in an iptrace would
show you the remaining portion of the receive buffer.
Best regards,
Paul Laymon
al...@ibm.net wrote:
>
>
> Can someone explain to me how to determine the window size for a particular TCP
> session connection (under AIX). Is it as simple as viewing the output from
> a 'netstat' command ? Or do I have to perform an IP trace ?
>
> Thanks.
>
> /Alan
Craig Malton
The window size is not specific to one application I believe, but to
the whole system. Try taking a look at the command
no -a
to see the network options
Craig