From owner-freebsd-questions  Thu Dec  9 16: 2:58 1999
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From: "Juha Saarinen" <juha_saarinen@email.msn.com>
To: "freebsd-questions@FreeBSD. ORG" <freebsd-questions@FreeBSD.ORG>
Subject: TCP Large Windows etc.
Date: Fri, 10 Dec 1999 13:00:10 +1300
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Been poking around with sysctl -a and noticed the following:

net.inet.tcp.rfc1323 = 1
net.inet.tcp.recvspace = 16384
net.inet.tcp.sendspace = 16384
net.inet.tcp.sack = 1
net.inet.tcp.mssdflt = 512

I read that as RFC1323 TCP extensions are enabled, ditto TCP Selective
Acknowledgements (SACKs), both what I want. However, the default Receive and
Send buffer is only 16,384 bytes and is the default Maximum Segment Size
really only 512 bytes?

I know how to change the values with sysctl -w, but I was wondering why
they're set so low. Linux 2.2.x scales TCP windows up to 32KB by default,
with a limit of 256KB max (I think). Does the FreeBSD TCP/IP stack support
window scaling as well?


Cheers,

-- Juha




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