<hunter.zhough@gmail.com> wrote in message
news:1129910259.550381.218250@g49g2000cwa.googlegr oups.com...
> Hi Tim,
>
> Thank you for your valuable response. I am trying these tuneable
> parameters.
>
> While these parameters should be able to change via AIX no command, I
> don't know how to change the item 4 for Retires and Timeout, and 5
> "Receives before ACK".
>
> Could you please help to advice which parameters may reflect those in
> the item 4 and 5?
>
> Here is the TCP tuneable parameters:
>
>
http://publib.boulder.ibm.com/infoce...ixcmds4/no.htm

OK, please consider any "compatibility mode" setting etc. for V5.2, see:
http://publib.boulder.ibm.com/infoce...htm#migrcompat
and/or "enhancements" in V5.2, see:
http://publib.boulder.ibm.com/infoce....htm#noandnfso

4) reducing the low-level "Retries" (say, to 3) and "Timeout" values (to 2 x
estimated propagation time, plus latency/turn-around) for high-reliability
links/connections.

"Retries" appears to default to 3 as "ndp_umaxtries" (TCP being built on top
of UDP unicasts between the server & client). The timeouts are dynamically
learned it would seem, but there are a lot of parameters in there and I may
have missed it.

The related high-level (TCP connection-related) values are set/changed via
the rto_min=, rto_max= and rto_limit= values, it would seem.

5) increasing the low-level "Receives before ACK", if implemented as a
separate, tuneable parameter (other than by "Receive Window").

This appears to be two parameters: a) delayacks=1 or 3 on the "client side"
and b) delayackports=21 on the "client side" (20-control and 21-data for
FTP, by default, on the "server side"). This will only send an ACK to the
server when requested by a SYN request from the server (has reached its max
send window) or a FIN (end-of-transfer).

Additionally, review the sack= , tcp_init_window= , rfc1323= and rfc2414=
values and their meanings and inter-relationships.

I think that covers the points adequately for now.

HTTH
--
Regards,
Tim Clarke (a.k.a. WBST)