Subject: Tuning Parameters for TCP/IP link over Satellite in AIX 4.2.1 ?

From: Pedro Sanchez <[email-masked]>
Date: Thu, 29 Oct 1998 19:38:04 +0100

Hello everybody !!!

I am a young engineer working in a project about telehealth care  and I
need to improve times on sending images using
geostationary satellite links  .

We need roughly a speed about 128kbps (or better).

Currently we are using 4 ISDN channels (512K) and it  would be good to
know if we can get this speed anyway.

Our software runs  on two IBM/RS6000  machines and operating system is
AIX 4.2.1 .

VideoConference will be running inside the application (project)  too.

Sockets are implemented in the application and possibly changes in the
system will be needed too, I don't know !!!

I know the "no" command for network parameters adjustment,   Do I need
to modify them?
I found information on :
  - rfc1323.
  - max congestion window size.
  - buffer size.
  - tcp windows size.
  - etc ...

 However I don't know how to set the best tunning with them.

thanks & regards..

- Pedro Sanchez Garcia . (IBERMATICA).

---

From: "Shvodian, W. M. (Bill)" <[email-masked]>
Date: Thu, 29 Oct 1998 14:52:19 -0500

Pedro, If you don't already have one, a good start would be to get a
copy of the AIX Performance Tuning Guide from your local IBM sales rep.
It covers tuning the parameters you mentioned below for general network
performance improvement.  You definitely want to turn rfc1323 on (I
believe the default is off.)  You will also want to increase
tcp_sendspace, tcp_recvspace, sb_max, xmt_que_size and rec_que_size.

Bill

> -----Original Message-----
> From:	Pedro Sanchez [SMTP:[email-masked]]
> Sent:	Thursday, October 29, 1998 1:38 PM
> To:	[email-masked]
> Subject:	Tuning Parameters for TCP/IP link over Satellite in AIX
> 4.2.1 ?
> 
> Hello everybody !!!
>