ADSM-L

Re: TCP/IP Transaction Controls

2000-05-11 17:22:10
Subject: Re: TCP/IP Transaction Controls
From: "Mr. Lindsay Morris" <lmorris AT OPENMIC DOT COM>
Date: Thu, 11 May 2000 17:22:10 -0400
The TXN.. parameters are not for TCP per se.
We normally (on fast machines) set
TCPwindowsize 64
TCPbuffsize 32
TCPnodelay yes

Also check that your MTU sizes match between client, server, and routers in
between.  1500 is a good number to use for MTU, but if a switch in the middle
uses a smaller MTU, it'll have to break up 1500-byte packets into smaller ones,
to be re-assembled later - terrible throughput results.


Gary Ison wrote:

> Hi folks,
>
>         Anyone have a good handle on how to control the TCP/IP packet sizes
> via TSM?  I have reviewed the guides on the parameters TXNBYTELIMIT,
> TXNGROUPMAX, and SELFTUNETXSIZE but they don't offer much detail.  I haven't
> reviewed the tuning guide for any recommendations yet.
>
> Most of my clients and the OS/390 MVS server (TSM 3.7.2.0) use the default
> sizes for these parameters.  I recently increased one NT client (TSM
> 3.7.1.0) to a byte limit of 25600, the max, and my network folks tell me I'm
> overrunning the clients ability to receive data which causes the client to
> shut down the network connection briefly while the CPU does a catch-up.  The
> network doesn't really shut down - the client system just ceases to receive
> data from the NIC.
>
>         I'm looking for some happy medium to allow the optimal throughput on
> the network.  Any suggestions or ideas would be welcome.
>
>         Thanks for the help.
>
>         Gary L. Ison
>         Governor's Office for Technology
>         101 Cold Harbor Drive
>         Frankfort, Ky.   40601
>         Phone:  (502) 564-8724
>             Fax:  (502) 564-6856
> E-mail: Gary.Ison AT mail.state.ky DOT us <mailto:Gary.Ison AT mail.state.ky 
> DOT us>

--
Mr. Lindsay Morris
Mr. Lindsay Morris
Certified: AIX,ADSM, TSM, HACMP,SP
Gresham Enterprise Storage
lmorris AT openmic DOT com
606-253-8000
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