[Info-vax] TCPIP performance for VMS

[Jim]

On Apr 22, 3:51 am, JF Mezei <jfmezei.spam... at vaxination.ca> wrote:
> Found out that my old MAC can sustain outbound FTP transfers at roughly
> 80KB/s (640kbps on an 800kbps ATM/PPPoE link (ADSL).
>
> The Alpha VMS host, sitting next to the mac at the ethernet levl only
> does 49 KB/s ( 392 kbps) sending data to the same FTP host on the internet.
>
> going towww.speedguide.net:8080gives me some of the TCP parameters.
> (you can curlhttp://www.speedguide.net:8080on VMS and then copy the
> url in the results (a redirect done with evil javascript) and paste it
> in a browser to see the results).
>
> while pmtu_enable is set to 1 on the VMS host, speedguide reporrs MTU
> discovery is set to off.
>
> Setting ipmtu to 1492 (ADSL MTUs) with ifconfig make no difference to
> the FTP performance on the VMS host.
>
> I tried changing tcp_rexmit_interval_min to different values, and it
> just seemed to decrease performance when the manual says it should
> increase it for high latency links.
>
> The TCPIP stack also doesn't seem to support timespamps in the TCTP
> header. Anyone know if this can be enabled ? (this is used by modern
> stacks to configure their congestion management).
>
> Has anyone ever dealt with this ?
>
> Is the answer: Migrate to Multinet ?

I'm not a user of HP's TCP so I don't have answers to the questions
that you ask - but I will offer this - the TCP send indow size can
impact the speed of FTP transfers. Your MAC is faster than the VMS
system when sending a file - does it use the same send window size as
the VMS system? If not, try setting your VMS system to match it and
see if you get similar performance.