[Info-vax] TCPIP performance for VMS

[JF Mezei]

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 to www.speedguide.net:8080 gives me some of the TCP parameters.
(you can curl http://www.speedguide.net:8080 on 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 ?