ISC 2.2 SL/IP throughput?

[Conor P. Cahill]

In article <1990Aug23.160013.1199 at scuzzy.mbx.sub.org> src at scuzzy.mbx.sub.org (Heiko Blume) writes:
>
>can someone tell me what throughput i can expect with sl/ip over
>a modem connection with HST modems (14400bps)? we talk to the modems
>at 19200 and use hardware flow control (FAS with 16550 chips). we did
>a ftp and the throughput was ~0.2 KB/s on a 600KB file, which is unacceptable.
>did we do something wrong? (of course we did sldialup/attach 19200 ttyF01).

Your problem is probably caused by the fact that the HST modems running at 
14.4kbs are not truely full duplex.  They (in a similar vain to the t2500) have
a high speed channel in one direction and a low speed reverse channel 
(switching the directions as necessary).  

This is a really bad scenario for packetized protocols that require
acknowledgment packets (unless the modem "spoofs" the protocol, like what
the Telebits do to UUCP).

Your best bet would be to get a v.32 modem (if you require the HST 14.4 
compatibility for other purposes, use an HST dual-standard).

Full duplex 9600 baud modems (i.e. v.32) should get around 800 bytes/sec
throughput on clear lines.


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Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
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