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From: russo@lanl.gov (Thomas Russo)
Subject: Highly asymmetric slip performance -- HELP!
Message-ID: <RUSSO.93Mar18093313@bogon.lanl.gov>
Sender: news@newshost.lanl.gov
Organization: Theoretical Chemistry and Molecular Modeling Group, LANL, NM
Date: Thu, 18 Mar 1993 16:33:13 GMT
Lines: 56
I've been running slip (compressed) to connect my 386bsd system at
home to my sun at work for a while now, but haven't really exercised
file transfers in the pc->sun direction till last night. Hoo boy is
it messed up. Here's the setup:
PC:
386bsd-0.1 patched with the 2.1 patchkit (but not 84-110)
bpf package (i.e. tcpdump, etc) which used to be on ref, may it rest
in peace
hacked slattach which has command line flag to enable compression
CGD's com-beta-0.2.1 com driver with the COM_BIDIR option
16550 UARTS
ifconfig sl0 pc sun -trailers
Port running at 38400 baud
Modem configured for RTS/CTS handshake, cable wired to do that
properly
SUN: running SunOS 4.1.1 with cslip-2.6 installed, autocomp on.
logged in to a special cslip account, getty setting the port at 38400.
Also set to do RTS/CTS handshake
If I transfer (rcp, ftp, cat, whatever) a file from the sun to the pc
I get a throughput of about 8-10Kbps with a v.32+v.42bis modem
(Telebit Qblazer). Not great, but hey, I mostly transfer compressed
binary files, so I guess v.42bis doesn't buy me much. But try to ftp
in the other direction (or do an rcp, or do cat file|rsh sun 'cat
>junk', or...) I get a throughput of about 2kbps! During the sun->pc
transfers the little receive light on the modem blinks away like mad,
hardly ever stopping, but pc->sun shows very little modem activity, a
brief flicker of the send light, a burst of receives (acks?) and then
quiescence for a while.
I believe this kind of thing also happened when I was using the stock
slip that comes with 386bsd (no compression) but never really tried it
much --- I just noticed that tar cf sun:/dev/rst0 /usr took forever to
dump a very small fraction of the tar archive (like only a few
megabytes overnight!), and then said "oh, I gotta get cslip before I
try this again, this is ridiculous", but I guess it was not a
slip/cslip problem.
Has anyone ever seen that happen to them? Any clue what I could be
doing wrong here? This is mega-frustrating, as I would REALLY like to
back up my system onto the tape drive at work because I have no tape
drive at home, and am running backups off of 1.44MB floppies (ACK!).
10kbps isn't great for that, but hey, it's a lot better than 2kbps or
a bazillion floppies!
Can anyone help? I don't even know where to start.
--
Thomas Russo russo@bogon.lanl.gov
Los Alamos National Lab, T-12, Theoretical Chemistry and Molecular Physics
*Opinions expressed are those of the author alone and do not represent
*positions or policies of Los Alamos National Laboratory or the University
*of California
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