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slow transfer over TR

gary.post@amd.com writes:
 > I have four computers with 3c319 cards in a test network - they are
 > connected together with a 3com SuperStack II Hub TR (no management
 > module) - I can ftp a 39M file from any computer to any other but can
 > only get 200-250Kbytes of transfer speed - the hub says I have the 16M
 > rate enabled and it never wavers - there is an error light about every
 > 10-20 seconds (random) - I am expecting a greater transfer rate, should
 > I be getting a better rate, or am I missing something

I would say that, for that version of the driver, 250KB/sec isn't out
of line with what I've seen on my network. The 2.1.x (x>=50) driver
does have some enhancements that affect transfer rate. Namely the
receive buffer size has increased and the IP checksum is computed when
the frame is copied from the receive buffer. On my network at home (8
bit IBM 16/4 adapters, Ancient Proteon MAU) using ttcp during a full
moon and a nice tailwind I've achieved transfer rates up to 700KB/sec,
and I heard a report of 1MB/sec transfer rate from another tester. By
my calculations 1MB/Sec is about 50% ring utilization. But you know
what they say about benchmarks - there are lies, damned lies and
benchmarks. Your mileage may, and probably will, vary. :-)  

That patch has been ported back to 2.0.30 if you're interested:


I'm interested in hearing what transfer rates other people get. 

 > computer 1 is sitting idle, zero network traffic to or from it
 > computer 2 is only getting the file, no other tasks running on it
 > computer 3 is also doing nothing but supplying the 39M file for
 > transfer, idle when not transferring
 > computer 4 is running X with nearly zero cpu idle time, no network
 > traffic generated from it
 > it is not like I have loaded the network or the computers down yet
 > all computers have a fresh Infomagic (April 97) kernel 2.0.29 install -
 > ibmtr.c 49,699 bytes 29aug96 compiled and loaded as a module - running a
 > K6 at 150M with 32M ram in each computer - have tried a couple different
 > brands of motherboards with same results
 > do I have to set up a master server - it would seem to me that the hub
 > is taking care of passing out the tokens - can someone point me to a
 > source of web reading that explains setting up a reliable TR network
 > I would be interested in a pointer to some diagnostic software that
 > could enlighten me as to what is happening - the only sniffers that I
 > have run across have been for stealing passwords out of network traffic
 > and serve no other useful purpose - I am looking for something/someone
 > that can give me a micro-second by micro-second account as to what is on
 > the 'wire' - not what byte contains what, but time between packets, how
 > long a packet is (time), minimum time between packets from the same
 > source and so on

Sounds like you need tcpdump. There is a patch for tcpdump 3.3 for
token-ring in my ftp directory as well. 

 > thanks y'all
 > gary post