FDDI EINTR during highspeed transfer ?

From: HSR Sys-Admin <alpha_at_jungle.deceiver.org>
Date: Fri, 28 Feb 1997 16:50:21 +0100 (CET)

Hello,

we have an AS 2100 5/250 1 GB 3.2c with fddi as the server sending
and an AS 600 5/333 256 MB 3.2g with fddi as the client receiving data

both machines are connectet directly with fddi (both at fta0).

we wrote two C-programs with socket open und list, connect and all that
stuff..

in the center there is an loop with (BUFFER=4312 & datastorage=huge MBs)

gotbytes = recv(socket_descriptor , datastorage, BUFFER,0 );

 

with little packages of data smaller than 4 MB there is no problem
with the transfers...


above 4-5 MB with raising probabilty the transfer will fail in the middle
and gotbytes will show up -1 which means: EINTR = interrupted system call.

no data could received.

On our investigation we noticed, the bigger the receiving process is, the
probability of failing is rising!

Also we noticed a difference between 3.2C and 3.2G fddi_config!

on 3.2C the command fddi_config -i fta0 -v 4.00 works ok

on 3.2G the same will produce an error!!! ???

My Questions:

will we need a patch for the fddi?
will we need to update fddi-firmware? (Rev. 2.46 )

monitor net is showing up, that the rate of incoming packets is twice as
 high as outgoing on the receiving machine! Is that normal?

we tried at first the BUFFER=4352 but always noticed: only 4312 bytes were
transportet (gotbytes). Is there an explanation for this behavoiur?

what is the best setting for ipmtu and BUFFER?

shall we use setsockopt and manipulate on SO_RCVBUF ( 32K present 128K max) ?



any help would be great! a summary will be published for sure!



bye

Hendrik Roepcke

PS: we start the C-programms from IDL...


PPS: i once red in the news about FDDIMON, a tool for monitoring FDDI-Lines
     is that available for DU? and where to FTP?
Received on Fri Feb 28 1997 - 18:29:06 NZDT

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