Problems with SLIP on Ultrix 4.0

[Toivo Pedaste]

larryd at bnrmtl.bnr.ca (Larry Dunkelman) writes:


>I have slip running between a 5820 and 3100 running Ultrix 4.0. It has 
>been working fine until today.  All of a sudden, I started to get 
>the following :

>/etc/ping eden
>sendto: no buffer space available
>ping: wrote eden 64 chars, ret=-1
>.
>.
>.


I suppose I'll contribute some of my ignorance on the matter.

When we were running slip across a 2400 baud line this would occur at
times, in that case if you offed the interface for a while it would
eventually go away. On a couple of 9600 baud lines that were connected
directly to a uVax the problem didn't seem to occur, however when we
moved one of these lines onto a Decserver it started happening regularly.

My guess as to what is happening is the the buffer space refered to is
a per interface limit on the number of data buffers outstanding and
the message occurs when the data is being sent faster than it is able
to be transmitted. There is a problem that this condition is not recovered
from, possibly due to a bug in the networking code that doesn't usually show
up because it is generally possible to transmit onto the ethernet faster
than to send data into the network software.

I have query outstanding with Dec support on the matter, since it was Dec that
suggested the slip via decserver configuration would work.
-- 
	Toivo Pedaste				ACSNET:   toivo at uniwa.uwa.oz
	WARCC,					INTERNET: toivo at uniwa.uwa.oz.au
	University of Western Australia		Phone:    (09) 380 2605