mike@BRL-TGR.ARPA (07/16/84)
From: Mike Muuss <mike@BRL-TGR.ARPA>
[4.2 BSD network trivia]
"connect: out of buffer space" generally does NOT mean that
the kernel is out of MBUFS (easily checked with "netstat -m"),
but instead usually means that there is a backlog in the queue
destined for your output device and that packets are being
dropped.
The most common case of this is with 1822 IMP interfaces connected
via ECUs, under 2 conditions:
1) ECUs have not been set to "15 retry, no relay flapping" mode
(all retry switches up, rightmost switch in that row DOWN).
2) ECUs are operating on a line with LONG noise bursts. (We have 1
such line that goes through a swamp...). What happens here is that
RFNM messages from the IMP are lost, and it confuses the 1822
link optimization code. (Check this with "netstat -h", look for
persistant RFNM counts > 2 ). I have patches for /sys/netinet/if_imp.c
that can be activated with "options NORFNM" in the config file,
drop me a line if you need it.
Best,
-Mike Muuss
(301)-278-6678
AV 283-6678
FTS 939-6678
ArpaNet: Mike @ BRL
UUCP: ...!{decvax,cbosgd}!brl-bmd!mike
Postal:
Mike Muuss
Leader, Advanced Computer Systems Team
Computer Techniques and Analysis Branch
Systems Engineering and Concepts Analysis Division
U.S. Army Ballistic Research Laboratory
Attn: DRXBR-SECAD (Muuss)
APG, MD 21005