From owner-freebsd-questions  Fri Feb 18  8: 6:56 2000
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To: "eric ." <anon025@hotmail.com>
Cc: freebsd-questions@FreeBSD.ORG
Subject: Re: routing table. deleting broadcast 
In-reply-to: Your message of "Fri, 18 Feb 2000 03:12:47 GMT."
             <20000218031247.65230.qmail@hotmail.com> 
Date: Fri, 18 Feb 2000 08:06:44 -0800
From: "Kevin Oberman" <oberman@es.net>
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A longer cable is very unlikely to help. The 802.3 spec for UTP allows
for any length of cable up to 100 meters, but there is no minimum. I
have seen reports that some NICs get unhappy with VERY short cables,
but there are cables less than 2 feet long, so that should not be your
problem.

You talk about "too many collisions", but I have no idea what this
means. If you are running half-duplex, collisions are normal and may
run near 100% with normal operations and standard protocols with no
noticeable slow-down.

The most common cause of this sort of problem is mis-matched duplex
options with one end running full duplex and one running half
duplex. The end running full-duplex will not bother to check for
carrier or collisions and many frames will be trashed. the half duplex
end will see MANY collisions and get errors as well. The errors will
include late collisions, framing errors, and CRC errors. Except for
the late collisions, the errors will show up at either end.

The presence or absence of the broadcasts should be immaterial, but,
if the duplex is not consistent, removing them might well make things
run better.

For most interfaces, the ifconfig command should tell you how the port
is running (in the 'media' line) and auto-configuration of the
duplexing is known to fail with some NICs.

Here is an example of the ifconfig output:
> ifconfig xl0
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 24.15.220.1 netmask 0xfffffc00 broadcast 24.15.223.255
        ether 00:50:da:80:4b:43
        media: 10baseT/UTP <half-duplex>
        supported media: autoselect 100baseTX <full-duplex> 100baseTX <half-duplex> 100baseTX 10baseT/UTP <full-duplex> 10baseT/UTP <half-duplex> 10baseT/UTP

R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman@es.net			Phone: +1 510 486-8634


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