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Date:      Sun, 31 Jan 1999 11:02:25 +1030
From:      Greg Lehey <grog@lemis.com>
To:        FreeBSD Questions <questions@FreeBSD.ORG>
Subject:   Excessive collisions on Ethernet
Message-ID:  <19990131110224.I8473@freebie.lemis.com>

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In the last few days I've noticed a really high number of collisions
on my Ethernet.  There are only 5 machines on the network, 3 of which
are barely active, yet I see:

(allegro, running 2.2.6-STABLE)
ed0   1500  <Link>      00.00.c0.44.a5.68 43729816    45 43861788    12 977828
ed0   1500  widecast      allegro         43729816    45 43861788    12 977828

(freebie, running 4.0-CURRENT)
Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs  Coll
ed2   1500  <Link>      00.80.48.e6.a0.61 11976144    12 13389307     0 988340
ed2   1500  widecast      freebie         11976144    12 13389307     0 988340

(panic, running 3.0-CURRENT)
ep0   1500  <Link>      00.a0.24.37.0c.bd      267     0      286     1     0
ep0   1500  widecast      panic                267     0      286     1     0

(papillon, running an old 3.0-CURRENT)
zp0   1500  <Link>      00.60.97.40.fb.e1   734161    11   544548    60     0
zp0   1500  widecast      papillon          734161    11   544548    60     0

(yana, running 2.2.6-RELEASE)
ed0   1500  <Link>      00.00.b4.33.6d.a2     8097    19     5948     0    43
ed0   1500  widecast      yana                8097    19     5948     0    43

The low values for panic and yana are because of a power fail last
night: these two machines aren't on a UPS.

I tried an ftp from panic, copying a file of 45 MB from freebie.  The
transfer ran at about 1 MB/s with about 450 collisions per second on
the freebie side, none on the panic side.  Here are the values before
and after:

freebie:

          Ipkts Ierrs    Opkts Oerrs  Coll
before 11978350    13 13392678     0  989089
after  11994616    13 13424921     0 1009912
diff	  16266     0    32243     0   20823

panic:
          Ipkts Ierrs    Opkts Oerrs  Coll
before      480     0      651     1     0
after     32143     0    16679     1     0
diff	  31663     0    16028     0     0

Looking at these results (40% collision rate on freebie), it would
seem that something is seriously wrong in the network.  On the other
hand, allegro also shows a large number of collisions.  At the moment
I'm suspecting the (3 month old) Ethernet board in freebie, but I was
wondering if there were other reasons which might apply.

Greg
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