Mailinglist Archive: opensuse (3637 mails)

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Re: [SLE] is this bad? almost 30000 colisions
  • From: Alexandr Malusek <Alexandr.Malusek@xxxxxxxxxx>
  • Date: 29 May 2001 11:25:20 +0200
  • Message-id: <8666eko6bj.fsf@xxxxxxxxxxxxxxxxxxxxx>
Raul Gutierrez Segales <oxford@xxxxxxxxxxxxxxxx> writes:

> eth1 Link encap:Ethernet HWaddr 00:E0:7D:93:FA:B7
> ...
> RX packets:1100034 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1190917 errors:5 dropped:0 overruns:0 carrier:4
> collisions:29612 txqueuelen:100

Your collision rate (collision/TX_packets) is 29612/1190917 = 2.5%.
It's quite normal on an Ethernet with a HUB.

I don't remember interval boundaries of (long term) collision rates
exactly (moreover, recommendations may vary), but to give you an idea:

0- 3 % : quite OK
3- 5 % : still OK
5-10 % : the network is heavily loaded or there is a HW problem,
it should be investigated.
> 10 % : usually indicates a HW problem. If it's because of a heavy load
then subdividing the network into separate subnets is
recommended.

The following is from SunSolve INFODOC 12306:

: SYNOPSIS: Sun Ethernet Interface Support Document/FAQ
:
: colls - Reports the number of collisions since the network booted. If
: output colls is greater than 10% of output packets on one system,
: check the network wiring to that system. When output colls is
: consistently greater than 10% - 15% of output packets on the majority
: of systems, it is time to consider subdividing the network into
: separate networks connected by a router or a bridge.


An Ethernet with a switch (not HUB) gives totally different numbers:

eth1 Link encap:Ethernet HWaddr 00:02:B3:15:E5:14
...
RX packets:16796858 errors:2 dropped:0 overruns:2 frame:0
TX packets:16698919 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100

No collisions are quite normal in this case.

--
Alexandr.Malusek@xxxxxxxxxx

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