SUMMARY: Monitoring ethernet load

From: Henrik Schmiediche (henrik@PICARD.TAMU.EDU)
Date: Mon Jul 25 1994 - 16:35:38 CDT

thanks to all who responded to my query concering measurin the
Ethernet load on a system. Here is a quick summary:

  1) There is a sunview program called traffic (comes with SunOS)
     Since I do not Sunview I can't run it. Anyone know who to run
     Sunview programs on plan vanilla X11R5 (or X11R6)?

  2) Anonymous ftp from
       Ethernman - monitor packet traffic on local net.
       Interman - like Etherman but groups by network. IP only
       Packetman - capture and anyalyze packets.

     Great package - just a little overkill if all yopu want to
     know is the load on the system. It is quite a resource hog so
     letting it run for several days to determine the maximum
     load is a little problematic - but it is still a great set
     of programs and I strongly recommend that everytone who needs
     to monitor a network get it.

  3) Get XEnetload.tar.Z from which will give
     you an ethernet load averal like "xload" does.

Here are some miscellaneous comments:

If you have SunOS 4.x, /bin/traffic (run rpc.statd first). I can tell
you that with 40% sustained with peaks approaching 100% the net is
unbearable for diskless or low-memory machines (we've had that for
quite sometime before extra memory and discs arrived).

The recommendation I received was 30-35% load average meant it was time
to segment. I was also asked about busts for short periods but received no
advise. So I am looking for clear answers still.

We have Etherman up most of the time. It gives us graphical information
on who is working hard and may benefit from specialize tuning.

It depends on if you want "freeware" or 3rd party apps. We use a
product here called NetMetrix, HP owns it now. Its gui-based and can
give you all kinds of network stats, like load, who's causing the
load, etc. It also has an option for a regular sniffer-type setup, and
other net high level monitoring products.

As far as load, the rule of thumb that I use is when a segment hits
10% consistently, I look into splitting it; once it hits 15-20%, my
users start to get finicky. Our environment consists of a lot of
NFS/NIS activity and everyone runs X-apps all over the place, so slow
responses definitely get noticed. I would think that 25% load is the
most you would want to see on a sustained basis, remembering that if
you hit 40%, most of the traffic is going to be re-transmitted
collisions, at which point the re-transmitted collisions cause
collisions - you get the picture.

    - henrik

Henrik Schmiediche, Dept. of Statistics, Texas A&M, College Station, TX 77843
E-mail:  |  Tel: (409) 862-1764   |  Fax: (409) 845-3144
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