How can ethernet traffic be measured?

[David S. Herron]

>    Does UNIX provide any commands for gathering network performance
>    statistics?

>From my days as a system/network admin there's one piece of software
out there I wholeheartedly reccomend..  That's NNStat

NNStat is a daemon which runs on (at least) SunOS systems.  It puts
the interface into promiscuous mode and using the NIT driver (Network
Interface Tap) it starts grabbing all the packets it can possibly
grab on the network.

The configuration is a text file describing two things

	filters to limit what packets we're interested in looking at

	buckets into which to count the packets

You can attach different filters to different buckets.  You can filter
out some factors, then have a block of code which puts the remaining
packets into more precisely determined buckets.  etc etc etc ..

It's very nice.  But it isn't good for interactive looking at immediate
traffic patterns.  Instead it's meant for, and is very good at, seeing
the long term patterns.

The distribution contains awk scripts to crunch the raw data down
to textual reports.

It's available for anonymous ftp from venera.isi.edu.



Another thing for you to look at is a recent RFC on network management
and diagnostic tools.  This and many other packages/products are
mentioned in the RFC.  And there's a bit of an introduction to the
whole biz of network management.



Another way of getting statistics is via the SNMP (Simple Network Management
Protocol).  I'm not very familiar with it but my understanding is:

-- The main thing you do with the protocol is to access & change
   "variables" kept in each of the boxes on the network.
-- the boxes may be hosts or routers or individual processes within
   a host.
-- the variables tend to be things like packet counts and packet
   type counts and routing tables
-- you'd have a daemon and/or interactive agent at some place in
   the network polling the variables available within the local net.


I'm about to run out of information, it's a good thing I don't work
in that group here at TWG, huh? :-).  TWG has a product which does
this on Sun equipment.  So do many other vendors.  Ours is called
"Management Station".


-- 
<- David Herron, an MMDF & WIN/MHS guy, <david at twg.com>
<- Formerly: David Herron -- NonResident E-Mail Hack <david at ms.uky.edu>
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