[mrtg] Re: Cabletron Systems

[Rich Adamson]

> Does anyone have experience with Cabletron Switches and routers and MRTG /
> RRD??
>
> Any insights?

I've worked with several different Ctron models owned by clients. Ctron
outsourced the design & manufacturing of some models to other companies,
and some of those were not very good. As I recall, the ELS-16TX was
a relabeled box from another well known "inexpensive" switch manufacturer
and it would go to sleep at odd times (would not forward any traffic).
Required a power cycle to bring it back, and the engineers that came out
to inspect the box indicated there was a engineering glitch within the
chipset that could never be fixed/resolved. Ctron eventually swapped 
them out at no cost to the client. SNMP seemed to work fine and return 
reasonably accurate data as I recall.

The SSR layer-3 switch had some snmp issues that essentially caused it
to count "most, but not all" packets twice. Don't know if later revisions
of their software fixed the problems. 

Not that you probably care all that much, but the majority of ethernet
switches under about $2k retail are not actually manufactured by the 
company whose name appears on the front panel (including many from 
very well known and reputable companies).  There are also some 
manufacturers that will buy 10,000 units (as an exampe only) from a
third party design/manufacturing company and put a well recognized
model number on the unit, and the next order of 10,000 will come from 
a different third party with the exact same description on the front.
(You'll usually find a "b" or "-2" behind the model number on the
rear.)

If you want to have some technical fun, rip the cover off one of your 
switches and find the ethernet chipset manufacturer and chip part
number. Go to their web site and read the specs for the chips, and
you'll wonder how the company whose name appears on the front panel
arrived at their sales/marketing data. 

For most ethernet switches, you really don't care much about port
utilization, memory use or CPU. The more current switches don't rely
on the cpu to do much other then to maintain relatively static
tables, snmp, etc. Memory is not used to buffer packets (like they 
are in layer-3 boxes), therefore there is nothing of interest for 
"most" layer-2 switches.

Monitoring dropped packets and errors are very important. You don't
care if a switch port is running at 1% or 100% utilization as long
as packets aren't being dropped. Therefore, monitoring the MIB2 counter 
for inbound and outbound dropped packet is important. The same for 
errors.


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