Hi-
Guess it's a matter of degree. DPC mentions:
and they quote $400.00. Not cheap in my book!
One could cobble up an ethernet enabled micro for about $50.00 or so. Reference:
Still, that's not inexpensive.
The only reason that we get really inexpesive ethernet PCI
cards is due to the very volume of the boards that are
made. Also, it has to be backed up with the PC's
extensive RAM and cpu speed.
ScottyUK mentions the "ease" of ethernet cables. I worked
for Cisco for awhile. In our lab, we had bins and bins
of ethernet cables. In the lab, it's fine. Out on the
floor? Well, that might be a different situation. I've
had my share of problems with ethernet cables (and
connectors). Did I need a one to one, or a crossover
cable? Did somebody bust off the retaining tab from the
cable and is it riding in the socket on a wing and a
prayer? Patch panels tend to degrade into indecipherable
rat's nests, even with the best of documentation and
even better intentions. And the RJ45 connectors are not
really designed to be outside of an office environment.
Finally, the more "interesting" situations:
1. How close to the 100Meter limit is the cable running?
2. Contamination of the cable and how will it reflect
for collision avoidance?
3. How many levels on the hubs? Did the hub die?
4. The same as #3 for switches.
5. Traffic already on the lan?
6. Duplicate IP addresses. Or DHCP servers dropping leases?
7. Dynamic routing protocols.
8. Viruses. O.K. now I've scared myself.
I'm stopping here.
These are the real toughies to solve.
And the ethernet frame with the TCP/IP packet usually
associated with it and one could find that the overhead
of the packet far exceeds the payload of the packet.
Don't get me wrong. I'm quite a fan of ethernet in LAN's
and non hostile environments. Don't even mind them doing
"mission critical" operations.
And, since I'm coming from the other side of the equasion,
one more on the equipment supplier side, if you guys
want ethernet, and don't mind paying the price, sure
there will be one of us that will be glad to have an
RJ45 socket on the critters we supply you with.
As a side issue, this was something that I was thinking
about today. If you guys are using ethernet, are you
also using simple network management protocol (SNMP)?
One could easily populate the "experimental" portions
of the MIB with their custom devices and use some of the
existing tools (like MRTG or RRD) for data collection
and presentation? Traps and snmpsets for process
control? Granted SNMP was designed to monitor and
control computer networks (and nodes), but the framework
is all there.
Just curious.
Again, not trying to start a flame war, just my thoughts.
Cheers,
Rich S.