Summary of ethernet switch discussion

[john sinclair <sinclair@mail.phy.ornl.gov>]

The following summarizes the ethernet switch discussion:


Man/Model		Problems
----------		-----------------------
Cisco 2912		None

Cisco 2916M		Random disconnections
			(This was reported by a non-EPICS user
                         (Inland Steel Co.) who uses many Cisco 29xx
                         devices)

Cisco 2924		None

Cisco 35xx		None

Cabletron SS2200	None

Cabletron SS6000	None

3COM 3900		large number of errors can cause switch
			to stop working (prior to firmware upgrade)


Other comments:


John Hammonds

We have found that some NICs have trouble deciding for 10 or 100 Mbit.
Esp. PC card NICs.  This is probably a problem with the NIC though.


Paul Sichta

Our only "network problem" was with the CA broadcast; The AB PLC-5/40E
(Model # 1785L40E) will temporarily disconnect (minutes, as I recall) from
the network if there is "too much" network traffic.  We have a lot of
traffic due to the broadcasts when people launch medm screens, as well as
other CA client activity.

The drop out problem was attributed to a "Throttle Back " feature
built in the ethernet PLC's so that the PLC process has priority over
E-net traffic.

(My comment) This is, of course, Allen-Bradley's problem. We have had
some problems with Allen-Bradley PLCs interacting with Windows broadcasts.


Bobby Whitus

We are currently using 3COM 3900s as our top level switches.  These
switches have 36 10/100 ports and up to 3 Gigabit ports. Overall they
work well..
We have seen problems where a large number of errors on a port could cause
to switch to stop working.  We recently installed a new firmware version
that will isolate ports with excessive errors.  We have not seen any
problems since then.

This model is a couple of years old.  It provided the best value for our
needs when we purchased them.  If I were doing it again today, I would
look at the new CISCO 10/100/1000 switches.


Pete Jemian

Cisco 3524-XL-A
Just received three of them
Easy to set up, 24 ports each, auto-negotiating
Each switch provides a WWW server for configuration management
Also can telnet into the switch
Also provides 2 each gigabit uplinks (GBIC)
Can't tell you about performance yet
Bought them on recommendation of Steve Wasserman, COM-CAT (our neighbor)


Thanks to all who responded.


John Sinclair
sinclair@mail.phy.ornl.gov
Oak Ridge National Lab
865-576-6362   865-574-1268 (fax)