daly@cisco.com (Tom Daly) (09/13/90)
>> >> I received a message from pat@hprnd.hp.com. It mentions 10baset incompatibility >> and recommends not to attach cisco to synoptics. Unfortunately, we does attach >> all cisco to synoptics through ods. Is it true? If it is, how we can avoid >> it. Thanks. Recently there has been some discussion on this list about cisco's interoperability with various wiring concentrators and/or Ethernet on twisted pair systems. I would like to clarify the situation: cisco has many installations working and interoperates with this equipment quite well in general. There are some implementations of networks with repeaters which violate 802.3 specifications by sending extra 'dribble' bits at the end of a frame. If these frames are received by a cisco router, a framing error is (correctly) reported and the packet is dropped. Since we found it easier for us to modify our microcode than for other vendors to correct their equipment, we have, starting with MCI microcode version 1.7 (which is currently shipping), modified our microcode to ignore framing errors. This was done with the belief that it is better to allow interoperability in these cases, rather than enforce the 802.3 specifications. To determine if this upgrade may be necessary, look for rapidly incrementing frame input errors using the command "show interface ether xx", and examine the version of MCI firmware with "show controller mci". If anyone believes that they are experiencing this problem, please contact customer-service@cisco.com to arrange for an upgrade. Thomas Daly Director, Hardware Engineering cisco Systems, Inc. daly@cisco.com
JOHN@heap.cisco.com (John Wright) (09/13/90)
Running cisco 1.7 ucode version MCIs requires system ROM version 8.1(19) or later code. John Wright Customer Engineering cisco Systems, Inc. -------
mikes%tektronix.tek.com@RELAY.CS.NET (Mike Skrydlak -- Tektronix Network Services) (09/14/90)
Are you SURE MCI 1.7 is incompatible with 8.1 (14) ? ps: I know 8.1 (19) has other merits, but I didn't think it was required for 1.7 .
wenker@ferris.cray.com (Joe Wenker) (09/14/90)
> Running cisco 1.7 ucode version MCIs requires system ROM version 8.1(19) > or later code. What level of MEC-6 ucode is comparable to version 1.7 ucode for an MCI? Joe Wenker Cray Research, INC.
daly@cisco.com (Tom Daly) (09/17/90)
One thing that I failed to mention regarding the 'dribble' problem is that it would be quite repeatable and show up as a failure of hosts to communicate. Greg's comments regarding misc fragments showing up as framing errors are valid If repeater equipment is generating dribbles, then you would get symptoms like host A can't talk to host B through a path that includes a wiring system and a router. Since many other things can cause this, an additional symptom to look for is the framing errors. Ideally, one would start with something like A can't talk to B, and on a lightly used net, everytime A tried the framing error count would bump. i.e., correlate the inability of hosts to communicate with the framing errors, as opposed to looking for a background level of framing errors on the net. Tom Daly