zeleznik@cs.utah.edu (Mike Zeleznik) (11/27/90)
I am looking for a device to analyze physical signals on an Ethernet (e.g., fall time, jitter, dc/ac component), while being able to select the signals of interest based on higher level protocol information (like a protocol analyzer). For example, I may suspect that signals from a station at one end of a cable segment are badly degraded by the time they reach the other end. Since I usually do not have the option of isolating the network, I would like to hang a probe on the net, filter out only packets with appropriate src/dest addresses, and then obtain information about the actual physical signals associated with those packets. Of course, I can hang a scope on the cable, but I can not easily display only the packets of interest. One conceptual solution is a protocol analyzer with a trigger output, tied into a digital scope. It would also be nice if the device would allow analysis of signals on the AUI cables. We had a situation where a Sun Sparcstation, a Cabletron Multiport Transceiver, and an HP MAU, would not work together. The Sun would not see some packets destined for it, but a Sniffer attached to another port on the multiport would see them all. Replacing the HP MAU with a Cabletron MAU fixed the problem! It would have been nice to take a look at what was going on at the AUI level... The only product I have found so far is the "Network Quality Analyzer" (NQA), made by Logic Replacement Technology Ltd., distributed by American Spectrum (thanks to a net respondent long ago). This appears to do much of what we want (though it seems to be limited to the ethernet cable only), but it is expensive, and I'd like to know if there are any other options. While HP and Tektronix (especially their LP COM Division) have a wide range of testing devices, they do not seem to fit our needs (from what I have seen so far). I will summarize what I find to the net. Thanks in advance for any help. Mike Zeleznik zeleznik@cs.utah.edu 801-581-5617