I would like to implement the 100Mbps single pair automotive ethernet specified in 802.3bw, otherwise known as 100BASE-T1. I was told that in order to troubleshoot and test on this standard, the scope must be capable of 1 Ghz. Is this accurate? Why would this be necessary as opposed to an oscilloscope that is well above 100MHz such as one that is 200MHz, but still 1 GSa/s ?
Sounds like you want a protocol tester more than you want an oscilloscope. But oh well, that's not the question here.
I was told that in order to troubleshoot and test on this standard, the scope must be capable of 1 GHz
No. Even wikipedia will tell you that it only requires CAT3 cabling, and that doesn't guarantee a bandwidth even close to that.
Ah, with your comment:
Only looking for network traffic analysis at this point
yeah, well, then an oscilloscope in itself is no use at all. You'll need a device that speaks that protocol. For some higher-end, there might be add-ons that implement such a protocol decoder. But that again has nothing to do with the scope's 1 GHz bandwidth or not – it's something that extends the signal processing capabilities of the scope, and "converts" it into a protocol analyzer.
Since this is an ethernet standard, in principle, a network card connecting your device A to a PC, which sniffs and forwards the packets in both directions, and another network card for PC <-> device B would sound like a saner investment than an oscilloscope.
There are two aspects to Ethernet connectivity: signal integrity and content. You’d use an oscilloscope with suitable differential probes to capture the raw signals and analyze them with (usually) an Ethernet signal analysis package on the oscilloscope. That’s probably over $10k worth of equipment - if you aren’t in that line of work, you’d do a rental. Without that, you won’t probably be able to verify that the signal is fully within specs since you won’t have bit error rate measurements and such, but at least you can get an eye diagram and make sure it fits the masks prescribed for the physical layer you chose. For 100BASE-T-anything I’d probably look for a 5Gs/s at least - otherwise there are way too few samples per clock period to make it convincing (or even usable if you are diagnosing signal integrity issues vs. merely confirming that things work).
The content aspect is taken care of by wireshark and a PC :)