Is it common or uncommon to fire up 'ethereal' or 'tcpdump' to debug a BGP problem?
I have done that a few times in my life (not that i have lived long enough like others in this list)
Would it be problematic to have to either a) clear sessions for your analyser to fully understand the BGP stream or b) tell your analyser
Are you're talking about clearing the BGP session between the two remote ends, for the *analyser* to work? This is weird and will most definitely not be accepted. There could be numerous such applications running that would want to look at the BGP stream. The peers are not expected to reset the session to make them work!
whether the flow uses 2 or 4 byte ASNs?
This would imply prior knowledge about the ASNs which may not be available with the analyser.
Essentially, this draft as it stands is going to make it difficult to observe and comprehend BGP AS_PATH without either human intervention or restart of the session(s) concerned. A guage how much of a problem this would be in real-life (if any problem at all?) would be useful in determining whether it's worth lobbying to change the draft.
If there isnt a wide installed base for the draft, and if there are solutions available that can solve this problem then i would prefer going ahead with the new solution and picking it up if it works! Kent