1. A straw-man proposal for a media-based traceroute function for SIP draft-kaplan-straw-sip-traceroute-00 Hadriel Kaplan

2. The Problem(s) Troubleshooting failed or poor media calls is difficult – If you call a 911/112 test number and media is bad, what do you do next? In IP, people start running traceroute It would be nice to have the same for SIP media sessions Alice PBX App Server PBX How do we find out this is the problem? Bob

3. Can’t we use Max-Forwards? Kinda sorta but not really Problem-1: Max-Forwards gets reset by B2BUAs – Trying to address that in another straw draft Problem-2: Even if Max-Forwards works, the reached hop will respond with 483 error – Not what we want – we want it to answer the call

4. The Proposed Solution A new header (surprise!) – ‘B2bua-hops: 70’ Like Max-Forwards, this header gets decremented by middleboxes – but only media-plane B2BUAs When it reaches 0, the B2BUA answers it – Or responds with 483 if it can’t answer it, with Contact-URI Alice PBX App Server PBX B2bua-hops:2 B2bua-hops:1B2bua-hops:0 Answers Bob

5. Open Issues Lots of open issues – this is just a straw-man proposal after all But the big question right now: is anyone interested in this type of thing? Should we use a new header, or something in SDP?