by Ann Demirtjis
Folks, Notes from the open issues BOF. Please review and modify as needed. I wasn't able to catch the name of the folks during the introductions. I think Jonathan has the list. Ann Open Issues BOF
Introductions Issues
1. Early media:
1. Possible solutions: 1. use INFO to pass ACM issues in interworking w/ ISUP. Problem: Early media also needed for Q931 interworking.
2. 2. Forget 183s. Use a one way 200 OK and then do a re-INVITE to get both ways going. What about post-dial delays? Reasons for wanting early media: Billing issue for PSTN interworking. Not cutting off voice. QoS negotiation (doing PRACK). If don't care about QoS negotiation, no need to do 183s.
3. Make it a MAY rather than a MUST. 183 done if client includes a header saying it is willing to do this. PRACKs become optional. Keep requirement that as soon as u send INVITE u are willing to accept media on the port advertised before getting a 200OK. Cannot send DTMF until after the 200OK has been received. Make early media a separate draft. Sending a 183 w/ an SDP requires knowing the client is willing to accept such a message. Sending a 183 w/o a SDP is OK to any UAC. Valuable since 183s are a reliable 1xx that cannot be dropped by a proxy. Problem: for a lot of calls, dialed DTMFs are collected before the call is officially up. Requires bi-directional media. 200Ok means bi-directional media path has been established. It doesn't mean the call has been answered. For bi-directional, send a 280.
2. General way to handle SDP: no SDP means no change. INV w/ SDP, 200OK w/ SDP, no SDP in ACK. If send a re-INV w/ no SDP, 200OK must have same SDP as in original exchange (200OK). Still some open issues w/ 3pcc that need to be resolved later.
3. Response authorization. Current mechanism not fully specified. Proposal: Use AuthenticationInfo for MA. Signing responses: if signature fails, tear down the call (implementation specific?). Should be reviewed by security experts.
4. PGP: move to S/MIME. Henning & ?? to write draft. 5. Overlapping transactions: already being done w/ PRACKs and COMETs. Another issue is sending an INVITE and then another before getting a response to give a context. Proposal: Only worry about overlapping w/in an INVITE. Extensions defining new methods need to specify how overlapping impacts them w.r.t. INVITEs.
Agreed to start doing Interim meetings. Will try linking them to other mtgs / conferences people attend.