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Establish preferential treatment for sessions competing for destination UA resources, typically for telephony gateways. Enhance SIP Priority header influence, define default behavior, prioritize call completion, address errors, and open issues.
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SIP Resource Priority James Polk/Cisco Henning Schulzrinne/Columbia University 53rd IETF -- SIPPING
Resource-Priority Header • Goal: • establish preferential (or deferential...) treatment for sessions when competing for destination UA resources • typically telephony gateways (not necessarily PSTN) • usually MLPP, but could be gateway resources only • cf. SIP Priority header: influence treatment by human user 53rd IETF -- SIPPING
Changes since last time • Namespace.priority • e.g., dsn.flash,q735.0 • IANA registration procedure • Clearer definition of default behavior • overall goal: maximize call completion • Resource-Priority expected, but none • policy issue, recommend treat at default level • recipient doesn’t understand name space • policy issue, recommend ignore and treat as if no Resource-Priority header • recipient doesn’t understand priority level 53rd IETF -- SIPPING
Error behavior • 503 (Service Unavailable) if insufficient priority • Warning: 370 (Insufficient Bandwidth) • Open issue: separate codes? 53rd IETF -- SIPPING
Open issues • All comments integrated – new I-D after IETF53 • Minor issue: Accept-Resource-Priority? • Otherwise considered done • Authors request hand-off to SIP (since new header) for PS track 53rd IETF -- SIPPING