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SIP 标准进展. SIP 标准化进展. Enterprise “PBX Features” NAT/FW traversal Security Caller ID Services and Privacy DTMF QoS Configuration/Management Gateways to Other Protocols/TDM. Enterprise User-Based “PBX Features” (1). Centrex Style Features Call Waiting / Multiple Calls RFC 3261
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SIP标准化进展 • Enterprise “PBX Features” • NAT/FW traversal • Security • Caller ID Services and Privacy • DTMF • QoS • Configuration/Management • Gateways to Other Protocols/TDM
Enterprise User-Based “PBX Features” (1) • Centrex Style Features • Call Waiting / Multiple Calls RFC 3261 • Hold RFC 3264 • Transfer RFC 3515 / Replaces • Conference RFC 3261 / RFC 3840 • Message Waiting RFC 3842 • Call Forward RFC 3261 • Park RFC 3515 / Replaces • Pickup Replaces • Do Not Disturb RFC 3261 • Call Coverage RFC 3261
Enterprise User-Based “PBX Features” (2) • Boss/Admin Features • Simultaneous Ringing RFC 3261 • Basic Shared Lines Dialog pkg (stable) / RFC 3680 • Barge-In Join (ready) • “Take” Replaces (ready) • Shared-Line “Privacy” Dialog pkg • Divert to Admin RFC 3261 • Intercom URI convention • Attendant Services • Auto-attendant RFC 3261 / RFC 2833 • Attendant Console Dialog pkg • Night Service RFC 3261
Perhaps we need Business “Feature Packs” for SIP Phones • Feature Pack “A” • Basic Call • Attended Transfer w/ REFER and Replaces • Caller ID and Privacy • Message Waiting • Basic Dial Plan • Basic Conferences • Feature Pack “X” • Integrated Presence (as NOTIFIER) • IM Receiver • Feature Pack “B” • Join • Dialog Package • Phone configuration • Shared Line support • click to dial using REFER • TLS • Autodial and autoanswer URIs • Feature Pack “C” • ENUM • Remote dialog manipulation with REFER • End-to-end encryption • Conference Roster
NAT/FW Traversal • SIP • Symmetric Response—RFC 3581 • Connection Reuse—SIP WG ID • Session Policy—Requirements done • Globally Routable URIs—IESG Review • Media • STUN—RFC 3489 • TURN—Individual ID • Protocol-specific Relays • ICE—to become an MMUSIC WG ID • B2BUAs with Media • Putting it all together • NAT scenarios—SIPPING WG ID
Security: Works really well • Authentication • Digest Authentication—RFC 2617 / RFC 3261 • Digest AKA for GSM SIM auth—RFC 3310 • Signaling protection • TLS (hop-by-hop)—In core spec • S/MIME (end-to-end)—In core spec • S/MIME AES—Minor update to core spec - RFC ed • Authenticated ID Body—AIB draft • End-to-Middle, Middle-to-end—Requirements • Media protection • SRTP—RFC 3711
Caller ID Services and Privacy • Identity • End-to-End—RFC 3261 • Transitive Trust Model—RFC 3325 • Asserted by Third Party—“Identity” Draft (Solid) • Privacy • Privacy Header—RFC 3323 • New privacy tokens for transitive trust • Role-based Authorization
DTMF / Digits • Time synchronized with media: it works • In-band (tones blended in with the speech codec) • RFC2833 “AVT Tones” • In “signaling”: it sucks • Many Proprietary Approaches • various payloads in INFO, SUB/NOT • All have some bad side effects • Double-Digits • Poor timing characteristics • Using Markup: it will work (Stable) • KPML • App Interaction Framework
QoS • Diffserv-style • Just set it (diffserv markings) • Intserv-style, post-ring • Just do it (send RSVP requests post-ring) • Intserv-style, pre-ring • QoS Preconditions—RFC 3313 • Alternate routing on QoS failure? • Just works. You get it for free.
Configuration and Management • Phone configuration • event package—Solid • config format—Mud • SIP MIB—Fairly Solid • TRIP and TGREP • TRIP is an RFC • TGREP is in AD review
PSTN Interworking Issues #1 • Early Media—No new extensions, BCP in works (Stable) • Basic Early Media works fine • Early Media + forking does not • If it hurts, don’t do that! • Overlap Dialing—RFC 3578 • It works. Providers can use three variations on the approach when receiving numbers in their network • Telephony-Specific Addressing—WG IDs in IPTEL • Calling Party Category / Nature of Party • Trunk Group and Carrier Codes • Number Portability indicator
PSTN Interworking Issues #2 • Redirection Information: 3 approaches • Put the info in the URI: works, requires no extensions, but most folks do not understand the idea. requires coordinated configuration between gateway and proxies • cc-diversion: proprietary. functional but with swiss cheese security • Request-History: Moist Clay • Emergency Services and Prioritized Call completion • 911/112 Calls: Works for fixed locations, Working on mobile locations. (PSTN 911 has the same problem) • MLPP and IEPS: Request-History—Stable • Tunnelling Telephony Signaling—DoneRFC 3398 / 3204 / 3372
Gateway Services • PSTN Gateways • ISUP, ISDN, E&M, FXO, FXS gateways have been working for years now. Millions of minutes each day. • QSIG Gateways • Basic calls and Caller ID works just fine • Mapping complex features is work in progress • H.323 Gateways • Works just as well as PSTN • Commercial deployments doing millions of basic calls per month