Core SIP Documents
RFC 2543 SIP: Session Initiation Protocol (obsolete)
RFC 3261 SIP: Session Initiation Protocol

SDP Related Documents
RFC 2327 Session Description Protocol (SDP)
RFC 3264 An Offer/Answer Model with the Session Description Protocol (SDP)
RFC 3266 Support of IPv6 in SDP
RFC 3388 Grouping Media Lines in SDP
RFC 3407 Session Description Protocol (SDP) Simple Capability Declaration
RFC 3556 SDP Bandwidth Modifiers for RTCP Bandwidth
RFC 3605 Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)
RFC 3890 A Transport Independent Bandwidth Modifier

RTP Related Documents
RFC 3550 RTP: Transport Protocol for Real-Time Applications
RFC 3551 RTP Profile for A/V Conferences with Minimal Control
RFC 2198 RTP Payload for Redundant Audio Data
RFC 2733 An RTP Payload Format for Generic Forward Error Correction
RFC 2793 RTP Payload for Text Conversation
RFC 2833 RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals
RFC 2959 Real-Time Transport Protocol Management Information Base
RFC 3389 RTP Payload for Comfort Noise
RFC 3611 RTP Control Protocol Extended Reports (RTCP XR)
RFC 3711 The Secure Real-time Transport Protocol (SRTP)

HTTP Related Documents
RFC 2616 Hypertext Transfer Protocol -- HTTP/1.1
RFC 2617 HTTP Authentication: Basic and Digest Access Authentication
RFC 3310 HTTP Digest Authentication Using Authentication and Key Agreement (AKA)
RFC 3310 HTTP Digest Authentication Using Authentication and Key Agreement (AKA)

MIME Related Documents
RFC 1847 Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted
RFC 2045 MIME Part One: Format of Internet Message Bodies
RFC 2046 MIME Part Two: Media Types
RFC 2047 MIME Part Three: Message Header Extensions for Non-ASCII Text
RFC 2048 MIME Part Four: Registration Procedures
RFC 2633 S/MIME Version 3 Message Specification
RFC 3204 MIME media types for ISUP and QSIG Objects
RFC 3420 Internet Media Type message/sipfrag
RFC 3555 MIME Type Registration of RTP Payload Formats

SIP Extension and Options
RFC 2976 The SIP INFO Method
RFC 2848 Extensions for IP Access to Telephone Call Services
RFC 3050 CGI for SIP
RFC 3262 Reliability of Provisional Responses
RFC 3263 Locating SIP Servers
RFC 3265 SIP-Specific Event Notification
RFC 3311 UPDATE Method
RFC 3312 Integration of Resource Management and SIP
RFC 3313 Private SIP Extensions for Media Authorization
RFC 3319 DHCPv6 Options for SIP Servers
RFC 3323 A Privacy Mechanism for SIP
RFC 3324 Short Term Requirements for Network Asserted Identity
RFC 3325 Private Extensions to SIP for Asserted Identity within Trusted Networks
RFC 3326 The Reason Header Field
RFC 3327 Extension Header Field for Registering Non-Adjacent Contacts
RFC 3329 Security Mechanism Agreement
RFC 3361 DHCP-for-IPv4 Option for SIP Servers
RFC 3372 SIP for Telephones (SIP-T): Context and Architectures
RFC 3398 ISUP to SIP Mapping
RFC 3428 SIP Extension for Instant Messaging
RFC 3455 Private Header Extensions for 3GPP
RFC 3515 The Session Initiation Protocol (SIP) Refer Method
RFC 3608 Extension Header Field for Service Route Discovery During Registration
RFC 3680 SIP Event Package for Registrations
RFC 3840 Indicating User Agent Capabilities in SIP
RFC 3841 Caller Preferences for SIP
RFC 3842 Message Summary and Message Waiting Indication Event Package
RFC 3856 Presence Event Package
RFC 3857 A Watcher Information Event Template-Package
RFC 3903 Event State Publication

SIP Informational
RFCs RFC 3087 Control of Service Context using SIP Request-URI
RFC 3351 User Requirements for SIP in Support of Speech/Hearing Impaired
RFC 3603 Private SIP Proxy-to-Proxy Extensions for PacketCable Distributed Call Signaling
RFC 3702 Authentication, Authorization, and Accounting Requirements for SIP
RFC 3824 Using E.164 numbers with SIP
RFC 3911 The SIP "Join" Header

SIP Related Documents
RFC 3219 Telephony Routing over IP (TRIP) (tutorial)
RFC 3320 Signalling Compression
RFC 3321 Signalling Compression - Extended Operations (informational)
RFC 3322 Signalling Compression - Requirements and Assumptions (informational)
RFC 3486 Compressing the Session Initiation Protocol (SIP)
RFC 3485 SIP and SDP Static Dictionary for Signaling Compression
RFC 3725 Best Current Practices for 3PCC in SIP
RFC 3764 enumservice registration for SIP Addresses-of-Record

Directory Services Documents
H.350 Directory Services Architecture for Multimedia Conferencing
H.350.4 Directory Services Architecture for SIP