Internet Assigned Numbers Authority • Domains • Protocols • Numbers • About Session Description Protocol (SDP) Parameters Created 2001-06-15 Last Updated 2026-10-20 Available Formats [IMG] XML [IMG] HTML [IMG] TXT Registries Included Below • media • proto • bwtype • nettype • addrtype • enckey • attribute-name (formerly "att-field") • content SDP Parameters • Semantics for the "group" SDP Attribute • "rtcp-fb" Attribute Values • "ack" and "nack" Attribute Values • "depend" SDP Attribute Values • "cs-correlation" Attribute Values • Semantics for the "ssrc-group" SDP Attribute • SDP/RTSP key management protocol identifiers • Codec Control Messages • QoS Mechanism Tokens • SDP Capability Negotiation Option Tags • SDP Capability Negotiation Configuration Parameters Registry • Timestamp Reference Clock Source Parameters • Media Clock Source Parameters • Multiplexing Categories • association-usage Name Registry • RID Attribute Parameters • Candidate Attribute Extensions media Registration Procedure(s) Standards Action Reference [RFC 8866] Available Formats [IMG] CSV Type SDP Name Reference media audio [RFC 8866] media video [RFC 8866] media text [RFC 8866] media application [RFC 8866] media message [RFC 8866] media image [RFC 6466] media haptics [RFC 9993] proto Registration Procedure(s) RFC Required Reference [RFC 8866] Note Standards Track RFC preferred. Available Formats [IMG] CSV Type SDP Name Reference proto RTP/AVP [RFC 8866] proto udp [RFC 8866] proto vat [1] proto rtp [1] proto udptl [ITU-T Recommendation T.38, 'Procedures for real-time Group 3 facsimile communication over IP networks', June 1998. (Section 9)] proto TCP [RFC 4145] proto RTP/AVPF [RFC 4585] proto TCP/RTP/AVP [RFC 4571] proto RTP/SAVP [RFC 3711] proto TCP/BFCP [RFC 8856] proto TCP/TLS/BFCP [RFC 8856] proto TCP/TLS [RFC 8122] proto FLUTE/UDP [RFC-mehta-rmt-flute-sdp-05] proto TCP/MSRP [RFC 4975] proto TCP/TLS/MSRP [RFC 4975] proto DCCP [RFC 5762] proto DCCP/RTP/AVP [RFC 5762] proto DCCP/RTP/SAVP [RFC 5762] proto DCCP/RTP/AVPF [RFC 5762] proto DCCP/RTP/SAVPF [RFC 5762] proto RTP/SAVPF [RFC 5124] proto UDP/TLS/RTP/SAVP [RFC 5764] proto DCCP/TLS/RTP/SAVP [RFC 5764] proto UDP/TLS/RTP/SAVPF [RFC 5764] proto DCCP/TLS/RTP/SAVPF [RFC 5764] proto UDP/MBMS-FEC/RTP/AVP [RFC 6064] proto UDP/MBMS-FEC/RTP/SAVP [RFC 6064] proto UDP/MBMS-REPAIR [RFC 6064] proto FEC/UDP [RFC 6364] proto UDP/FEC [RFC 6364] proto TCP/MRCPv2 [RFC 6787] proto TCP/TLS/MRCPv2 [RFC 6787] proto PSTN [RFC 7195] proto UDP/TLS/UDPTL [RFC 7345] proto voice [RFC 2848] proto fax [RFC 2848] proto pager [RFC 2848] proto TCP/RTP/AVPF [RFC 7850] proto TCP/RTP/SAVP [RFC 7850] proto TCP/RTP/SAVPF [RFC 7850] proto TCP/DTLS/RTP/SAVP [RFC 7850] proto TCP/DTLS/RTP/SAVPF [RFC 7850] proto TCP/TLS/RTP/AVP [RFC 7850] proto TCP/TLS/RTP/AVPF [RFC 7850] proto TCP/WS/BFCP [RFC 8857] proto TCP/WSS/BFCP [RFC 8857] proto UDP/DTLS/SCTP [RFC 8841] proto TCP/DTLS/SCTP [RFC 8841] proto TCP/DTLS/BFCP [RFC 8856] proto UDP/BFCP [RFC 8856] proto UDP/TLS/BFCP [RFC 8856] bwtype Registration Procedure(s) Standards Action Reference [RFC 8866][RFC 8859] Available Formats [IMG] CSV Type SDP Name Mux Category Reference bwtype CT NORMAL [RFC 8866]; [RFC 8859] bwtype AS SUM [RFC 8866]; [RFC 8859] bwtype RS SUM [RFC 3556]; [RFC 8859] bwtype RR SUM [RFC 3556]; [RFC 8859] bwtype TIAS SPECIAL [RFC 3890]; [RFC 8859] nettype Registration Procedure(s) RFC Required Reference [RFC 8866] Available Formats [IMG] CSV Type SDP Name Usable addrtype Values Reference nettype IN IP4, IP6 [RFC 8866] nettype TN RFC2543 [RFC 2848] nettype ATM NSAP, GWID, E164 [RFC 3108] nettype PSTN E164 [RFC 7195] addrtype Registration Procedure(s) RFC Required Reference [RFC 8866] Available Formats [IMG] CSV Type SDP Name Reference addrtype IP4 [RFC 8866] addrtype IP6 [RFC 8866] addrtype NSAP [RFC 3108] addrtype GWID [RFC 3108] addrtype E164 [RFC 7195]; [RFC 3108] enckey Registration Procedure(s) REGISTRY OBSOLETED - No further registrations accepted Reference [RFC 8866] Available Formats [IMG] CSV Type SDP Name Reference enckey clear [RFC 8866] enckey base64 [RFC 8866] enckey uri [RFC 8866] enckey prompt [RFC 8866] attribute-name (formerly "att-field") Registration Procedure(s) Specification Required Expert(s) Flemming Andreasen Reference [RFC 8866][RFC 8864][RFC 8859] Available Formats [IMG] CSV Type SDP Name Usage Level Mux Category Reference attribute 3ge2ae media IDENTICAL [3GPP TS 24.229 12.14.0]; [Dongwook_Kim] attribute 3gpp_MaxRecvSDUSize session, media NORMAL [3GPP TS 26.114 v16.3.0]; [_3GPP_Specifications_Manager] attribute 3gpp_mtsi_app_adapt media IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] attribute 3gpp_sync_info session, media NORMAL [3GPP TS 26.114 v16.3.0]; [_3GPP_Specifications_Manager] attribute 3GPP-Adaptation-Support media CAUTION [RFC 6064]; [RFC 8859] attribute 3GPP-Asset-Information session, media CAUTION [RFC 6064]; [RFC 8859] attribute 3GPP-Integrity-Key session CAUTION [RFC 6064]; [RFC 8859] attribute 3GPP-QoE-Metrics session, media CAUTION [RFC 6064]; [RFC 8859] attribute 3GPP-SDP-Auth session CAUTION [RFC 6064]; [RFC 8859] attribute 3GPP-SRTP-Config media CAUTION [RFC 6064]; [RFC 8859] attribute 3gpp-videopostdecbufsize media CAUTION [RFC 6064]; [RFC 8859] attribute 3gpp.iut.replication session, media TBD [3GPP TS 24.337 10.7.0]; [Dongwook_Kim]; [RFC 8859] attribute aal2CPS media CAUTION [RFC 3108]; [RFC 8859] attribute aal2CPSSDUrate media CAUTION [RFC 3108]; [RFC 8859] attribute aal2sscs3661assured media CAUTION [RFC 3108]; [RFC 8859] attribute aal2sscs3661unassured media CAUTION [RFC 3108]; [RFC 8859] attribute aal2sscs3662 media CAUTION [RFC 3108]; [RFC 8859] attribute aal5sscop media CAUTION [RFC 3108]; [RFC 8859] attribute aalApp media CAUTION [RFC 3108]; [RFC 8859] attribute aalType media CAUTION [RFC 3108]; [RFC 8859] attribute abrParms media CAUTION [RFC 3108]; [RFC 8859] attribute abrSetup media CAUTION [RFC 3108]; [RFC 8859] attribute acap session, media INHERIT [RFC 5939]; [RFC 8859] attribute accept-types media, dcsa (msrp) TBD [RFC 4975]; [RFC 8859]; [RFC 8873] attribute accept-wrapped-types media, dcsa (msrp) TBD [RFC 4975]; [RFC 8859]; [RFC 8873] attribute acfg media SPECIAL [RFC 5939]; [RFC 8859] attribute alt media CAUTION [RFC 6064]; [RFC 8859] attribute alt-default-id media CAUTION [RFC 6064]; [RFC 8859] attribute alt-group session CAUTION [RFC 6064]; [RFC 8859] attribute altc media TRANSPORT [RFC 6947]; [RFC 8859] attribute anbr media IDENTICAL [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] attribute anycast media CAUTION [RFC 3108]; [RFC 8859] attribute atmmap media CAUTION [RFC 3108]; [RFC 8859] attribute atmQOSparms media CAUTION [RFC 3108]; [RFC 8859] attribute atmTrfcDesc media CAUTION [RFC 3108]; [RFC 8859] [Sonia_Compans]; [TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 attribute bc_program session NORMAL "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"]; [RFC 8859] [Sonia_Compans]; [TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 attribute bc_service session NORMAL "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"]; [RFC 8859] [Sonia_Compans]; [TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 attribute bc_service_package session NORMAL "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"]; [RFC 8859] attribute bcap session, media INHERIT [RFC 7006]; [RFC 8859] attribute bcastversion session NORMAL [RFC 5159]; [RFC 8859] attribute bcob media CAUTION [RFC 3108]; [RFC 8859] attribute bearerSigIE media CAUTION [RFC 3108]; [RFC 8859] attribute bearerType media CAUTION [RFC 3108]; [RFC 8859] attribute bfcpver media TBD [RFC 8856] attribute bundle-only media NORMAL [RFC 9143] attribute bw-info media IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] attribute cache media CAUTION [RFC 3108]; [RFC 8859] attribute calgextmap session, media NORMAL [RFC 7266]; [RFC 8859] attribute candidate media TRANSPORT [RFC 8839]; [RFC 8859] attribute capability media CAUTION [RFC 3108]; [RFC 8859] attribute cat session NORMAL [RFC 8866]; [RFC 8859] attribute cbrRate media CAUTION [RFC 3108]; [RFC 8859] attribute ccap session, media IDENTICAL [RFC 7006]; [RFC 8859] attribute ccc_list session NORMAL [3GPP TS 26.114 v16.3.0]; [_3GPP_Specifications_Manager] attribute cdsc session, media NORMAL [RFC 3407]; [RFC 8859] attribute cfw-id media NORMAL [RFC 6230]; [RFC 8859] attribute chain media CAUTION [RFC 3108]; [RFC 8859] attribute channel media NORMAL [RFC 6787]; [RFC 8859] attribute charset session NORMAL [RFC 8866]; [RFC 8859] attribute charset:iso8895-1 session NORMAL [RFC 8866]; [RFC 8859] attribute chatroom media TBD [RFC 7701]; [RFC 8859] attribute clir session, media TBD [RFC 2848]; [RFC 8859] attribute clkrec media CAUTION [RFC 3108]; [RFC 8859] attribute cmid media NORMAL [RFC 6787]; [RFC 8859] attribute cname source NORMAL [RFC 5576]; [RFC 8859] attribute codecconfig media CAUTION [RFC 3108]; [RFC 8859] attribute conf media CAUTION [RFC 3312]; [RFC 8859] attribute confid media TBD [RFC 8856]; [RFC 8859] attribute connection session, media TRANSPORT [RFC 4145]; [RFC 8859] attribute content media NORMAL [RFC 4796]; [RFC 8859] attribute content-desc session, media TBD [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute control session, media CAUTION [RFC 2326]; [RFC 7826]; [RFC 8859] attribute cpar session, media INHERIT [RFC 3407]; [RFC 8859] attribute cparmax session, media SPECIAL [RFC 3407]; [RFC 8859] attribute cparmin session, media SPECIAL [RFC 3407]; [RFC 8859] attribute cpsSDUsize media CAUTION [RFC 3108]; [RFC 8859] attribute creq session, media NORMAL [RFC 5939]; [RFC 8859] attribute cryptex session, media TRANSPORT [RFC 9335] attribute crypto media TRANSPORT [RFC 4568]; [RFC 8859] attribute cs-correlation media TBD [RFC 7195]; [RFC 8859] attribute csup session, media NORMAL [RFC 5939]; [RFC 8859] attribute curr media CAUTION [RFC 3312]; [RFC 8859] attribute dccp-port media CAUTION [RFC 6773]; [RFC 8859] attribute dccp-service-code media CAUTION [RFC 5762]; [RFC 8859] attribute dcmap media SPECIAL [RFC 8864] attribute dcsa media SPECIAL [RFC 8864] attribute depend media IDENTICAL-PER-PT [RFC 5583]; [RFC 8859] attribute des media CAUTION [RFC 3312]; [RFC 8859] attribute dsel media CAUTION [RFC 3108]; [RFC 8859] attribute duplication-delay session, media NORMAL [RFC 7197]; [RFC 8859] attribute ebuacip media TBD [EBU Tech 3368 - Audio Contribution over IP – Profiles]; [Felix_Poulin]; [RFC 8859] attribute ecan media CAUTION [RFC 3108]; [RFC 8859] attribute ecn-capable-rtp media IDENTICAL [RFC 6679]; [RFC 8859] attribute eecid media CAUTION [RFC 3108]; [RFC 8859] attribute end-of-candidates session, media IDENTICAL [RFC 8840] attribute etag session, media CAUTION [RFC 2326]; [RFC 8859] attribute extmap session, media SPECIAL [RFC 8285]; [RFC 8859] attribute extmap-allow-mixed session, media IDENTICAL [RFC 8285] attribute fec media CAUTION [RFC 3108]; [RFC 8859] attribute FEC media NORMAL [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute FEC-declaration session, media TBD [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute FEC-OTI-extension session, media TBD [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute fec-repair-flow media SPECIAL [RFC 6364]; [RFC 8859] attribute fec-source-flow media SPECIAL [RFC 6364]; [RFC 8859] attribute file-date media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute file-disposition media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute file-icon media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute file-range media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute file-selector media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute file-transfer-id media, dcsa (msrp) TBD [RFC 5547]; [RFC 8859]; [RFC 8873] attribute fingerprint session, media TRANSPORT [RFC 8122]; [RFC 8859] attribute floorctrl media TBD [RFC 8856]; [RFC 8859] attribute floorid media TBD [RFC 8856]; [RFC 8859] attribute flute-ch session, media TBD [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute flute-tsi session, media TBD [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] attribute fmtp media, source, dcsa IDENTICAL-PER-PT [RFC 5576]; [RFC 8866]; [RFC 8859]; [RFC 8865] (t140) attribute framerate media IDENTICAL-PER-PT [RFC 8866]; [RFC 8859] attribute framesize media CAUTION [RFC 6064]; [RFC 8859] attribute fsel media CAUTION [RFC 3108]; [RFC 8859] attribute gc media CAUTION [RFC 3108]; [RFC 8859] attribute gpmd media TBD [ITU-T Rec. V.150.1]; [ITU-T Rec. V.152]; [Simao_Campos-Neto] attribute group session NORMAL [RFC 5888]; [RFC 8859] attribute h248item session, media SPECIAL [ITU-T H.248.15]; [RFC 8859] attribute hlang-recv media, dcsa (t140) NORMAL [RFC 8373]; [RFC 8865] attribute hlang-send media, dcsa (t140) NORMAL [RFC 8373]; [RFC 8865] attribute icap session, media NORMAL [RFC 7006]; [RFC 8859] attribute ice-lite session NORMAL [RFC 8839]; [RFC 8859] attribute ice-mismatch media NORMAL [RFC 8839]; [RFC 8859] attribute ice-options session NORMAL [RFC 8839]; [RFC 8859] attribute ice-pacing session NORMAL [RFC 8839] attribute ice-pwd session, media TRANSPORT [RFC 8839]; [RFC 8859] attribute ice-ufrag session, media TRANSPORT [RFC 8839]; [RFC 8859] attribute identity session NORMAL [RFC 8827] attribute ike-setup session, media IDENTICAL [RFC 6193]; [RFC 8859] attribute imageattr media IDENTICAL-PER-PT [RFC 6236]; [RFC 8859] session, media, attribute inactive dcsa (t140), dcsa NORMAL [RFC 8866]; [RFC 8859]; [RFC 8865]; [RFC 8873] (msrp) attribute ipbcp session SPECIAL [ITU-T Recommendation Q.1970, "BICC IP bearer control protocol" (07/2001)]; [RFC 8859] attribute isup_usi media CAUTION [RFC 3108]; [RFC 8859] attribute key-mgmt session, media IDENTICAL [RFC 4567]; [RFC 8859] attribute keywds session NORMAL [RFC 8866]; [RFC 8859] attribute label media NORMAL [RFC 4574]; [RFC 8859] attribute lang session, media NORMAL [RFC 8866]; [RFC 8859] attribute lcfg media SPECIAL [RFC 6871]; [RFC 8859] attribute lij media CAUTION [RFC 3108]; [RFC 8859] attribute loopback media NORMAL [RFC 6849]; [RFC 8859] attribute loopback-mirror media NORMAL [RFC 6849]; [RFC 8859] attribute loopback-source media NORMAL [RFC 6849]; [RFC 8859] attribute max-message-size media CAUTION [RFC 8841] attribute max-size media, dcsa (msrp) TBD [RFC 4975]; [RFC 8859]; [RFC 8873] attribute maxmptime media TBD [ITU-T Recommendation V.152 "Procedures for supporting voice-band data over IP networks", September 2010]; [Simao_Campos-Neto] attribute maxprate session, media SPECIAL [RFC 3890]; [RFC 8859] attribute maxptime media IDENTICAL-PER-PT [RFC 8866]; [RFC 8859] attribute mbms-flowid media CAUTION [RFC 6064]; [RFC 8859] attribute mbms-mode session, media CAUTION [RFC 6064]; [RFC 8859] attribute mbms-repair session, media CAUTION [RFC 6064]; [RFC 8859] attribute mediaclk session, media, NORMAL [RFC 7273]; [RFC 8859] source attribute mfcap session, media IDENTICAL-PER-PT [RFC 6871]; [RFC 8859] attribute mid media NORMAL [RFC 5888]; [RFC 8859] attribute mscap session, media INHERIT [RFC 6871]; [RFC 8859] attribute msid media NORMAL [RFC 8830] attribute msrp-cema media, dcsa (msrp) TBD [RFC 6714]; [RFC 8859]; [RFC 8873] attribute mtag session, media CAUTION [RFC 7826]; [RFC 8859] attribute multicast-rtcp session, media IDENTICAL [RFC 6128]; [RFC 8859] attribute omcap session, media NORMAL [RFC 6871]; [RFC 8859] attribute omr-codecs media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-m-att media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-m-bw media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-m-cksum media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-s-att media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-s-bw media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute omr-s-cksum media NORMAL [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute onewaySel media CAUTION [RFC 3108]; [RFC 8859] attribute orient media NORMAL [RFC 8866]; [RFC 8859] attribute orient:landscape media NORMAL [RFC 8866]; [RFC 8859] attribute orient:portrait media NORMAL [RFC 8866]; [RFC 8859] attribute orient:seascape media NORMAL [RFC 8866]; [RFC 8859] attribute path media, dcsa (msrp) TBD [RFC 4975]; [RFC 8859]; [RFC 8873] attribute pcfg media SPECIAL [RFC 5939]; [RFC 8859] attribute phone-context session, media TBD [RFC 2848]; [RFC 8859] attribute pmft media TBD [ITU-T Recommendation V.152 "Procedures for supporting voice-band data over IP networks", September 2010]; [Simao_Campos-Neto] attribute portmapping-req media CAUTION [RFC 6284]; [RFC 8859] attribute predefined_ROI media IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [_3GPP_Specifications_Manager] attribute previous-ssrc source NORMAL [RFC 5576]; [RFC 8859] attribute profileDesc media CAUTION [RFC 3108]; [RFC 8859] attribute prtfl media CAUTION [RFC 3108]; [RFC 8859] [Sonia_Compans]; [TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 attribute PSCid session NORMAL "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"]; [RFC 8859] attribute psk-fingerprint session, media IDENTICAL [RFC 6193]; [RFC 8859] attribute ptime media IDENTICAL-PER-PT [RFC 8866]; [RFC 8859] attribute Q763-INN session, media TBD [RFC 2848]; [RFC 8859] attribute Q763-nature session, media TBD [RFC 2848]; [RFC 8859] attribute Q763-plan session, media TBD [RFC 2848]; [RFC 8859] attribute qos-mech-recv session, media TRANSPORT [RFC 5432]; [RFC 8859] attribute qos-mech-send session, media TRANSPORT [RFC 5432]; [RFC 8859] attribute qosClass media CAUTION [RFC 3108]; [RFC 8859] attribute quality media NORMAL [RFC 8866]; [RFC 8859] attribute rams-updates media CAUTION [RFC 6285]; [RFC 8859] attribute range session, media CAUTION [RFC 2326]; [RFC 7826]; [RFC 8859] attribute record session, media TBD [RFC 7866]; [RFC 8859] attribute recordpref session, media TBD [RFC 7866]; [RFC 8859] session, media, attribute recvonly dcsa (t140), dcsa NORMAL [RFC 8866]; [RFC 8859]; [RFC 8865]; [RFC 8873] (msrp) attribute remote-candidates media TRANSPORT [RFC 8839]; [RFC 8859] attribute repair-window media SPECIAL [RFC 6364]; [RFC 8859] attribute require session, media TBD [RFC 2848]; [RFC 8859] attribute resource media NORMAL [RFC 6787]; [RFC 8859] attribute rid media SPECIAL [RFC 8851] attribute rmcap session, media IDENTICAL-PER-PT [RFC 6871]; [RFC 8859] attribute rtcp media TRANSPORT [RFC 3605]; [RFC 8859] attribute rtcp-fb media IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] attribute rtcp-idms media NORMAL [RFC 7272]; [RFC 8859] attribute rtcp-mux media IDENTICAL [RFC 5761]; [RFC 8035]; [RFC 8859] attribute rtcp-mux-only media IDENTICAL [RFC 8858] attribute rtcp-rgrp session, media IDENTICAL [RFC 8861]; [RFC 8859] attribute rtcp-rsize media IDENTICAL [RFC 5506]; [RFC 8859] attribute rtcp-unicast media IDENTICAL [RFC 5760]; [RFC 8859] attribute rtcp-xr session, media NORMAL [RFC 3611]; [RFC 8859] attribute rtpmap media IDENTICAL-PER-PT [RFC 8866]; [RFC 8859] attribute rtpred1 media CAUTION [2][RFC 8859] attribute rtpred2 media CAUTION [2][RFC 8859] attribute rtsp-ice-d-m session TBD [RFC 7825]; [RFC 8859] attribute rtt-mixer media NORMAL [RFC 9071, Section 2.3] attribute sbc media CAUTION [RFC 3108]; [RFC 8859] attribute sctp-port media CAUTION [RFC 8841] attribute sdplang session, media NORMAL [RFC 8866]; [RFC 8859] attribute secondary-realm media TRANSPORT [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] session, media, attribute sendonly dcsa (t140), dcsa NORMAL [RFC 8866]; [RFC 8859]; [RFC 8865]; [RFC 8873] (msrp) session, media, attribute sendrecv dcsa (t140), dcsa NORMAL [RFC 8866]; [RFC 8859]; [RFC 8865]; [RFC 8873] (msrp) attribute sescap session CAUTION [RFC 6871]; [RFC 8859] attribute setup session, media, TRANSPORT [RFC 4145]; [RFC 8859]; [RFC 8873] dcsa (msrp) attribute silenceSupp media CAUTION [RFC 3108]; [RFC 8859] attribute simulcast media NORMAL [RFC 8853] attribute source-filter session, media IDENTICAL [RFC 4570]; [RFC 8859] attribute sqn session, media NORMAL [RFC 3407]; [RFC 8859] attribute SRTPAuthentication media TBD [RFC 5159]; [RFC 8859] attribute SRTPROCTxRate media TBD [RFC 5159]; [RFC 8859] attribute ssrc media NORMAL [RFC 5576]; [RFC 8859] attribute ssrc-group media NORMAL [RFC 5576]; [RFC 8859] attribute stc media CAUTION [RFC 3108]; [RFC 8859] attribute stkmstream session, media NORMAL [RFC 5159]; [RFC 8859] attribute structure media CAUTION [RFC 3108]; [RFC 8859] attribute suspended session, media TBD [NENA STA-010.2-2016]; [Brian_Rosen]; [RFC 8859] attribute T38FaxFillBitRemoval media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxMaxBuffer media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxMaxDatagram media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxMaxIFP media TBD [ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [Simao_Campos-Neto]; [RFC 8859] attribute T38FaxRateManagement media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxTranscodingJBIG media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxTranscodingMMR media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxUdpEC media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38FaxUdpECDepth media TBD [ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [Simao_Campos-Neto]; [RFC 8859] attribute T38FaxUdpFECMaxSpan media TBD [ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [Simao_Campos-Neto]; [RFC 8859] attribute T38FaxVersion media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38MaxBitRate media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [RFC 8859] attribute T38ModemType media TBD [ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010]; [Simao_Campos-Neto]; [RFC 8859] attribute T38VendorInfo media TBD [ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', February 2000, July 2005.]; [RFC 8859] attribute tcap session, media INHERIT [RFC 5939]; [RFC 8859] attribute tls-id media IDENTICAL [RFC 8842] attribute tool session NORMAL [RFC 8866]; [RFC 8859] attribute tra-att session, media NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute tra-bw session, media NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute tra-contact session, media NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute tra-m-line media NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute tra-media-line-number session NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute tra-SCTP-association media NORMAL [http://www.3gpp.org/ftp/Specs/html-info/24229.htm]; [http://www.3gpp.org/ftp/Specs/html-info/24371.htm] attribute ts-refclk session, media, NORMAL [RFC 7273]; [RFC 8859] source attribute type session NORMAL [RFC 8866]; [RFC 8859] attribute type:H332 session NORMAL [ITU Recommendation H.332]; [RFC 8859] attribute type:broadcast session NORMAL [RFC 8866]; [RFC 8859] attribute type:meeting session NORMAL [RFC 8866]; [RFC 8859] attribute type:moderated session NORMAL [RFC 8866]; [RFC 8859] attribute type:test session NORMAL [RFC 8866]; [RFC 8859] attribute uiLayer1_Prot media CAUTION [RFC 3108]; [RFC 8859] attribute upcc media CAUTION [RFC 3108]; [RFC 8859] attribute userid media TBD [RFC 8856]; [RFC 8859] attribute v3cfmtp session, media NORMAL [RFC 10034] attribute vbd (OBSOLETE) media TBD [ITU-T Recommendation V.152 "Procedures for supporting voice-band data over IP networks", September 2010]; [Simao_Campos-Neto] attribute visited-realm media TRANSPORT [TS 24.229 v10.7.0 table 7.5.2]; [Dongwook_Kim]; [RFC 8859] attribute vndpar session, media TBD [ITU-T Rec. V.150.1]; [ITU-T Rec. V.152]; [Simao_Campos-Neto] attribute vsel media CAUTION [RFC 3108]; [RFC 8859] attribute websocket-uri media CAUTION [RFC 8124] attribute X-decbyterate media CAUTION [RFC 6064]; [RFC 8859] attribute X-initpostdecbufperiod media CAUTION [RFC 6064]; [RFC 8859] attribute X-initpredecbufperiod media CAUTION [RFC 6064]; [RFC 8859] attribute X-predecbufsize media CAUTION [RFC 6064]; [RFC 8859] attribute zrtp-hash media TRANSPORT [RFC 6189]; [RFC 8859] content SDP Parameters Registration Procedure(s) Specification Required Expert(s) Christer Holmberg Reference [RFC 4796][RFC 8859] Available Formats [IMG] CSV Type SDP Name Description Mux Category Reference content slides Presentation slides NORMAL [RFC 4796]; [RFC 8859] content speaker Image from the speaker NORMAL [RFC 4796]; [RFC 8859] content sl Sign language NORMAL [RFC 4796]; [RFC 8859] content main Main media stream NORMAL [RFC 4796]; [RFC 8859] content alt Alternative media stream NORMAL [RFC 4796]; [RFC 8859] content g.3gpp.cat Stream associated with the 3GPP Customized Alerting NORMAL [3GPP TS 24.182 v11.2.0]; [Dongwook_Kim]; Ringtone (CAT) service [RFC 8859] content g.3gpp.crs Stream associated with the 3GPP Customized Ringing NORMAL [3GPP TS 24.183 v9.10.0 annex E]; Signal (CRS) service [Dongwook_Kim]; [RFC 8859] content g.3gpp.announcement-no-confirmation Stream associated with video announcement service NORMAL [3GPP TS 24.229] without user confirmation Semantics for the "group" SDP Attribute Registration Procedure(s) Standards Action Reference [RFC 5888][RFC 8859] Available Formats [IMG] CSV Semantics Token Mux Category Reference Lip Synchronization LS NORMAL [RFC 5888]; [RFC 8859] Flow Identification FID NORMAL [RFC 5888]; [RFC 8859] Single Reservation flow SRF NORMAL [RFC 3524]; [RFC 8859] Alternative Network Address Types ANAT CAUTION [RFC 4091]; [RFC 8859] Forward Error Correction (Deprecated) FEC NORMAL [RFC 5956]; [RFC 8859] Forward Error Correction FR FEC-FR NORMAL [RFC 5956]; [RFC 8859] Composite Session CS NORMAL [RFC-mehta-rmt-flute-sdp-05]; [RFC 8859] Decoding Dependency DDP NORMAL [RFC 5583]; [RFC 8859] Duplication DUP NORMAL [RFC 7104]; [RFC 8859] Splice SPLICE TBD [RFC 8286]; [RFC 8859] Media bundling BUNDLE NORMAL [RFC 9143] CLUE-controlled "m=" line CLUE NORMAL [RFC 8848] V3C grouping V3C NORMAL [RFC 10034] "rtcp-fb" Attribute Values Registration Procedure(s) First Come First Served with permanent, stable, and publically accessible document. Reference [RFC 4585][RFC 8859] Available Formats [IMG] CSV Value Name Long Name Mux Category Reference ack Positive acknowledgement IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] app Application-defined parameter SPECIAL [RFC 4585]; [RFC 8859] ccm Codec Control Commands and Indications IDENTICAL-PER-PT [RFC 5104]; [RFC 8859] nack Negative Acknowledgement IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] trr-int Minimal receiver report interval IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] 3gpp-roi-arbitrary Video region-of-interest (ROI) arbitrarily selected by the endpoint IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] 3gpp-roi-predefined Video region-of-interest (ROI) pre-defined by the sender and selected by IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] the endpoint 3gpp-delay-budget Available or requested delay budget specified in milliseconds IDENTICAL-PER-PT [3GPP TS 26.114 v16.3.0]; [Ozgur_Oyman] 3gpp-viewport Viewport feedback for viewport-dependent 360-degree video IDENTICAL-PER-PT [3GPP TS 26.114] "ack" and "nack" Attribute Values Registration Procedure(s) First Come First Served with a permanent, stable, and publically accessible document Reference [RFC 4585][RFC 8859] Available Formats [IMG] CSV Value Name Long Name Usable with Mux Reference sli Slice Loss Indication nack IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] pli Picture Loss Indication nack IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] rpsi Reference Picture Selection Indication ack, nack IDENTICAL-PER-PT [RFC 4585]; [RFC 8859] app Application layer feedback ack, nack SPECIAL [RFC 4585]; [RFC 8859] rai Rapid Acquisition Indication nack IDENTICAL-PER-PT [RFC 6285]; [RFC 8859] tllei Transport-Layer Third-Party Loss Early Indication nack IDENTICAL-PER-PT [RFC 6642]; [RFC 8859] pslei Payload-Specific Third-Party Loss Early Indication nack IDENTICAL-PER-PT [RFC 6642]; [RFC 8859] ecn Explicit Congestion Notification nack IDENTICAL [RFC 6679]; [RFC 8859] ccfb Congestion Control Feedback ack IDENTICAL-PER-PT [RFC 8888] "depend" SDP Attribute Values Registration Procedure(s) Specification Required Expert(s) Stephan Wenger Reference [RFC 5583][RFC 8859] Available Formats [IMG] CSV Token Semantics Mux Category Reference lay Layered decoding dependency IDENTICAL-PER-PT [RFC 5583]; [RFC 8859] mdc Multi descriptive decoding dependency IDENTICAL-PER-PT [RFC 5583]; [RFC 8859] "cs-correlation" Attribute Values Registration Procedure(s) Specification Required Expert(s) Bo Burman Reference [RFC 7195][RFC 8859] Available Formats [IMG] CSV Value Description Mux Category Reference callerid Caller ID TBD [RFC 7195]; [RFC 8859] uuie User-User Information Element TBD [RFC 7195]; [RFC 8859] dtmf Dual-tone Multi-Frequency TBD [RFC 7195]; [RFC 8859] external External TBD [RFC 7195]; [RFC 8859] Semantics for the "ssrc-group" SDP Attribute Registration Procedure(s) Standards Action Reference [RFC 5576][RFC 8859] Available Formats [IMG] CSV Token Semantics Mux Category Reference FID Flow Identification NORMAL [RFC 5576]; [RFC 8859] FEC Forward Error Correction NORMAL [RFC 5576]; [RFC 8859] FEC-FR Forward Error Correction FR NORMAL [RFC 5956]; [RFC 8859] DUP Duplication NORMAL [RFC 7104]; [RFC 8859] SDP/RTSP key management protocol identifiers Registration Procedure(s) Specification Required Expert(s) Magnus Westerlund Reference [RFC 4567][RFC 8859] Note This registry of the key management protocol identifier, KMPID, has a name space that is shared between the SDP "key-mgmt" attribute and RTSP header "keymgmt". Available Formats [IMG] CSV Value Name Long Name Mux Category Reference mikey Multimedia Internet KEYing IDENTICAL [RFC 4567]; [RFC 8859] Codec Control Messages Registration Procedure(s) Specification Required Expert(s) Stephan Wenger Reference [RFC 5104][RFC 8859] Available Formats [IMG] CSV Value Name Long Name Usable with Mux Reference fir Full Intra Request Command ccm IDENTICAL-PER-PT [RFC 5104]; [RFC 8859] tmmbr Temporary Maximum Media Stream Bit Rate ccm IDENTICAL-PER-PT [RFC 5104]; [RFC 8859] tstr Temporal-Spatial Trade-off ccm IDENTICAL-PER-PT [RFC 5104]; [RFC 8859] vbcm H.271 video back channel messages ccm IDENTICAL-PER-PT [RFC 5104]; [RFC 8859] pause Media Pause/Resume ccm TBD [RFC 7728]; [RFC 8859] lrr Layer Refresh Request Command ccm IDENTICAL-PER-PT [RFC 9627] tsrr Temporal-Spatial Resolution ccm IDENTICAL-PER-PT [RFC-ietf-avtcore-rtcp-green-metadata-17, Section 6.1] QoS Mechanism Tokens Registration Procedure(s) Specification Required Expert(s) Christer Holmberg Reference [RFC 5432][RFC 8859] Available Formats [IMG] CSV QoS Mechanism Mux Category Reference rsvp TRANSPORT [RFC 5432]; [RFC 8859] nsis TRANSPORT [RFC 5432]; [RFC 8859] SDP Capability Negotiation Option Tags Registration Procedure(s) IETF Review Reference [RFC 5939][RFC 8859] Available Formats [IMG] CSV Option Tag Mux Category Reference cap-v0 NORMAL [RFC 5939]; [RFC 8859] med-v0 NORMAL [RFC 6871]; [RFC 8859] bcap-v0 NORMAL [RFC 7006]; [RFC 8859] ccap-v0 NORMAL [RFC 7006]; [RFC 8859] icap-v0 NORMAL [RFC 7006]; [RFC 8859] SDP Capability Negotiation Configuration Parameters Registry Registration Procedure(s) IETF Review Reference [RFC 5939][RFC 6871] Available Formats [IMG] CSV Encoding Name Descriptive Name Potential Configuration Definition Actual Configuration Definition Latent Configuration Definition a Attribute Configuration [RFC 5939] [RFC 5939] [RFC 6871] b Bandwidth [RFC 7006] [RFC 7006] [RFC 7006] c Connection Data [RFC 7006] [RFC 7006] [RFC 7006] i Title [RFC 7006] [RFC 7006] [RFC 7006] m Media Configuration [RFC 6871] [RFC 6871] [RFC 6871] mt Media Type [RFC 6871] [RFC 6871] [RFC 6871] pt Payload Type Number Mapping [RFC 6871] [RFC 6871] [RFC 6871] t Transport Protocol Configuration [RFC 5939] [RFC 5939] [RFC 6871] Timestamp Reference Clock Source Parameters Registration Procedure(s) Specification Required Expert(s) Magnus Westerlund Reference [RFC 7273][RFC 8859] Available Formats [IMG] CSV Name Long Name Mux Category Reference ntp Network Time Protocol NORMAL [RFC 7273, Section 4]; [RFC 8859] ptp Precision Time Protocol NORMAL [RFC 7273, Section 4]; [RFC 8859] gps Global Positioning System NORMAL [RFC 7273, Section 4]; [RFC 8859] gal Galileo NORMAL [RFC 7273, Section 4]; [RFC 8859] glonass Global Navigation Satellite System NORMAL [RFC 7273, Section 4]; [RFC 8859] local Local Clock NORMAL [RFC 7273, Section 4]; [RFC 8859] private Private Clock NORMAL [RFC 7273, Section 4]; [RFC 8859] Media Clock Source Parameters Registration Procedure(s) Specification Required Expert(s) Magnus Westerlund Reference [RFC 7273][RFC 8859] Available Formats [IMG] CSV Name Long Name Mux Category Reference sender Asynchronously Generated Media Clock NORMAL [RFC 7273, Section 5]; [RFC 8859] direct Direct-Referenced Media Clock NORMAL [RFC 7273, Section 5]; [RFC 8859] IEEE1722 IEEE1722 Media Stream Identifier NORMAL [RFC 7273, Section 5]; [RFC 8859] Multiplexing Categories Registration Procedure(s) Standards Action Reference [RFC 8859] Available Formats [IMG] CSV Multiplexing Categories Reference NORMAL [RFC 8859] CAUTION [RFC 8859] IDENTICAL [RFC 8859] TRANSPORT [RFC 8859] SUM [RFC 8859] INHERIT [RFC 8859] IDENTICAL-PER-PT [RFC 8859] SPECIAL [RFC 8859] TBD [RFC 8859] association-usage Name Registry Registration Procedure(s) First Come First Served Reference [RFC 8841] Available Formats [IMG] CSV Name Reference Change Controller webrtc-datachannel [RFC 8841]; [RFC 8832] IESG RID Attribute Parameters Registration Procedure(s) Specification Required Expert(s) Adam Roach Reference [RFC 8851] Available Formats [IMG] CSV RID Parameter Name Reference pt [RFC 8851] max-width [RFC 8851] max-height [RFC 8851] max-fps [RFC 8851] max-fs [RFC 8851] max-br [RFC 8851] max-pps [RFC 8851] max-bpp [RFC 8851] depend [RFC 8851] Candidate Attribute Extensions Registration Procedure(s) Specification Required Expert(s) Christer Holmberg Reference [RFC 8839] Name Description Change Controller Reference No registrations at this time. Contact Information ID Name Contact URI Last Updated [_3GPP_Specifications_Manager] 3GPP Specifications Manager mailto:3gppContact&etsi.org 2017-06-16 [Brian_Rosen] Brian Rosen mailto:br&brianrosen.net 2016-10-11 [Dongwook_Kim] Dongwook Kim mailto:info&3gpp.org 2026-10-20 [Felix_Poulin] Felix Poulin, EBU-FNS Coordinator mailto:poulin&ebu.ch 2016-11-17 [Ozgur_Oyman] Ozgur Oyman mailto:ozgur.oyman&intel.com 2019-11-06 [Simao_Campos-Neto] Simão Campos-Neto mailto:simao.campos&itu.int 2019-07-30 [Sonia_Compans] Sonia Compans mailto:Sonia.Compans&etsi.org 2010-11-24 Footnotes [1] historic [2] historic; use fmtp as per [RFC 2198] Licensing Terms