Session Description Protocol (SDP) Parameters

Created

  • 2001-06-15

Last Updated

  • 2026-10-09

Available Formats

media

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 8866: SDP: Session Description Protocol

Available Formats

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: SDP: Session Description Protocol

Note

Standards Track RFC preferred.

Available Formats

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: SDP: Session Description Protocol
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: SDP: Session Description Protocol

Available Formats

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: SDP: Session Description Protocol

Available Formats

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: SDP: Session Description Protocol

Available Formats

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: SDP: Session Description Protocol
  • RFC 8864: Negotiation Data Channels Using the Session Description Protocol (SDP)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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
attribute bc_program session NORMAL Sonia Compans; TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"; RFC 8859
attribute bc_service session NORMAL Sonia Compans; TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification"; RFC 8859
attribute bc_service_package session NORMAL Sonia Compans; TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 "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, EBU-FNS Coordinator; 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 (t140) IDENTICAL-PER-PT RFC 5576; RFC 8866; RFC 8859; RFC 8865
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; Simão 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
attribute inactive session, media, dcsa (t140), dcsa (msrp) NORMAL RFC 8866; RFC 8859; RFC 8865; RFC 8873
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; Simão 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, source NORMAL RFC 7273; RFC 8859
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; Simão 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
attribute PSCid session NORMAL Sonia Compans; TS 183 063 R3 ETSI TISPAN Technical Specification TS 183 063 "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
attribute recvonly session, media, dcsa (t140), dcsa (msrp) NORMAL RFC 8866; RFC 8859; RFC 8865; RFC 8873
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
attribute sendonly session, media, dcsa (t140), dcsa (msrp) NORMAL RFC 8866; RFC 8859; RFC 8865; RFC 8873
attribute sendrecv session, media, dcsa (t140), dcsa (msrp) NORMAL RFC 8866; RFC 8859; RFC 8865; RFC 8873
attribute sescap session CAUTION RFC 6871; RFC 8859
attribute setup session, media, dcsa (msrp) TRANSPORT RFC 4145; RFC 8859; RFC 8873
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; Simão 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; Simão Campos-Neto; RFC 8859
attribute T38FaxUdpFECMaxSpan media TBD ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010; Simão 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; Simão 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, source NORMAL RFC 7273; RFC 8859
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; Simão 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; Simão 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: The Session Description Protocol (SDP) Content Attribute
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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 Ringtone (CAT) service NORMAL 3GPP TS 24.182 v11.2.0; Dongwook Kim; RFC 8859
content g.3gpp.crs Stream associated with the 3GPP Customized Ringing Signal (CRS) service NORMAL 3GPP TS 24.183 v9.10.0 annex E; Dongwook Kim; RFC 8859
content g.3gpp.announcement-no-confirmation Stream associated with video announcement service without user confirmation NORMAL 3GPP TS 24.229

Semantics for the "group" SDP Attribute

Registration Procedure(s)

  • Standards Action

Reference

  • RFC 5888: The Session Description Protocol (SDP) Grouping Framework
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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 the endpoint IDENTICAL-PER-PT 3GPP TS 26.114 v16.3.0; Ozgur Oyman
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: Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Signaling Media Decoding Dependency in the Session Description Protocol (SDP)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Session Description Protocol (SDP) Extension for Setting Audio and Video Media Streams over Circuit-Switched Bearers in the Public Switched Telephone Network (PSTN)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Source-Specific Media Attributes in the Session Description Protocol (SDP)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Key Management Extensions for Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

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

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: Codec Control Messages in the RTP Audio-Visual Profile with Feedback (AVPF)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Quality of Service (QoS) Mechanism Selection in the Session Description Protocol (SDP)
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Session Description Protocol (SDP) Capability Negotiation
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Session Description Protocol (SDP) Capability Negotiation
  • RFC 6871: Session Description Protocol (SDP) Media Capabilities Negotiation

Available Formats

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: RTP Clock Source Signalling
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: RTP Clock Source Signalling
  • RFC 8859: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: A Framework for Session Description Protocol (SDP) Attributes When Multiplexing

Available Formats

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: Session Description Protocol (SDP) Offer/Answer Procedures for Stream Control Transmission Protocol (SCTP) over Datagram Transport Layer Security (DTLS) Transport

Available Formats

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: RTP Payload Format Restrictions

Available Formats

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: Session Description Protocol (SDP) Offer/Answer Procedures for Interactive Connectivity Establishment (ICE)
Name Description Change Controller Reference
No registrations at this time.

Contact Information

Name Contact URI Last Updated
3GPP Specifications Manager 3gppContact&etsi.org 2017-06-16
Brian Rosen br&brianrosen.net 2016-10-11
Dongwook Kim dongwook.kim&etsi.org 2026-01-15
Felix Poulin, EBU-FNS Coordinator poulin&ebu.ch 2016-11-17
Ozgur Oyman ozgur.oyman&intel.com 2019-11-06
Simão Campos-Neto simao.campos&itu.int 2019-07-30
Sonia Compans Sonia.Compans&etsi.org 2010-11-24

Footnotes

[1]

historic
[2]

historic; use fmtp as per RFC 2198