Session Description Protocol (SDP) Parameters

Created: 2001-06-15
Last Updated: 2023-06-06
Available Formats: XML
HTML
Plain text

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

[RFC8866]

Available Formats

CSV

Type	SDP Name	Reference
media	audio	[RFC8866]
media	video	[RFC8866]
media	text	[RFC8866]
media	application	[RFC8866]
media	message	[RFC8866]
media	image	[RFC6466]

proto

Registration Procedure(s)

RFC Required

Reference

[RFC8866]

Note

Standards Track RFC preferred.

Available Formats

CSV

Type	SDP Name	Reference
proto	RTP/AVP	[RFC8866]
proto	udp	[RFC8866]
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	[RFC4145]
proto	RTP/AVPF	[RFC4585]
proto	TCP/RTP/AVP	[RFC4571]
proto	RTP/SAVP	[RFC3711]
proto	TCP/BFCP	[RFC8856]
proto	TCP/TLS/BFCP	[RFC8856]
proto	TCP/TLS	[RFC8122]
proto	FLUTE/UDP	[RFC-mehta-rmt-flute-sdp-05]
proto	TCP/MSRP	[RFC4975]
proto	TCP/TLS/MSRP	[RFC4975]
proto	DCCP	[RFC5762]
proto	DCCP/RTP/AVP	[RFC5762]
proto	DCCP/RTP/SAVP	[RFC5762]
proto	DCCP/RTP/AVPF	[RFC5762]
proto	DCCP/RTP/SAVPF	[RFC5762]
proto	RTP/SAVPF	[RFC5124]
proto	UDP/TLS/RTP/SAVP	[RFC5764]
proto	DCCP/TLS/RTP/SAVP	[RFC5764]
proto	UDP/TLS/RTP/SAVPF	[RFC5764]
proto	DCCP/TLS/RTP/SAVPF	[RFC5764]
proto	UDP/MBMS-FEC/RTP/AVP	[RFC6064]
proto	UDP/MBMS-FEC/RTP/SAVP	[RFC6064]
proto	UDP/MBMS-REPAIR	[RFC6064]
proto	FEC/UDP	[RFC6364]
proto	UDP/FEC	[RFC6364]
proto	TCP/MRCPv2	[RFC6787]
proto	TCP/TLS/MRCPv2	[RFC6787]
proto	PSTN	[RFC7195]
proto	UDP/TLS/UDPTL	[RFC7345]
proto	voice	[RFC2848]
proto	fax	[RFC2848]
proto	pager	[RFC2848]
proto	TCP/RTP/AVPF	[RFC7850]
proto	TCP/RTP/SAVP	[RFC7850]
proto	TCP/RTP/SAVPF	[RFC7850]
proto	TCP/DTLS/RTP/SAVP	[RFC7850]
proto	TCP/DTLS/RTP/SAVPF	[RFC7850]
proto	TCP/TLS/RTP/AVP	[RFC7850]
proto	TCP/TLS/RTP/AVPF	[RFC7850]
proto	TCP/WS/BFCP	[RFC8857]
proto	TCP/WSS/BFCP	[RFC8857]
proto	UDP/DTLS/SCTP	[RFC8841]
proto	TCP/DTLS/SCTP	[RFC8841]
proto	TCP/DTLS/BFCP	[RFC8856]
proto	UDP/BFCP	[RFC8856]
proto	UDP/TLS/BFCP	[RFC8856]

bwtype

Registration Procedure(s)

Standards Action

Reference

[RFC8866][RFC8859]

Available Formats

CSV

Type	SDP Name	Mux Category	Reference
bwtype	CT	NORMAL	[RFC8866][RFC8859]
bwtype	AS	SUM	[RFC8866][RFC8859]
bwtype	RS	SUM	[RFC3556][RFC8859]
bwtype	RR	SUM	[RFC3556][RFC8859]
bwtype	TIAS	SPECIAL	[RFC3890][RFC8859]

nettype

Registration Procedure(s)

RFC Required

Reference

[RFC8866]

Available Formats

CSV

Type	SDP Name	Usable addrtype Values	Reference
nettype	IN	IP4, IP6	[RFC8866]
nettype	TN	RFC2543	[RFC2848]
nettype	ATM	NSAP, GWID, E164	[RFC3108]
nettype	PSTN	E164	[RFC7195]

addrtype

Registration Procedure(s)

RFC Required

Reference

[RFC8866]

Available Formats

CSV

Type	SDP Name	Reference
addrtype	IP4	[RFC8866]
addrtype	IP6	[RFC8866]
addrtype	NSAP	[RFC3108]
addrtype	GWID	[RFC3108]
addrtype	E164	[RFC7195][RFC3108]

enckey

Registration Procedure(s)

REGISTRY OBSOLETED - No further registrations accepted

Reference

[RFC8866]

Available Formats

CSV

Type	SDP Name	Reference
enckey	clear	[RFC8866]
enckey	base64	[RFC8866]
enckey	uri	[RFC8866]
enckey	prompt	[RFC8866]

attribute-name (formerly "att-field")

Registration Procedure(s)

Specification Required

Expert(s)

Flemming Andreasen

Reference

[RFC8866][RFC8864][RFC8859]

Available Formats

CSV

Type	SDP Name	Usage Level	Mux Category	Reference
attribute	3ge2ae	media	IDENTICAL	[3GPP TS 24.229 12.14.0][Frederic_Firmin]
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	[RFC6064][RFC8859]
attribute	3GPP-Asset-Information	session, media	CAUTION	[RFC6064][RFC8859]
attribute	3GPP-Integrity-Key	session	CAUTION	[RFC6064][RFC8859]
attribute	3GPP-QoE-Metrics	session, media	CAUTION	[RFC6064][RFC8859]
attribute	3GPP-SDP-Auth	session	CAUTION	[RFC6064][RFC8859]
attribute	3GPP-SRTP-Config	media	CAUTION	[RFC6064][RFC8859]
attribute	3gpp-videopostdecbufsize	media	CAUTION	[RFC6064][RFC8859]
attribute	3gpp.iut.replication	session, media	TBD	[3GPP TS 24.337 10.7.0][Frederic_Firmin][RFC8859]
attribute	aal2CPS	media	CAUTION	[RFC3108][RFC8859]
attribute	aal2CPSSDUrate	media	CAUTION	[RFC3108][RFC8859]
attribute	aal2sscs3661assured	media	CAUTION	[RFC3108][RFC8859]
attribute	aal2sscs3661unassured	media	CAUTION	[RFC3108][RFC8859]
attribute	aal2sscs3662	media	CAUTION	[RFC3108][RFC8859]
attribute	aal5sscop	media	CAUTION	[RFC3108][RFC8859]
attribute	aalApp	media	CAUTION	[RFC3108][RFC8859]
attribute	aalType	media	CAUTION	[RFC3108][RFC8859]
attribute	abrParms	media	CAUTION	[RFC3108][RFC8859]
attribute	abrSetup	media	CAUTION	[RFC3108][RFC8859]
attribute	acap	session, media	INHERIT	[RFC5939][RFC8859]
attribute	accept-types	media, dcsa (msrp)	TBD	[RFC4975][RFC8859][RFC8873]
attribute	accept-wrapped-types	media, dcsa (msrp)	TBD	[RFC4975][RFC8859][RFC8873]
attribute	acfg	media	SPECIAL	[RFC5939][RFC8859]
attribute	alt	media	CAUTION	[RFC6064][RFC8859]
attribute	alt-default-id	media	CAUTION	[RFC6064][RFC8859]
attribute	alt-group	session	CAUTION	[RFC6064][RFC8859]
attribute	altc	media	TRANSPORT	[RFC6947][RFC8859]
attribute	anbr	media	IDENTICAL	[3GPP TS 26.114 v16.3.0][Ozgur_Oyman]
attribute	anycast	media	CAUTION	[RFC3108][RFC8859]
attribute	atmmap	media	CAUTION	[RFC3108][RFC8859]
attribute	atmQOSparms	media	CAUTION	[RFC3108][RFC8859]
attribute	atmTrfcDesc	media	CAUTION	[RFC3108][RFC8859]
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"][RFC8859]
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"][RFC8859]
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"][RFC8859]
attribute	bcap	session, media	INHERIT	[RFC7006][RFC8859]
attribute	bcastversion	session	NORMAL	[RFC5159][RFC8859]
attribute	bcob	media	CAUTION	[RFC3108][RFC8859]
attribute	bearerSigIE	media	CAUTION	[RFC3108][RFC8859]
attribute	bearerType	media	CAUTION	[RFC3108][RFC8859]
attribute	bfcpver	media	TBD	[RFC8856]
attribute	bundle-only	media	NORMAL	[RFC9143]
attribute	bw-info	media	IDENTICAL-PER-PT	[3GPP TS 26.114 v16.3.0][Ozgur_Oyman]
attribute	cache	media	CAUTION	[RFC3108][RFC8859]
attribute	calgextmap	session, media	NORMAL	[RFC7266][RFC8859]
attribute	candidate	media	TRANSPORT	[RFC8839][RFC8859]
attribute	capability	media	CAUTION	[RFC3108][RFC8859]
attribute	cat	session	NORMAL	[RFC8866][RFC8859]
attribute	cbrRate	media	CAUTION	[RFC3108][RFC8859]
attribute	ccap	session, media	IDENTICAL	[RFC7006][RFC8859]
attribute	ccc_list	session	NORMAL	[3GPP TS 26.114 v16.3.0][_3GPP_Specifications_Manager]
attribute	cdsc	session, media	NORMAL	[RFC3407][RFC8859]
attribute	cfw-id	media	NORMAL	[RFC6230][RFC8859]
attribute	chain	media	CAUTION	[RFC3108][RFC8859]
attribute	channel	media	NORMAL	[RFC6787][RFC8859]
attribute	charset	session	NORMAL	[RFC8866][RFC8859]
attribute	charset:iso8895-1	session	NORMAL	[RFC8866][RFC8859]
attribute	chatroom	media	TBD	[RFC7701][RFC8859]
attribute	clir	session, media	TBD	[RFC2848][RFC8859]
attribute	clkrec	media	CAUTION	[RFC3108][RFC8859]
attribute	cmid	media	NORMAL	[RFC6787][RFC8859]
attribute	cname	source	NORMAL	[RFC5576][RFC8859]
attribute	codecconfig	media	CAUTION	[RFC3108][RFC8859]
attribute	conf	media	CAUTION	[RFC3312][RFC8859]
attribute	confid	media	TBD	[RFC8856][RFC8859]
attribute	connection	session, media	TRANSPORT	[RFC4145][RFC8859]
attribute	content	media	NORMAL	[RFC4796][RFC8859]
attribute	content-desc	session, media	TBD	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	control	session, media	CAUTION	[RFC2326][RFC7826][RFC8859]
attribute	cpar	session, media	INHERIT	[RFC3407][RFC8859]
attribute	cparmax	session, media	SPECIAL	[RFC3407][RFC8859]
attribute	cparmin	session, media	SPECIAL	[RFC3407][RFC8859]
attribute	cpsSDUsize	media	CAUTION	[RFC3108][RFC8859]
attribute	creq	session, media	NORMAL	[RFC5939][RFC8859]
attribute	cryptex	session, media	TRANSPORT	[RFC9335]
attribute	crypto	media	TRANSPORT	[RFC4568][RFC8859]
attribute	cs-correlation	media	TBD	[RFC7195][RFC8859]
attribute	csup	session, media	NORMAL	[RFC5939][RFC8859]
attribute	curr	media	CAUTION	[RFC3312][RFC8859]
attribute	dccp-port	media	CAUTION	[RFC6773][RFC8859]
attribute	dccp-service-code	media	CAUTION	[RFC5762][RFC8859]
attribute	dcmap	media	SPECIAL	[RFC8864]
attribute	dcsa	media	SPECIAL	[RFC8864]
attribute	depend	media	IDENTICAL-PER-PT	[RFC5583][RFC8859]
attribute	des	media	CAUTION	[RFC3312][RFC8859]
attribute	dsel	media	CAUTION	[RFC3108][RFC8859]
attribute	duplication-delay	session, media	NORMAL	[RFC7197][RFC8859]
attribute	ebuacip	media	TBD	[EBU Tech 3368 - Audio Contribution over IP – Profiles][Felix_Poulin][RFC8859]
attribute	ecan	media	CAUTION	[RFC3108][RFC8859]
attribute	ecn-capable-rtp	media	IDENTICAL	[RFC6679][RFC8859]
attribute	eecid	media	CAUTION	[RFC3108][RFC8859]
attribute	end-of-candidates	session, media	IDENTICAL	[RFC8840]
attribute	etag	session, media	CAUTION	[RFC2326][RFC8859]
attribute	extmap	session, media	SPECIAL	[RFC8285][RFC8859]
attribute	extmap-allow-mixed	session, media	IDENTICAL	[RFC8285]
attribute	fec	media	CAUTION	[RFC3108][RFC8859]
attribute	FEC	media	NORMAL	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	FEC-declaration	session, media	TBD	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	FEC-OTI-extension	session, media	TBD	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	fec-repair-flow	media	SPECIAL	[RFC6364][RFC8859]
attribute	fec-source-flow	media	SPECIAL	[RFC6364][RFC8859]
attribute	file-date	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	file-disposition	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	file-icon	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	file-range	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	file-selector	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	file-transfer-id	media, dcsa (msrp)	TBD	[RFC5547][RFC8859][RFC8873]
attribute	fingerprint	session, media	TRANSPORT	[RFC8122][RFC8859]
attribute	floorctrl	media	TBD	[RFC8856][RFC8859]
attribute	floorid	media	TBD	[RFC8856][RFC8859]
attribute	flute-ch	session, media	TBD	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	flute-tsi	session, media	TBD	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
attribute	fmtp	media, source, dcsa (t140)	IDENTICAL-PER-PT	[RFC5576][RFC8866][RFC8859][RFC8865]
attribute	framerate	media	IDENTICAL-PER-PT	[RFC8866][RFC8859]
attribute	framesize	media	CAUTION	[RFC6064][RFC8859]
attribute	fsel	media	CAUTION	[RFC3108][RFC8859]
attribute	gc	media	CAUTION	[RFC3108][RFC8859]
attribute	gpmd	media	TBD	[ITU-T Rec. V.150.1][ITU-T Rec. V.152][Simao_Campos-Neto]
attribute	group	session	NORMAL	[RFC5888][RFC8859]
attribute	h248item	session, media	SPECIAL	[ITU-T H.248.15][RFC8859]
attribute	hlang-recv	media, dcsa (t140)	NORMAL	[RFC8373][RFC8865]
attribute	hlang-send	media, dcsa (t140)	NORMAL	[RFC8373][RFC8865]
attribute	icap	session, media	NORMAL	[RFC7006][RFC8859]
attribute	ice-lite	session	NORMAL	[RFC8839][RFC8859]
attribute	ice-mismatch	media	NORMAL	[RFC8839][RFC8859]
attribute	ice-options	session	NORMAL	[RFC8839][RFC8859]
attribute	ice-pacing	session	NORMAL	[RFC8839]
attribute	ice-pwd	session, media	TRANSPORT	[RFC8839][RFC8859]
attribute	ice-ufrag	session, media	TRANSPORT	[RFC8839][RFC8859]
attribute	identity	session	NORMAL	[RFC8827]
attribute	ike-setup	session, media	IDENTICAL	[RFC6193][RFC8859]
attribute	imageattr	media	IDENTICAL-PER-PT	[RFC6236][RFC8859]
attribute	inactive	session, media, dcsa (t140), dcsa (msrp)	NORMAL	[RFC8866][RFC8859][RFC8865][RFC8873]
attribute	ipbcp	session	SPECIAL	[ITU-T Recommendation Q.1970, "BICC IP bearer control protocol" (07/2001)][RFC8859]
attribute	isup_usi	media	CAUTION	[RFC3108][RFC8859]
attribute	key-mgmt	session, media	IDENTICAL	[RFC4567][RFC8859]
attribute	keywds	session	NORMAL	[RFC8866][RFC8859]
attribute	label	media	NORMAL	[RFC4574][RFC8859]
attribute	lang	session, media	NORMAL	[RFC8866][RFC8859]
attribute	lcfg	media	SPECIAL	[RFC6871][RFC8859]
attribute	lij	media	CAUTION	[RFC3108][RFC8859]
attribute	loopback	media	NORMAL	[RFC6849][RFC8859]
attribute	loopback-mirror	media	NORMAL	[RFC6849][RFC8859]
attribute	loopback-source	media	NORMAL	[RFC6849][RFC8859]
attribute	max-message-size	media	CAUTION	[RFC8841]
attribute	max-size	media, dcsa (msrp)	TBD	[RFC4975][RFC8859][RFC8873]
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	[RFC3890][RFC8859]
attribute	maxptime	media	IDENTICAL-PER-PT	[RFC8866][RFC8859]
attribute	mbms-flowid	media	CAUTION	[RFC6064][RFC8859]
attribute	mbms-mode	session, media	CAUTION	[RFC6064][RFC8859]
attribute	mbms-repair	session, media	CAUTION	[RFC6064][RFC8859]
attribute	mediaclk	session, media, source	NORMAL	[RFC7273][RFC8859]
attribute	mfcap	session, media	IDENTICAL-PER-PT	[RFC6871][RFC8859]
attribute	mid	media	NORMAL	[RFC5888][RFC8859]
attribute	mscap	session, media	INHERIT	[RFC6871][RFC8859]
attribute	msid	media	NORMAL	[RFC8830]
attribute	msrp-cema	media, dcsa (msrp)	TBD	[RFC6714][RFC8859][RFC8873]
attribute	mtag	session, media	CAUTION	[RFC7826][RFC8859]
attribute	multicast-rtcp	session, media	IDENTICAL	[RFC6128][RFC8859]
attribute	omcap	session, media	NORMAL	[RFC6871][RFC8859]
attribute	omr-codecs	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-m-att	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-m-bw	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-m-cksum	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-s-att	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-s-bw	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	omr-s-cksum	media	NORMAL	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	onewaySel	media	CAUTION	[RFC3108][RFC8859]
attribute	orient	media	NORMAL	[RFC8866][RFC8859]
attribute	orient:landscape	media	NORMAL	[RFC8866][RFC8859]
attribute	orient:portrait	media	NORMAL	[RFC8866][RFC8859]
attribute	orient:seascape	media	NORMAL	[RFC8866][RFC8859]
attribute	path	media, dcsa (msrp)	TBD	[RFC4975][RFC8859][RFC8873]
attribute	pcfg	media	SPECIAL	[RFC5939][RFC8859]
attribute	phone-context	session, media	TBD	[RFC2848][RFC8859]
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	[RFC6284][RFC8859]
attribute	predefined_ROI	media	IDENTICAL-PER-PT	[3GPP TS 26.114 v16.3.0][_3GPP_Specifications_Manager]
attribute	previous-ssrc	source	NORMAL	[RFC5576][RFC8859]
attribute	profileDesc	media	CAUTION	[RFC3108][RFC8859]
attribute	prtfl	media	CAUTION	[RFC3108][RFC8859]
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"][RFC8859]
attribute	psk-fingerprint	session, media	IDENTICAL	[RFC6193][RFC8859]
attribute	ptime	media	IDENTICAL-PER-PT	[RFC8866][RFC8859]
attribute	Q763-INN	session, media	TBD	[RFC2848][RFC8859]
attribute	Q763-nature	session, media	TBD	[RFC2848][RFC8859]
attribute	Q763-plan	session, media	TBD	[RFC2848][RFC8859]
attribute	qos-mech-recv	session, media	TRANSPORT	[RFC5432][RFC8859]
attribute	qos-mech-send	session, media	TRANSPORT	[RFC5432][RFC8859]
attribute	qosClass	media	CAUTION	[RFC3108][RFC8859]
attribute	quality	media	NORMAL	[RFC8866][RFC8859]
attribute	rams-updates	media	CAUTION	[RFC6285][RFC8859]
attribute	range	session, media	CAUTION	[RFC2326][RFC7826][RFC8859]
attribute	record	session, media	TBD	[RFC7866][RFC8859]
attribute	recordpref	session, media	TBD	[RFC7866][RFC8859]
attribute	recvonly	session, media, dcsa (t140), dcsa (msrp)	NORMAL	[RFC8866][RFC8859][RFC8865][RFC8873]
attribute	remote-candidates	media	TRANSPORT	[RFC8839][RFC8859]
attribute	repair-window	media	SPECIAL	[RFC6364][RFC8859]
attribute	require	session, media	TBD	[RFC2848][RFC8859]
attribute	resource	media	NORMAL	[RFC6787][RFC8859]
attribute	rid	media	SPECIAL	[RFC8851]
attribute	rmcap	session, media	IDENTICAL-PER-PT	[RFC6871][RFC8859]
attribute	rtcp	media	TRANSPORT	[RFC3605][RFC8859]
attribute	rtcp-fb	media	IDENTICAL-PER-PT	[RFC4585][RFC8859]
attribute	rtcp-idms	media	NORMAL	[RFC7272][RFC8859]
attribute	rtcp-mux	media	IDENTICAL	[RFC5761][RFC8035][RFC8859]
attribute	rtcp-mux-only	media	IDENTICAL	[RFC8858]
attribute	rtcp-rgrp	session, media	IDENTICAL	[RFC8861][RFC8859]
attribute	rtcp-rsize	media	IDENTICAL	[RFC5506][RFC8859]
attribute	rtcp-unicast	media	IDENTICAL	[RFC5760][RFC8859]
attribute	rtcp-xr	session, media	NORMAL	[RFC3611][RFC8859]
attribute	rtpmap	media	IDENTICAL-PER-PT	[RFC8866][RFC8859]
attribute	rtpred1	media	CAUTION	[2][RFC8859]
attribute	rtpred2	media	CAUTION	[2][RFC8859]
attribute	rtsp-ice-d-m	session	TBD	[RFC7825][RFC8859]
attribute	rtt-mixer	media	NORMAL	[RFC9071, Section 2.3]
attribute	sbc	media	CAUTION	[RFC3108][RFC8859]
attribute	sctp-port	media	CAUTION	[RFC8841]
attribute	sdplang	session, media	NORMAL	[RFC8866][RFC8859]
attribute	secondary-realm	media	TRANSPORT	[TS 24.229 v10.7.0 table 7.5.2][Frederic_Firmin][RFC8859]
attribute	sendonly	session, media, dcsa (t140), dcsa (msrp)	NORMAL	[RFC8866][RFC8859][RFC8865][RFC8873]
attribute	sendrecv	session, media, dcsa (t140), dcsa (msrp)	NORMAL	[RFC8866][RFC8859][RFC8865][RFC8873]
attribute	sescap	session	CAUTION	[RFC6871][RFC8859]
attribute	setup	session, media, dcsa (msrp)	TRANSPORT	[RFC4145][RFC8859][RFC8873]
attribute	silenceSupp	media	CAUTION	[RFC3108][RFC8859]
attribute	simulcast	media	NORMAL	[RFC8853]
attribute	source-filter	session, media	IDENTICAL	[RFC4570][RFC8859]
attribute	sqn	session, media	NORMAL	[RFC3407][RFC8859]
attribute	SRTPAuthentication	media	TBD	[RFC5159][RFC8859]
attribute	SRTPROCTxRate	media	TBD	[RFC5159][RFC8859]
attribute	ssrc	media	NORMAL	[RFC5576][RFC8859]
attribute	ssrc-group	media	NORMAL	[RFC5576][RFC8859]
attribute	stc	media	CAUTION	[RFC3108][RFC8859]
attribute	stkmstream	session, media	NORMAL	[RFC5159][RFC8859]
attribute	structure	media	CAUTION	[RFC3108][RFC8859]
attribute	suspended	session, media	TBD	[NENA STA-010.2-2016][Brian_Rosen][RFC8859]
attribute	T38FaxFillBitRemoval	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxMaxBuffer	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxMaxDatagram	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxMaxIFP	media	TBD	[ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][Simao_Campos-Neto][RFC8859]
attribute	T38FaxRateManagement	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxTranscodingJBIG	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxTranscodingMMR	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxUdpEC	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38FaxUdpECDepth	media	TBD	[ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][Simao_Campos-Neto][RFC8859]
attribute	T38FaxUdpFECMaxSpan	media	TBD	[ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][Simao_Campos-Neto][RFC8859]
attribute	T38FaxVersion	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38MaxBitRate	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][RFC8859]
attribute	T38ModemType	media	TBD	[ITU-T Recommendation T.38 Annex D, 'SIP/SDP Call Establishment Procedures', September 2010][Simao_Campos-Neto][RFC8859]
attribute	T38VendorInfo	media	TBD	[ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', February 2000, July 2005.][RFC8859]
attribute	tcap	session, media	INHERIT	[RFC5939][RFC8859]
attribute	tls-id	media	IDENTICAL	[RFC8842]
attribute	tool	session	NORMAL	[RFC8866][RFC8859]
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	[RFC7273][RFC8859]
attribute	type	session	NORMAL	[RFC8866][RFC8859]
attribute	type:H332	session	NORMAL	[ITU Recommendation H.332][RFC8859]
attribute	type:broadcast	session	NORMAL	[RFC8866][RFC8859]
attribute	type:meeting	session	NORMAL	[RFC8866][RFC8859]
attribute	type:moderated	session	NORMAL	[RFC8866][RFC8859]
attribute	type:test	session	NORMAL	[RFC8866][RFC8859]
attribute	uiLayer1_Prot	media	CAUTION	[RFC3108][RFC8859]
attribute	upcc	media	CAUTION	[RFC3108][RFC8859]
attribute	userid	media	TBD	[RFC8856][RFC8859]
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][Frederic_Firmin][RFC8859]
attribute	vndpar	session, media	TBD	[ITU-T Rec. V.150.1][ITU-T Rec. V.152][Simao_Campos-Neto]
attribute	vsel	media	CAUTION	[RFC3108][RFC8859]
attribute	websocket-uri	media	CAUTION	[RFC8124]
attribute	X-decbyterate	media	CAUTION	[RFC6064][RFC8859]
attribute	X-initpostdecbufperiod	media	CAUTION	[RFC6064][RFC8859]
attribute	X-initpredecbufperiod	media	CAUTION	[RFC6064][RFC8859]
attribute	X-predecbufsize	media	CAUTION	[RFC6064][RFC8859]
attribute	zrtp-hash	media	TRANSPORT	[RFC6189][RFC8859]

content SDP Parameters

Registration Procedure(s)

Specification Required

Expert(s)

Christer Holmberg

Reference

[RFC4796][RFC8859]

Available Formats

CSV

Type	SDP Name	Description	Mux Category	Reference
content	slides	Presentation slides	NORMAL	[RFC4796][RFC8859]
content	speaker	Image from the speaker	NORMAL	[RFC4796][RFC8859]
content	sl	Sign language	NORMAL	[RFC4796][RFC8859]
content	main	Main media stream	NORMAL	[RFC4796][RFC8859]
content	alt	Alternative media stream	NORMAL	[RFC4796][RFC8859]
content	g.3gpp.cat	Stream associated with the 3GPP Customized Alerting Ringtone (CAT) service	NORMAL	[3GPP TS 24.182 v11.2.0][Frederic_Firmin][RFC8859]
content	g.3gpp.crs	Stream associated with the 3GPP Customized Ringing Signal (CRS) service	NORMAL	[3GPP TS 24.183 v9.10.0 annex E][Frederic_Firmin][RFC8859]
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

[RFC5888][RFC8859]

Available Formats

CSV

Semantics	Token	Mux Category	Reference
Lip Synchronization	LS	NORMAL	[RFC5888][RFC8859]
Flow Identification	FID	NORMAL	[RFC5888][RFC8859]
Single Reservation flow	SRF	NORMAL	[RFC3524][RFC8859]
Alternative Network Address Types	ANAT	CAUTION	[RFC4091][RFC8859]
Forward Error Correction (Deprecated)	FEC	NORMAL	[RFC5956][RFC8859]
Forward Error Correction FR	FEC-FR	NORMAL	[RFC5956][RFC8859]
Composite Session	CS	NORMAL	[RFC-mehta-rmt-flute-sdp-05][RFC8859]
Decoding Dependency	DDP	NORMAL	[RFC5583][RFC8859]
Duplication	DUP	NORMAL	[RFC7104][RFC8859]
Splice	SPLICE	TBD	[RFC8286][RFC8859]
Media bundling	BUNDLE	NORMAL	[RFC9143]
CLUE-controlled "m=" line	CLUE	NORMAL	[RFC8848]

"rtcp-fb" Attribute Values

Registration Procedure(s)

First Come First Served with permanent, stable, and publically accessible document.

Reference

[RFC4585][RFC8859]

Available Formats

CSV

Value Name	Long Name	Mux Category	Reference
ack	Positive acknowledgement	IDENTICAL-PER-PT	[RFC4585][RFC8859]
app	Application-defined parameter	SPECIAL	[RFC4585][RFC8859]
ccm	Codec Control Commands and Indications	IDENTICAL-PER-PT	[RFC5104][RFC8859]
nack	Negative Acknowledgement	IDENTICAL-PER-PT	[RFC4585][RFC8859]
trr-int	Minimal receiver report interval	IDENTICAL-PER-PT	[RFC4585][RFC8859]
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

[RFC4585][RFC8859]

Available Formats

CSV

Value Name	Long Name	Usable with	Mux	Reference
sli	Slice Loss Indication	nack	IDENTICAL-PER-PT	[RFC4585][RFC8859]
pli	Picture Loss Indication	nack	IDENTICAL-PER-PT	[RFC4585][RFC8859]
rpsi	Reference Picture Selection Indication	ack, nack	IDENTICAL-PER-PT	[RFC4585][RFC8859]
app	Application layer feedback	ack, nack	SPECIAL	[RFC4585][RFC8859]
rai	Rapid Acquisition Indication	nack	IDENTICAL-PER-PT	[RFC6285][RFC8859]
tllei	Transport-Layer Third-Party Loss Early Indication	nack	IDENTICAL-PER-PT	[RFC6642][RFC8859]
pslei	Payload-Specific Third-Party Loss Early Indication	nack	IDENTICAL-PER-PT	[RFC6642][RFC8859]
ecn	Explicit Congestion Notification	nack	IDENTICAL	[RFC6679][RFC8859]
ccfb	Congestion Control Feedback	ack	IDENTICAL-PER-PT	[RFC8888]

"depend" SDP Attribute Values

Registration Procedure(s)

Specification Required

Expert(s)

Stephan Wenger

Reference

[RFC5583][RFC8859]

Available Formats

CSV

Token	Semantics	Mux Category	Reference
lay	Layered decoding dependency	IDENTICAL-PER-PT	[RFC5583][RFC8859]
mdc	Multi descriptive decoding dependency	IDENTICAL-PER-PT	[RFC5583][RFC8859]

"cs-correlation" Attribute Values

Registration Procedure(s)

Specification Required

Expert(s)

Bo Burman

Reference

[RFC7195][RFC8859]

Available Formats

CSV

Value	Description	Mux Category	Reference
callerid	Caller ID	TBD	[RFC7195][RFC8859]
uuie	User-User Information Element	TBD	[RFC7195][RFC8859]
dtmf	Dual-tone Multi-Frequency	TBD	[RFC7195][RFC8859]
external	External	TBD	[RFC7195][RFC8859]

Semantics for the "ssrc-group" SDP Attribute

Registration Procedure(s)

Standards Action

Reference

[RFC5576][RFC8859]

Available Formats

CSV

Token	Semantics	Mux Category	Reference
FID	Flow Identification	NORMAL	[RFC5576][RFC8859]
FEC	Forward Error Correction	NORMAL	[RFC5576][RFC8859]
FEC-FR	Forward Error Correction FR	NORMAL	[RFC5956][RFC8859]
DUP	Duplication	NORMAL	[RFC7104][RFC8859]

SDP/RTSP key management protocol identifiers

Registration Procedure(s)

Specification Required

Expert(s)

Magnus Westerlund

Reference

[RFC4567][RFC8859]

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

CSV

Value Name	Long Name	Mux Category	Reference
mikey	Multimedia Internet KEYing	IDENTICAL	[RFC4567][RFC8859]

Codec Control Messages

Registration Procedure(s)

Specification Required

Expert(s)

Stephan Wenger

Reference

[RFC5104][RFC8859]

Available Formats

CSV

Value Name	Long Name	Usable with	Mux	Reference
fir	Full Intra Request Command	ccm	IDENTICAL-PER-PT	[RFC5104][RFC8859]
tmmbr	Temporary Maximum Media Stream Bit Rate	ccm	IDENTICAL-PER-PT	[RFC5104][RFC8859]
tstr	Temporal-Spatial Trade-off	ccm	IDENTICAL-PER-PT	[RFC5104][RFC8859]
vbcm	H.271 video back channel messages	ccm	IDENTICAL-PER-PT	[RFC5104][RFC8859]
pause	Media Pause/Resume	ccm	TBD	[RFC7728][RFC8859]
lrr	Layer Refresh Request Command	ccm	IDENTICAL-PER-PT	[RFC-ietf-avtext-lrr-07]

QoS Mechanism Tokens

Registration Procedure(s)

Specification Required

Expert(s)

Christer Holmberg

Reference

[RFC5432][RFC8859]

Available Formats

CSV

QoS Mechanism	Mux Category	Reference
rsvp	TRANSPORT	[RFC5432][RFC8859]
nsis	TRANSPORT	[RFC5432][RFC8859]

SDP Capability Negotiation Option Tags

Registration Procedure(s)

IETF Review

Reference

[RFC5939][RFC8859]

Available Formats

CSV

Option Tag	Mux Category	Reference
cap-v0	NORMAL	[RFC5939][RFC8859]
med-v0	NORMAL	[RFC6871][RFC8859]
bcap-v0	NORMAL	[RFC7006][RFC8859]
ccap-v0	NORMAL	[RFC7006][RFC8859]
icap-v0	NORMAL	[RFC7006][RFC8859]

SDP Capability Negotiation Configuration Parameters Registry

Registration Procedure(s)

IETF Review

Reference

[RFC5939][RFC6871]

Available Formats

CSV

Encoding Name	Descriptive Name	Potential Configuration Definition	Actual Configuration Definition	Latent Configuration Definition
a	Attribute Configuration	[RFC5939]	[RFC5939]	[RFC6871]
b	Bandwidth	[RFC7006]	[RFC7006]	[RFC7006]
c	Connection Data	[RFC7006]	[RFC7006]	[RFC7006]
i	Title	[RFC7006]	[RFC7006]	[RFC7006]
m	Media Configuration	[RFC6871]	[RFC6871]	[RFC6871]
mt	Media Type	[RFC6871]	[RFC6871]	[RFC6871]
pt	Payload Type Number Mapping	[RFC6871]	[RFC6871]	[RFC6871]
t	Transport Protocol Configuration	[RFC5939]	[RFC5939]	[RFC6871]

Timestamp Reference Clock Source Parameters

Registration Procedure(s)

Specification Required

Expert(s)

Magnus Westerlund

Reference

[RFC7273][RFC8859]

Available Formats

CSV

Name	Long Name	Mux Category	Reference
ntp	Network Time Protocol	NORMAL	[RFC7273, section 4][RFC8859]
ptp	Precision Time Protocol	NORMAL	[RFC7273, section 4][RFC8859]
gps	Global Positioning System	NORMAL	[RFC7273, section 4][RFC8859]
gal	Galileo	NORMAL	[RFC7273, section 4][RFC8859]
glonass	Global Navigation Satellite System	NORMAL	[RFC7273, section 4][RFC8859]
local	Local Clock	NORMAL	[RFC7273, section 4][RFC8859]
private	Private Clock	NORMAL	[RFC7273, section 4][RFC8859]

Media Clock Source Parameters

Registration Procedure(s)

Specification Required

Expert(s)

Magnus Westerlund

Reference

[RFC7273][RFC8859]

Available Formats

CSV

Name	Long Name	Mux Category	Reference
sender	Asynchronously Generated Media Clock	NORMAL	[RFC7273, section 5][RFC8859]
direct	Direct-Referenced Media Clock	NORMAL	[RFC7273, section 5][RFC8859]
IEEE1722	IEEE1722 Media Stream Identifier	NORMAL	[RFC7273, section 5][RFC8859]

Multiplexing Categories

Registration Procedure(s)

Standards Action

Reference

[RFC8859]

Available Formats

CSV

Multiplexing Categories	Reference
NORMAL	[RFC8859]
CAUTION	[RFC8859]
IDENTICAL	[RFC8859]
TRANSPORT	[RFC8859]
SUM	[RFC8859]
INHERIT	[RFC8859]
IDENTICAL-PER-PT	[RFC8859]
SPECIAL	[RFC8859]
TBD	[RFC8859]

association-usage Name Registry

Registration Procedure(s)

First Come First Served

Reference

[RFC8841]

Available Formats

CSV

Name	Reference	Change Controller
webrtc-datachannel	[RFC8841][RFC8832]	IESG

RID Attribute Parameters

Registration Procedure(s)

Specification Required

Expert(s)

Adam Roach

Reference

[RFC8851]

Available Formats

CSV

RID Parameter Name	Reference
pt	[RFC8851]
max-width	[RFC8851]
max-height	[RFC8851]
max-fps	[RFC8851]
max-fs	[RFC8851]
max-br	[RFC8851]
max-pps	[RFC8851]
max-bpp	[RFC8851]
depend	[RFC8851]

Candidate Attribute Extensions

Registration Procedure(s)

Specification Required

Expert(s)

Christer Holmberg

Reference

[RFC8839]

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
[Felix_Poulin]	Felix Poulin, EBU-FNS Coordinator	mailto:poulin&ebu.ch	2016-11-17
[Frederic_Firmin]	Frederic Firmin	mailto:frederic.firmin&etsi.org	2020-09-04
[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 [RFC2198]