Protocolos VOIP Standards.

Signalling

ITU-T Standards and Recommendations

H.323 V2	Packet-based multimedia communications systems
H.225.0	Call signalling protocols and media stream packetization for packet-based multimedia (includes Q.931 and RAS)
H.225.0 Annex G	Gatekeeper to gatekeeper (inter-domain) communications
H.245	Control protocol for multimedia communications
H.235	Security and encryption for H-series multimedia terminals
H.450.x	Supplementary services for multimedia: 1. Generic functional protocol for the support of supplementary services in H.323 2. Call transfer 3. Diversion 4. Hold 5. Park & pickup 6. Call waiting 7. Message waiting indication
H.323 Annex D	Real-time fax using T.38
H.323 Annex E	Call connection over UDP
H.323 Annex F	Single-use device
T.38	Procedures for real-time group 3 facsimile communications over IP networks
T.120 series	Data protocols for multimendia conferencing

IETF RFCs and Drafts

RFC 2543	SIP: Session initiation protocol
RFC 2327	SDP: Session description protocol
Internet Draft	SAP: Session announcement protocol

Gateway Control

ITU

H.GCP

Proposed recommendations for gateway control protocol

IETF

Internet Draft	MGCP: Media gateway control protocol
Internet Draft	MEGACO protocol
Draft	SGCP: Simple gateway control protocol
Internet Draft	IPDC: IP device control

Media Transport

IETF

RFC 1889	RTP: Real-time transport protocol
RFC 1889	RTCP: Real-time transport control protocol
RFC 2326	RTSP: Real-time streaming protocol

Media Encoding

ITU

Voice

Standard	Algorithm	Bit Rate (Kbit/s)	Typical end-to- end delay (ms) (excluding channel delay)	Resultant Voice Quality
G.711	PCM	48, 56, 64	<<1	Excellent
G.723.1	MPE/ACELP	5.3, 6.3	67-97	Good(6.3), Fair(5.3)
H.728	LD-CELP	16	<<2	Good
G.729	CS-ACELP	8	25-35	Good
G.729 annex A	CS-ACELP	8	25-35	Good
G.722	Sub-band ADPCM	48, 56, 64	<<2	Good
G.726	ADPCM	16,24,32,40	60	Good(40), Fair(24)
G.727	AEDPCM	16, 24, 32, 40	60	Good(40), Fair (24)

Video

Standard	Algorithm	Bit Rate (Kbit/s)	Picture Quality
H.261	Discrete cosine transform (DCT) with motion compensation	px64 (p=# of ISDN B channels)	Low
H.263	Improved version of H.261	Various	Medium