Voice over IP
Tutorial
Part I VoIP Scenarios - Video and
Audio Compression |
Contents:
VoIP scenarios: classical telecommunications networks, separate
data and voice networks versus unified networks, migration path to VoIP,
least cost routing - today and tomorrow, VoIP - pro and contra, Overview
of the H.323 multimedia communication standard. Video compression:
H.261 / H.262 and H.263 DCT-based compression algorithms, macroblock based
encoding of color information, motion vector estimation, group of pictures
difference coding scheme, video conferencing picture formats. Audio
compression: G.711 pulse code modulation @ 64 kbit/s, G.722 adaptive
differential pulse code modulation @ 64/32 kbit/s, linear prediction coder
@ 2.5 kbit/s, G.728 code excited linear prediction coder @ 16 kbit/s,
G.729 audio code for frame relay @ 8 kbit/s, GSM 06.10 enhanced full rate
coder @ 13 kbit/s, mean opinion score (MOS). H.32x family: H.320
videoconferencing over ISDN, H.324 videoconferencing over POTS.
Distribution Format:
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Part II The H.323 and SIP Standards |
Contents:
H.323 network components: terminals, gatekeepers, gateways,
multipoint control units. H.323 gateway: gateway to PSTN, protocol
translation, audio/video transcoding. H.323 gatekeeper: H.323
zones, automatic gatekeeper discovery, endpoint registration,
unregistration, location and admission to network. H.323 call setup and
control: Q.931 call signalling channel (gatekeeper-routed and direct
call setup), H.245 control channel (gatekeeper-routed and direct control),
H.245 capabilities exchange. Channel multiplexing: H.225.0 channel
multiplexing, transport of logical channels over IP-based networks using
UDP and TCP). Multipoint conferences: Multipoint control and
multipoint processor functions for multipoint conferencing, centralized
and decentralized multipoint conferences. Session Initiation Protocol
(SIP): SIP uniform resource locators, SIP invitation using a SIP proxy
server, example of an INVITE request.
Distribution Format:
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