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PHILOSOPHY |
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"New World" - a relative of Internet protocols - simple, open and horizontal |
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"Old World" - complex, deterministic and vertical |
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IETF |
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ITU |
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Carrier-class solution addressing the wide area |
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Borne of the LAN - focusing on enterprise conferencing priorities |
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CHARACTERISTICS |
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A simple toolkit upon which smart clients and applications can be built. It re-uses Net elements (URLs, MIME and DNS) |
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H.323 specifies everything including the codec for the media and how you carry the packets in RTP |
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Leaves issues of reliability to underlying network |
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Assumes fallibility of network - an unnecessary overhead |
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SIP messages are formatted as text. (Text processing lies behind the web and email) |
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Binary format doesn't sit well with the internet - this adds complexity |
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SIP allows for standards-based extensions to perform specific functions. |
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Extensions are added by using vendor-specific non-standard elements |
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Hierarchical URL style addressing scheme that scales |
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Addressing scheme doesn't scale well |
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Minimal delay - simplified signalling scheme makes it faster |
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Possibilities of delay (up to 7 or 8 seconds!) |
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Slim and Pragmatic |
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The suite is too cumbersome to deploy easily |
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SERVICES |
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Standard IP Centrex services |
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Standard IP Centrex services |
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Ability to 'fork' calls |
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Not possible in the existing standard |
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User profiling |
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- |
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'Unified messaging' |
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- |
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Presence management |
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- |
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Unique ability to mix media (e.g. IVR) |
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Cannot mix media within a session |
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URLs can be embedded in web browsers and email tools |
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H.323 has no URL format |
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Works smoothly with media gateway controllers controlling multiple gateways - crucial in a multi-operator environment |
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"Shoehorn" interworking with SS7 is problematic - H.323 has trouble connecting calls to and from PSTN endpoints |
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Seamless interaction with other media - services are only limited by the developers imagination |
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Services are nailed-down and constricted - voice only ceiling |
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STATUS |
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Industry endorsed |
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Popularity due to the fact that it was the first set of agreed-upon standards |
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Many vendors developing products |
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The majority of existing IP telephony products rely on the H.323 suite |