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Thực hiện tiếng nói qua IP (P6)

VoIP DEPLOYMENT IN ENTERPRISES1 Enterprises are probably the first ones to derive the benefits of running realtime telephony and associated services over an IP network. Before the advent of VoIP, enterprises generally had phone lines for real-time voice and fax services, and a data network based on dial-up, X.25, frame relay (FR), ATM, IP, and so on for data communications services [1]. IEEE standard 802.3 protocol or Ethernet-based LANs are very common in enterprises [2] for data communications networking. . | Implementing Voice over IP. Bhumip Khasnabish Copyright 2003 John Wiley Sons Inc. ISBN 0-471-21666-6 6 VoIP DEPLOYMENT IN ENTERPRISES1 Enterprises are probably the first ones to derive the benefits of running realtime telephony and associated services over an IP network. Before the advent of VoIP enterprises generally had phone lines for real-time voice and fax services and a data network based on dial-up X.25 frame relay FR ATM IP and so on for data communications services 1 . IEEE standard 802.3 protocol or Ethernet-based LANs are very common in enterprises 2 for data communications networking. Small medium-sized and large enterprises can be defined as follows The small office home office SOHO usually supports a few fewer than eight phone lines and a small fewer than 16 ports LAN. Small enterprises commonly support a few fewer than 16 phone lines and a small LAN about 32 ports . They are usually confined to one to four geographical locations. Medium-sized enterprises usually need tens of phone lines a router and multiple medium-sized LAN of 32 to 64 ports Ethernet switch-based LANs per location. Typically they consist of a few offices in multiple geographical locations. Large national enterprises usually need tens to hundreds of phone lines and multiple large Ethernet switch- and router-based LANs per location. Typically they consist of tens of offices in multiple geographical locations. i The ideas and viewpoints presented here belong solely to Bhumip Khasnabish Massachusetts USA. 68 IP-BASED ENDPOINTS DESKTOP AND CONFERENCE PHONES 69 The introduction of VoIP in enterprises not only leads to convergence of multiple disparate networks in one physical infrastructure running only one i.e. IP protocol it also opens up the network for delivering several new and emerging productivity-enhancing IP-based applications and services to the employees and customers of the enterprises. These new services include IP-based fax and conferencing services unified messaging find-me