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DAV Nguyên tắc và các ứng dụng P12

Two-phase combined QoS-based handoff scheme Wireless Personal Communication Services (PCS) and broadband networking for delivering multimedia information represent two well-established trends in telecommunications. While technologies for PCS and broadband communications have historically been developed independently, harmonization into a single architectural framework is motivated by an emerging need to extend multimedia services to portable terminals. | Mobile Telecommunications Protocols For Data Networks. Anna Hac Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-85056-6 12 Two-phase combined QoS-based handoff scheme Wireless Personal Communication Services PCS and broadband networking for delivering multimedia information represent two well-established trends in telecommunications. While technologies for PCS and broadband communications have historically been developed independently harmonization into a single architectural framework is motivated by an emerging need to extend multimedia services to portable terminals. With the growing acceptance of Asynchronous Transfer Mode ATM as the standard for broadband networking it has become appropriate to consider the feasibility of standard ATM services into next-generation microcellular wireless and PCS scenarios. The use of ATM protocols in both fixed and wireless networks promises the important benefit of seamless multimedia services with end-to-end Quality-of-Service QoS control. The wireless ATM WATM specification provides an option to existing ATM networks that wish to support terminal mobility and radio access while still retaining backward compatibility with ATM equipments. The current developments on WATM are mainly based on ATM as the backbone network with a wireless last-hop extension to the mobile host. Mobility functions are implemented into the ATM switches and the Base Stations BSs . WATM helps to bring multimedia to mobile computers. Compared with the wireless LANs which have a limitation of bandwidth to support multimedia traffic and slow handoff the bandwidth of existing mobile phone systems is sufficient for data and voice but it is still insufficient for real-time multimedia traffic. ATM has more efficient networking technology for integrating services flexible bandwidth allocation and service type selection for a range of applications. The current interest and research efforts are intense enough to claim that WATM will continue to be pursued as a .