| Summary: | 碩士 === 國立台灣工業技術學院 === 管理技術研究所 === 85 === Integrated Service Internet running real-time and multimedia
applications is rapidly becoming a reality. Meanwhile, ATM
technology is appearing in the marketplace. It is an important
problem to integrate ATM networks into this Integrated Service
Internet. One of the approaches, classical IP over ATM, is now
widely deployed, effectively solving the problem of
internetworking and interoperability. A key remaining issue is
to provide the QoS guarantees for Internet traffic running
through ATM subnets. This thesis describes a priority scheme,
named User Priority, for providing IP Integrated Service with
quality-of-service over ATM switched virtual circuits (SVCs) to
get better performance of packet delivery.
Define the User Priority field as a three-bit field which uses
Type of Service (TOS) field in the IP datagram header. This
yields 8 different service classes with value 7 = highest
priority and 0 = lowest priority. Class 6 and Class 7 services
are for real-time traffics and have their own VCs. Packets with
Class 0 through 5 are sent on aggregate VC. This method allows
packets to be treated differently according to their priorities
such that they can enjoy the various QoS guarantees provided by
ATM networks.This method is backward compatible with existing IP
implementation. These newer options need only be implemented on
the end systems that want to take advantage of them.
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