综合业务城域网IEEE802.5预约级协议改进策略

THE STRATEGY OF USING IEEE802.5 RESERVING PROTOCOL IN THE METROPOLITAN AREA NET OF INTEGRATED SERVICE

预约是局域网(LAN)中常见的存取方式,尤其以环形LAN的IEEE802.5预约级协议著称。为了在综合业务的环形城域网(MAN)中利用预约级协议,必须考虑综合业务的特点,对IEEE802.5预约级协议进行改进。其出发点是既要尽可能保证高优先级信息能提前预约,又要防止出现低优先级信息(特别是最低优先级信息)长时间得不到发送的局面。该文提出的“高预约级中断策略”,比较合理地解决了这一问题。其实质是在合理范围内牺牲高优先级业务的服务质量,换来部分提高低优先级业务的服务质量。模拟实验表明,改进后的IEEE802.5预约级策略适合于综合业务MAN的利用。

Reservation is frequently used in the local area network(LAN). One of the most famous application is IEEE802.5 reservation protocol. In order to make use of the reservation protocol in the annular MAN, it is necessary to pay more attention to the characteristics of the integrated services. Their purpose is not only assuring the high rank information can reserve token in ahead but also preventing the low rank information (especially the lowest rank information)waiting for a long time. This paper proposes 'high reservation rank interrupt protocol' which can solve the problem rationally. The motif is properly enhancing QoS(Quality of Service) for the low rank information at the cost of the decrease of QoS for the high one. Simulation results show that the improved IEEE802.5 reservation protocol is adapt to MAN which has integrated service.