摘要： 考虑实时消息的优先级顺序，对光纤通道仲裁环结构下研究实时性问题的“最差情形”做了补充和完善。重新定义保证数据传输实时性的2个限制条件，提出最差情形公平负载率的概念，从而将上述2个限制条件归结为一条，即要保证所有消息的实时性，必须使每个消息的最差情形公平负载率小于等于1，揭示数据传输的实时性与网络负载率之间的本质联系。考虑对实时消息进行拆分后增加的协议开销和物理层延时等影响因素，基于网络总负载率最小化原则给出一种简洁的带宽分配方法。通过实例仿真研究了仲裁环下假想消息集中的各个实时消息在“最差情形”下的带宽分配情况，证明该算法的正确性。

关键词: 实时, 光纤通道, 仲裁环

Abstract: The worst case for real-time transmission on Fibre Channel-Arbitrated Loop(FC-AL) is complemented when considering the priorities of messages. Two conditions to guarantee the deadlines of each message in the message set are re-defined. The concept of the fairness load rate under the worst case is presented so that the above two conditions can be concluded as: the fairness load rate of each message under the worst case should not be greater than 1. This conclusion exposes the essential relationship between the real-time transmission and load rate. Thinking about the increasing cost of protocols and the delay of physical layer due to the segmentation of messages, a dedicated algorithm of bandwidth allocation based on the principle to minimize the total load rate of the network is given. A synthetic message set is studied to prove the validity of this method.

Key words: real-time, Fibre Channel(FC), Arbitrated Loop(AL)

中图分类号: 

• TP393