计算机会议流控制通道协议研究

RESEARCH ON A CONTROL CHANNEL PROTOCOL FOR THE CONFERENCING STREAM

目前同步计算机会议系统控制方面的能力有限，本文提出一种会议控制协议，基于开放分布式处理参考模型（RM-ODP）控制通道概念，在分析协议需求的基础上，设计了一种组合域名协议原语，并用于协议的形式化描述；同时采用带时间和控制的有色Petri网描述了控制协议实体以进行协议的验证．文章最后简述该协议的设计和实现．

The abilities on session and floor controls are very limited in the previ-ous synchronous computer conference systems. This paper presents a new schemeintended for describing conference control, which is based upon the concept ofstream control channel under open distributed process reference model and called asthe conference stream control channel protocol(CSCCP). In this paper, the tasks ofconference control and the shortcomings of existing systems are discussed,require-ments of CSCCP are also analyzed. Then a kind of protocol description primitiveused to formalize the protocol is proposed as domain naming combination. Usingthis primitive, we can abstract to manage a loosely coupled distributed system inthe Internet, which can scale to as many parties as we want by the IP multicastgroups, The advantage of this primitive is to transfer a conference control protocolwritten by it to a model of Petri net, so that the protocol could be verified. The pa-per defines an advantaged Petri net with time and control parameters used to de-scribe a conferencing system. Some semantic rules of CSCCP, such as naming ser-vice, reliability rules and managing rules of dynamic parties, are also given in thepaper. Finally the implementation of this protocol and an example of a voice con-trolled video conferences are provided.