Next , synthesizing the features of wired and wireless lan , a network structure based on combination of wired and wireless network is presented as network structure of on - board wirless comminucation system , alone with a discussion of problems on store and forward switching , enrolment of consumer , management of route control . call control and problems of network layer . at one time , design and realization of on - board wireless comminucation system are introduced combined with its feature 其次，分析了有线局域网与无线局域网的特点，提出了一种基于有线无线异构网络作为车载无线数据传输系统的网络结构，讨论了存储转发、用户注册、地址与路由管理和呼叫控制等网络层问题。并结合车载无线数据传输系统的实际特点，具体说明了车载无线数据传输系统的设计与实现过程。
The rapid development of the internet and the low cost of ip communication , have made facsimile over ip ( foip ) an inevitable trend . combining ip technology and facsimile communication , foip fall into real - time foip and store - and - forward foip , which have respective advantages and shortcomings under different circumstances Internet在世界范围内的飞速发展和ip通信低资费的优势，使得ip传真通信成为一种必然的发展趋势。 ip传真通信是ip技术与传真通信技术相融合的产物，可分为实时ip传真和存储转发式ip传真。
This paper provides a discussion on the theory of distributed database , summarize the virtues and flaws of two - phase - commit protocol and replication technology , and then puts forward a synchronous update system model to solve the problems encountered while longkou port was realizing the data share among different kind of databases located in different area . this model , based on 2pc and the mainstream database replicate technology at present , can realize data sharing and data consistency among heterogeneous databases by odbc and tcp / ip technology , and now has been partly implemented 本文在讨论有关分布式数据库理论的基础上，总结了两阶段提交协议和数据库复制技术在异构型分布式数据同步中的优缺点，以龙口港信息系统在实现异构分布式数据库共享过程中遇到的问题为背景，利过odbc和tcp ip技术，对数据库更新事务进行存储转发，进而实现数据同步更新的系统模型，提出了一套网络环境下的分布式数据库同步机制。
