五、连接类型 OSI协议集原是面向连接的,但OSI每一层提供的服务既可以是面向连接的,也可以是无连接的。在面向连接的三步操作(建立连接、传送数据和释放连接)中,两个系统之间是直接绑定的。在面向连接的传送中,也可以采用分组方式。在无连接操作中,没有这种明显的链接。在两个通信系统之间传送数据时不执行特定的连接和断开功能。无连接通信也叫做数据报(datagram)通信。 Fifth, the type of connection OSI protocol set was originally for the connection, but OSI provides services at each level can be either connection-oriented, it can be connectionless. In a three-step connection-oriented operation (making a connection, sending data, and releasing a connection), the two systems are bound directly. In connection-oriented delivery, grouping can also be used. In the connectionless operation, there is no such obvious link. When transferring data between two communication systems, no specific connection and disconnection functions are performed. Connectionless communication is also called datagram communication.