초록 ▼

A local area network for interconnecting terminals and other users and data processing systems and other service providers over a communications link. The users and providers connect to the communications link by means of interface units each of which may connect to several users or providers. The i

A local area network for interconnecting terminals and other users and data processing systems and other service providers over a communications link. The users and providers connect to the communications link by means of interface units each of which may connect to several users or providers. The interface units communicate over the communications link by means of messages. When a user requires the use of a service, the interface unit establishes a virtual circuit between it and the interface unit connected to the service provider and a service session which allows the user and the service provider to communicate over the virtual circuit. If several users connected to the one interface unit as the first user require services provided by providers which connected to the same interface unit as the first provider, they communicate in sessions over the same virtual circuits. The session messages are accumulated into single virtual circuit messages that are acknowledged in unison by the receiving interface unit. Each virtual circuit in the users\interface units includes a timer which reset when a message is transmitted over the virtual circuit and a data waiting flag set whenever data is present to be transmitted over the virtual circuit. The interface units are inhibited for transmitting over a virtual circuit unless the timer has timed out and the data waiting flag is set.

대표청구항 ▼

A node (34) for transmitting outgoing messages to, and receiving incoming messages from, a local area network (10), said node (34) comprising: A. data storage means (68) for storing data awaiting transmission to said network; B. message transmission means (62, 64) connected to said data storage mean

A node (34) for transmitting outgoing messages to, and receiving incoming messages from, a local area network (10), said node (34) comprising: A. data storage means (68) for storing data awaiting transmission to said network; B. message transmission means (62, 64) connected to said data storage means (68) for transmitting outgoing messages to said network (10), each outgoing message including a data field (140) which may be empty or may contain data obtained from the data storage means (68), and each outgoing message further including a response requested flag field (80) having a value indicating whether or not said node requires a response to a last sent message; C. message receiving means (62, 64, 68) for receiving incoming messages from the network, and for enabling, in response to the receipt of an incoming message from the network, said message transmission means (62, 64) to transmit one outgoing message to said network, wherein said one outgoing message includes any data awaiting transmission in said data storage means (68); D. transmission enabling means (64, 68), for setting said value of said response requested flag field to indicate whether or not said node requires a response to said last sent message, and to set said response requested flag field to a clear value when an outgoing message does not include data.