| 摘要 |
A system for controlling access and transmission timing of communication in a repeating sequence over a network between nodes of one or more terminals, such as in a local area network. Each node in the network is equipped to recognize the presence of boundaries in the transmissions of messages by all nodes in the network. Each node is assigned a place in the list of all the nodes on the network and is controlled by a local timing system to be able to transmit over the network only after the node next preceding it in the list has transmitted. This recognition is accomplished by counting the message boundaries on the network and comparing the count against the list of nodes in the network. Each node will transmit during its time a message of variable length, up to a maximum, but never lass than a minimum that identifies its presence in the network. The system has the capability to recognize a missing node and a jammed network by timing the intervals between messages and comparing these against the maximum allowable transmission times. The system utilizes a very small minimum transmission time so that great efficiency is achieved. The intervals between node transmission time is set to be just larger than the maximum predictable network delays. This achieves predictability in network operation that allows each node to use internally generated timing to identify the cyclical network operation, while achieving high efficiency in network operation and accommodating real time transmission needs. |
