Network control system with improved reliability

摘要

A timer manager for use in a network control system of one node of a connectionless communication network provides message receipt reliability. The network control system includes a buffer pool for storing messages to be transmitted from the one node and a data link stage for receiving the buffer pool storage address of a message to be transmitted and causing the message to be accessed and transmitted onto the bus. The timer manager is coupled to the buffer pool and to the data link stage and includes a table including a plurality of entry slots for storing the buffer pool storage address of a message to be transmitted with an associated timer entry index. The timer manager is responsive to an add timer request of the data link stage for locating an available entry slot in the table for a message to be transmitted, obtains the buffer pool storage address of the message from the data link stage, stores the buffer pool storage address in the entry slot, and conveys to the data link stage the index of the entry slot. The timer manager further includes a timer associated with the entry slot and starts the timer responsive to the message being transmitted onto the bus. The timer manager is arranged to convey to the data link stage a time-out message if the timer times a predetermined time period without receiving a receipt acknowledgement.