System and method for controlling data transmission between network

Abstract

A system and method for controlling data transmission between two network elements. A first port of a transmitting element is coupled to a second port of a receiving element. The second port includes buffers for temporarily storing received data until the data can be sent to another element. Included in the transmitting element are a received-currently-full register (RCFR), a sent-and-not-received register (SANRR), and a buffer-busy register (BBR). The transmitting element checks its BBR to determine if a buffer in the receiving element is available. The availability of buffers can be determined using a single priority protocol or a multiple priority protocol. If a buffer is available, the transmitting element transmits a data frame to the receiving element and sets the SANRR and the BBR to indicate that a frame has been sent (and that no acknowledgment has been received), that the selected buffer in the receiver is full, and that no additional data frames are to be sent to this buffer until the buffer is empty. When data is received by the receiving element, it is sent to an available buffer. When the data is received by the buffer, the receiving element sets a bit in a currently-full register (CFR) and a bit in a next-message-to-send register (NMTSR). A control signal is transmitted by the data receiving element on the same signal line as data that is being sent from the data receiving element to the data transmitting element. The data receiving element can multiplex the frames being sent in this direction with the control signal. When the transmitting element receives the control signal, it resets a bit associated with a buffer in the SANRR if the bit is set in the SANRR and if the associated bit in the NMTSR portion of the control signal is set.