ATM cell rate control with transmission priority given to control cells for quick response to network congestion

摘要

In an asynchronous transfer mode switched network, a source terminal sends a burst of data cells and a control cell at periodic intervals through network nodes to a destination terminal. Each network node includes a first buffer and a second buffer, and incoming data cells are stored into the first buffer and incoming control cells are stored into the second buffer. A transmit controller is connected to the first and second buffers for forwarding cells in the first and second buffers in a downstream direction with priority given to the control cells in the second buffer over the data cells in the first buffer. A congestion detector is connected to the first buffer for writing a congestion indication into a control cell which is either stored in or forwarded from the second buffer when the first buffer is filled to a predetermined storage level. The destination terminal copies the congestion indication on receiving a control cell from the network and returns a control cell that contains the copied congestion indication toward the source terminal. On receiving a control cell containing the copied congestion indication, the source terminal reduces the data cell transmission rate.