| 摘要 |
A facility is provided in an ATM network to control the level of data traffic that a source of data supplies to the network for transmission over an associated connection. Such control is achieved by associating a scout cell with an availability parameter (Ac) and also associating each output port serving a segment of a connection with an availability parameter (Ap) indicative of the level of congestion at the port. Responsive to receipt of a scout cell, an output port overwrites the availability parameter (Ac) contained in the scout cell with its availability parameter (Ap) only if the latter value is less than the former value. The output port then forwards the scout cell to its intended destination. The destination port performs the same function, and then returns the scout cell to its originator via the reverse direction of the connection. Accordingly, the value of the availability parameter Ac contained in a returned scout cell thus indicates whether or not congestion exists at a point along the forward direction of a connection. That is, the value of Ac will be a minimum of all of the port availability parameters (Ap1, Ap2, .... Apn) values that the cell encountered as it traversed the associated connection. The level of such control is then determined as a function of the value of the availability parameter contained in the received scout cell.
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