Abstract: In an arrangement located between input and output paths to carry out a broadcast operation, an input virtual channel identifier (VCI; is included in an asynchronous transfer mode (ATM) cell and given to a selected one of parameter production elements to access a conversion table connected to the selected parameter production element and to read a specific intermediate conversion parameter indicative of the broadcast operation out of the conversion table. The specific intermediate conversion parameter is sent to a first switch together with the ATM cell and to a second switch to be delivered to a plurality of the output paths. On the plurality of the output paths, the specific intermediate conversion parameters are converted into output VCI's which are different from and independent of one another. Thus, the broadcast operation is favorably carried out in the arrangement.

Abstract: A fair and efficient admission scheme enables sharing of a common resource among N traffic classes, such that each class is guaranteed (on a suitable long-term basis) a contracted minimum use of the resource, and each class can go beyond the contract when extra resource capacity becomes temporarily available. The scheme operates in an open loop mode, and thus does not require information describing the current status of the resource. For the purposes of description, one form of the invention is best described in terms of "tokens" and "token banks" with finite sizes. Our scheme uses one token bank per class (bank `i`, i= 1, . . . ,N), plus one spare bank. Class `i` is preassigned a rate, rate(i), i=1, . . . ,N, that represents the "guaranteed throughput" or contracted admission rate for class `i`. Tokens are sent to bank `i` at rate(i). Tokens that find a full bank are sent to the spare bank. When the spare bank is also full, the token is lost. Every admitted arrival consumes a token.

Abstract: An apparatus for evaluating data rates of virtual circuits occupying an asynchronous time-multiplexed transmission path includes a memory in which each virtual circuit is allocated space containing a context defining conditions for evaluating the data rate of the virtual circuit. This context contains a starting time which was the current time as recorded on receiving an earlier cell in the virtual circuit under consideration. Each time a cell is received, the context of the virtual circuit to which the cell belongs is read, and the starting time is subtracted from the new current time, with the time difference established in this way constituting the basis on which the data rate is evaluated, and with repressive countermeasures being initiated in the event of the data rate being excessive. The apparatus further includes device for cyclically scanning the contexts and for incrementing a scan cycle counter in each context during the cyclic scanning, the scan cycle counter having an initial position.