Allocating isochronous channel numbers to devices on an IEEE-1394 bus

Abstract

The isochronous channel number to be used in transferring an isochronous data stream over a bus from a source device to a destination device can be selected via a simple and straightforward method or a low cost apparatus. The device identifier of the source device is obtained. A device identifier suitable in some embodiments of the invention is the node identifier of the source device within an IEEE-1394, IEEE-1394a or an IEEE-1394.B bus. If the source device is not currently outputting another isochronous stream over the bus, then an isochronous channel number that corresponds to (for example, equals) the source device identifier can be used. In some embodiments, each device is entitled to use an isochronous channel number equal to its physical ID and thus need not check to see if that channel is otherwise in use. When multiple isochronous channels are to be output from the same device, then some embodiments use the device identifier of a device to which the isochronous stream is to be transmitted, when the isochronous channel of that number is available. Some embodiments use the highest available channel number below the isochronous channel reserved for broadcasting. Some embodiments listen on the bus for isochronous transmissions to determine that a particular isochronous channel is not currently in use. Some embodiments of the invention are advantageous for situations where the bus is a simple one that does not have an isochronous resource manager.

Dependencies are inferred from the claim text.