Patent ID: 7730508

Claim:
A data transport device for transporting a data stream, the device comprising: a data stream processing unit for receiving an input data stream comprising a plurality of data packets, each data packet including a continuity count field storing a serial number indicative of packet order in the data stream, performing processing in dependence on the content of the data packets and forming an output data stream comprising at least some of the data packets; and a data packet injection unit comprising: a memory configured to store a plurality of entries, wherein each stored entry comprises: an injection data packet; and an injection action associated with the injection data packet, and an injection processor arranged to retrieve the injection action and associated injection data packet from the entry in memory and, in turn and in dependence on the retrieved injection action, to inject the associated injection data packet into the output data stream of data packets, the injection data packet having a continuity count field and the injection processor including in the continuity count field a serial number consistent with serial numbers in the continuity count fields of the data packets within the output data stream at an injected location of the injection data packet.