A system, comprising: a source communication device comprising: a first memory to store instructions; and a first processor to execute the instructions to implement: a source network clock to control timing of events associated with communicating with other devices in a network; a source streaming clock associated with processing of audio or video data; a time stamp generator to generate a time stamp that includes a source network clock value derived from the source network clock and a source streaming clock value derived from the source streaming clock; and a time stamp insertion mechanism that incorporates the time stamp into a data unit; and a communication interface to transmit the data unit to one of the other devices in the network; and a sink communication device comprising: a second memory to store instructions; and a second processor to execute the instruction to: the system being characterised in that the second processor is to execute the instructions to: receive the time stamp from the source communication device; compare a sink streaming clock value derived from a sink streaming clock with the source streaming clock value included in the time stamp; and adjust the sink streaming clock based on the comparison. a source communication device comprising: a first memory to store instructions; and a first processor to execute the instructions to implement: a source network clock to control timing of events associated with communicating with other devices in a network; a source streaming clock associated with processing of audio or video data; a time stamp generator to generate a time stamp that includes a source network clock value derived from the source network clock and a source streaming clock value derived from the source streaming clock; and a time stamp insertion mechanism that incorporates the time stamp into a data unit; and a communication interface to transmit the data unit to one of the other devices in the network; and a first memory to store instructions; and a first processor to execute the instructions to implement: a source network clock to control timing of events associated with communicating with other devices in a network; a source streaming clock associated with processing of audio or video data; a time stamp generator to generate a time stamp that includes a source network clock value derived from the source network clock and a source streaming clock value derived from the source streaming clock; and a time stamp insertion mechanism that incorporates the time stamp into a data unit; and a communication interface to transmit the data unit to one of the other devices in the network; and a source network clock to control timing of events associated with communicating with other devices in a network; a source streaming clock associated with processing of audio or video data; a time stamp generator to generate a time stamp that includes a source network clock value derived from the source network clock and a source streaming clock value derived from the source streaming clock; and a time stamp insertion mechanism that incorporates the time stamp into a data unit; and a communication interface to transmit the data unit to one of the other devices in the network; and a sink communication device comprising: a second memory to store instructions; and a second processor to execute the instruction to: the system being characterised in that the second processor is to execute the instructions to: receive the time stamp from the source communication device; compare a sink streaming clock value derived from a sink streaming clock with the source streaming clock value included in the time stamp; and adjust the sink streaming clock based on the comparison. a second memory to store instructions; and a second processor to execute the instruction to: the system being characterised in that the second processor is to execute the instructions to: receive the time stamp from the source communication device; compare a sink streaming clock value derived from a sink streaming clock with the source streaming clock value included in the time stamp; and adjust the sink streaming clock based on the comparison. the system being characterised in that the second processor is to execute the instructions to: receive the time stamp from the source communication device; compare a sink streaming clock value derived from a sink streaming clock with the source streaming clock value included in the time stamp; and adjust the sink streaming clock based on the comparison.