Patent ID: 8009557

Claim:
An apparatus for creating a sub-channel within a main channel between a first network node and a second network node, the apparatus comprising: a communication monitoring apparatus for generating measurement data in relation to a communication link between the first and second network nodes; a data store for temporarily storing sub-channel data comprised of the measurement data; a processing resource for monitoring downstream communication from the first network node, the processing resource being arranged, when in use, to identify a predetermined minimum idle duration in the downstream communication, and to determine whether the predetermined minimum idle duration will occur before the data store overflows, the predetermined minimum idle duration supporting initiation of transmission of the sub-channel data in place of at least part of data for signifying an idle period in the downstream communications; wherein the processing resource is further arranged to transmit upstream, when in use, a flow control message for receipt by the first network node, to cause generation of the predetermined minimum idle duration before the data store overflows; wherein the processing resource is further arranged to drop a packet of the sub-channel data from the data store in order to avoid overflow of the data store if the first network node does not implement flow control to reduce affect on the transmission of the main channel; wherein the processing resource is arranged to identify, when in use, the at least part of the data for signifying the idle period in the downstream communication, and to determine whether a subsequent idle period for the main channel will occur and whether insufficient time exists to await probabilistic occurrence of a subsequent idle period, the subsequent idle period being required when the data for signifying the idle period does not correspond to at least the predetermined minimum idle duration; wherein the generation of the predetermined minimum idle duration occurs at least during part of the subsequent idle period; and wherein the processing resource is arranged to determine whether the data for signifying the idle period exceeds an average duration to support the initiation of transmission of the sub-channel data.