A system for performing packet based data communications over a parallel set of sublinks is provided. A transmitter unit separates the sublinks into an available set of sublinks and a busy set of sublinks. This transmitter avoids processing delays by utilizing sublinks in the available sublink set and not waiting for sublinks in the busy sublink set to be released. To receive the packets, a receiver unit utilizes a sequence number associated with each packet. Accordingly, the receiver extracts the one or more packets of data received in parallel over the set of sublinks in sequential order. A packet window buffer is used to store packets in sequence if they are initially received out of order. The receiver utilizes a sliding window to provide packets in continuous sequential order and transmits the packets serially over a single communication link.