order to identify the boundaries between two successive time frames the select buffer and time driven random early discard controller 45 d generates a time frame delimiter tfd signal 47 a to the serial transmitter 49 for transmission on its respective communications link in order to signal the second switch the exact boundary between two time frames each of the data packets is encoded as a stream of data and a time frame delimiter is inserted into the stream of data responsive to the select buffer controller this can be implemented by using redundant serial codewords in a possible operation when a data packet in a generic transmit buffer b j cannot be retrieved and passed to the serial transmitter 49 for transmission on its respective communications link before the end of the respective time frame the select buffer and time driven random early discard controller 45 d can be moved back to the best effort scheduling controller 45 a in this mode of operation the best effort scheduling controller 45 a is comprised of a rescheduling controller 45 rc that determines the new one of the transmit buffers 45 c in which the packet should be stored while awaiting for transmission a possible program executed by the best effort scheduling controller 45 a is described in fig1 when a data packet is received from either the fabric via link 51 or from the select buffer and time driven random early discard controller 45 d via link 45 r as specified in 45 03 the 35 c 35 t and 35 p in the data packet header are used to look up the forward parameter 45 f in the forwarding table 45 b as specified in 45 04.