Abstract: A packet switch has a switching unit (SU) for switching packets between network links and a computing unit (CU) connected to the SU through a network link for implementing software control functions over the SU. The SU is formed of different functional components interconnected by generic buses. The components communicate with one another using program data units (PDUs) that are formatted and transmitted according to a shared device protocol. The communication between the components occurs by placing PDUs in bus frames that are passed from component to component. Information is exchanged between the components by adding information to or dropping information from the fields of the PDUs, or by concatenating new fields to the PDUs, as the frames pass from component to component. By using a generic bus to implement PDU-based interconnections within the SU, all the components are forced to support a common interface.

Abstract: A scheduling apparatus, that can be used within a supertrunking capable Internet Protocol (IP) Forwarding (IPF) node, allows for efficient scheduling of packets for servicing after the packets are sorted into their proper order. The scheduling apparatus has a point and serve mechanism, a round-robin mechanism, and a starvation mechanism, and is to be used in situations where an IPF node is sorting and outputting multiple numbers of data streams. The point and serve mechanism directs two supertrunk pointers to the front packets of the particular data streams that the incoming packet segments correspond. The round-robin mechanism rotates a round-robin pointer between the front packets corresponding to all the different data streams. The starvation mechanism flags a data stream as starving if no packets have been scheduled after a predetermined number of times in which the round-robin pointer has been directed at the particular stream.