Packet switching device with a feedback method of the arbiter
View Patent ↗The invention relates to a packet switching device comprising at least one line card ( 1 and 2 ) which device has an output port with a port control ( 6 and 7 ) for storage and arrangement of packets in output queues and for generating at least one feedback information unit to inform an arbiter ( 9 ) of statuses of the output queues of the output port. The packet switching device also comprises at least one switch card ( 3 to 5 ) consisting of a crosspoint matrix and the arbiter ( 9 ) for controlling the crosspoint matrix ( 8 ).
1. A packet switching device having one or more input ports and one or more output ports, the packet switching device providing for switching of one or more data packets among the one or more input ports and the one or more output ports, the packet switching device comprising:
a crosspoint matrix, the crosspoint matrix providing for switching of the one or more data packets as to the one or more input ports and the one or more output ports;
a port control coupled to the crosspoint matrix, the port control having a virtual output queue associated with the one or more output ports and providing status information, the status information including (i) weighting associated with the one or more input ports and (ii) feedback information as to the virtual output queue; and
an arbiter, the arbiter coupled to the port control so as to receive the weighting and feedback information and coupled to the crosspoint matrix so as to provide for configuration of the crosspoint matrix, the arbiter supporting a first status matrix, a second status matrix, and a decision matrix, wherein (a) the first status matrix includes elements, the elements representing the weighting of combinations of each respective one of the one or more input ports with each respective one of the one or more output ports, (b) the second status matrix includes a reduced set of the elements of the first status matrix, the reduced set being determined responsive to the feedback information and the first status matrix, and (c) the decision matrix includes marked combinations representing elements of the second status matrix as determined through switching, wherein the marked combinations providing for configuration of the crosspoint matrix and wherein the arbiter is configured to pass at least one of the marked combinations to at least one of the one or more input ports.
2. A packet switching device as claimed in claim 1 , further comprising a memory for storage and arrangement of the one or more data packets in one or more queues and wherein the port control is configured to provide feedback information in the form of a feedback information unit as to at least one of the one or more queues.
3. A packet switching device as claimed in claim 2 , wherein the port control comprises the memory.
4. A packet switching device as claimed in claim 1 , wherein the port control is configured to provide status information at regular intervals.
5. A packet switching device as claimed in claim 1 , wherein the port control is configured to send data packets to the crosspoint matrix at regular intervals.
6. A packet switching device as claimed in claim 1 , wherein the arbiter is configured to provide for configuration of the crosspoint matrix at regular intervals.
7. A packet switching device as claimed in claim 6 , wherein the arbiter is configured to provide for re-configuration of the crosspoint matrix at regular intervals based on new elements of the first status matrix, such new elements representing the new combinations of each respective one of the one or more input ports with each respective one of the one or more output ports.
8. A packet switching device as claimed in claim 1 , wherein the arbiter is configured to retain feedback information units in a feedback vector.
9. A packet switching device as claimed in claim 1 , wherein the arbiter is configured to send the configuration of the crosspoint matrix to the port control.
10. A packet switching device as claimed in claim 1 , wherein the port control provides the feedback information unit representative of at least the stage of a memory associated with the virtual output queue.
11. A packet switching device as claimed in claim 10 , wherein the arbiter is configured to provide for configuration of the crosspoint switch so that, responsive to the stage representing the memory being full or substantially full, no data packet is switched to the one or more output ports associated with such memory.
12. A packet switching device as claimed in claim 1 , wherein the port control provides the weighting as configured to represent the presence of at least one data packet.
13. A packet switching device as claimed in claim 12 , wherein the port control provides the weighting as configured to represent urgency for switching of the at least one data packet that is present.
14. A packet switching device as claimed in claim 13 , wherein the port control provides the weighting as configured to represent urgency, the urgency reflecting, as to the at least one data packet that is present, either or both of priority or/and class.
15. A packet switching device as claimed in claim 1 , wherein the arbiter is configured such that the decision matrix implements switching through application of a predetermined decision algorithm.
16. A packet switching device as claimed in claim 15 , wherein the arbiter is configured such that the decision matrix implements switching through application of a SIMP algorithm.
17. A packet switching device as claimed in claim 15 , wherein the arbiter is configured such that the decision matrix implements switching responsive to highly weighted combinations.
18. A packet switching device having one or more input ports and one or more output ports, the packet switching device providing for switching of one or more data packets among the one or more input ports and the one or more output ports, the packet switching device comprising:
a crosspoint matrix, the crosspoint matrix providing for switching of the one or more data packets as to the one or more input ports and the one or more output ports;
a port control coupled to the crosspoint matrix, the port control having a virtual output queue associated with the one or more output ports and providing status information, the status information including (i) weighting associated with the one or more input ports and (ii) feedback information as to the virtual output queue; and
an arbiter, the arbiter coupled to the port control so as to receive the weighting and feedback information and coupled to the crosspoint matrix so as to provide for configuration of the crosspoint matrix, the arbiter supporting a first status matrix, a second status matrix, and a decision matrix, wherein (a) the first status matrix includes elements, the elements representing the weighting of combinations of each respective one of the one or more input ports with each respective one of the one or more output ports, (b) the second status matrix includes a reduced set of the elements of the first status matrix, the reduced set being determined responsive to the feedback information and the first status matrix, and (c) the decision matrix includes marked combinations representing elements of the second status matrix as determined through switching, wherein the marked combinations providing for configuration of the crosspoint matrix and wherein the arbiter is configured to send the configuration of the crosspoint matrix to the port control.