Time-synchronized multi-layer network switch for providing quality of service guarantees in computer networks

• US 6,141,355 A
• Filed: 12/29/1998
• Issued: 10/31/2000
• Est. Priority Date: 11/06/1998
• Status: Expired due to Fees

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Path 1 Network Technologies, Inc.
• Inventors: Cruz, Rene L., Palmer, Douglas A., Fellman, Ronald D.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US09/222,183
• Time in Patent Office: 672 Days
• Field of Search: 370/235, 370/236, 370/237, 370/252, 370/260, 370/261, 370/445, 370/447, 370/464, 370/465, 370/466, 370/467, 370/503, 370/510, 370/512
• US Class Current: 370/465
• CPC Class Codes: H04L 12/6402 Hybrid switching fabrics
• CPC Class Codes: H04L 2012/6454 Random, e.g. Ethernet
• CPC Class Codes: H04L 2012/6459 Multiplexing, e.g. TDMA, CDMA
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

A network system for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including an arbitration mechanism that provides a low cost and high performance mechanism for delivery of quality of service guarantees for time-sensitive data sharing a local area with non-time-sensitive data. Device adapters are placed at all access points to a local network. The device adapters limit admission rates and control the timing of all packets entering the network. An X-Hub placed at the center of the network provides for transparent, concurrent transport of signals transmitted by device adapters. Collisions may therefore be eliminated for time-sensitive traffic, thereby guaranteeing timely delivery. A common time reference is established for the device adapters and the X-Hub. The time reference defines a frame with a plurality of phases. Each of the phases defines a state of the X-Hub, and a state for each of the device adapters. Each device adapter is allowed to transmit packets of data onto the network directly to one or more destination device adapters, without the possibility of collisions, during a phase in which it is in a cross-connect mode. Each device adapter can also broadcast unscheduled transmissions, usinig a conventional network protocol (such as CSMA/CD), when it is not in the cross-connect mode. The scheduling of phases to support transport of signals in the cross-connect mode can be dynamically altered, in accordance with a signaling protocol, based on unscheduled transmissions using the conventional network protocol when the X-Hub is so configured.

Claims

1. A network system for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including:

a switching hub device having a plurality of input ports and a plurality of output ports, for transferring packets between selected input ports to selected output ports for transmission on the network;

at least one device adapter, each configured to be coupled to at least one network device and to at least one of said plurality of input ports and at least one of said plurality of output ports of the switching hub device, for transmitting packets between at least one of the coupled network devices and the switching hub device;

timing synchronization circuitry, coupled to the switching hub device and each device adapter coupled to the switching hub device, for providing common time schedule information to the switching hub device and each such coupled device so as to selectively synchronize transferring of packets by the switching hub device and transmission of packets by each coupled device adapter;

configuration circuitry, coupled to the switching hub device, for periodically setting a configuration of the switching hub device to couple selected pairs of device adapters for direct intercommunication of packets in accordance with such time schedule information during a first time interval.

2. The network system of claim 1, wherein the configuration circuitry configures the switching hub device to operate for a second time interval wherein each device adapter may intercommunicate packets by means of a conventional network protocol.

3. The network system of claim 2, further including at least one network device coupled directly to the switching hub device, wherein each such network device may intercommunicate packets by means of a conventional network protocol during such second time intervals.

4. The network system of claim 1, wherein the configuration circuitry configures the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

5. The network system of claim 1, wherein the configuration circuitry configures the switching hub device during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

6. The network system of claim 2, wherein the configuration circuitry configures the switching hub device during each second time interval to directly couple each input port that is coupled to said at least one device adapter configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to said at least one device adapter similarly configured to intercommunicate packets by means of said conventional network protocol.

7. The network system of claim 2, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

8. The network system of claim 1 wherein the time schedule information is provided through a network link to each device adapter coupled to the switching hub device.

9. A network system for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including:

(a) a switching hub device having input ports and output ports, for transferring packets between selected input ports to selected output ports for transmission on the network;

(b) at least one device adapter, each configured to be coupled to at least one network device and to an input port and an output port of the switching hub device, for transmitting packets between at least one of the coupled network devices and the switching hub device;

(c) timing synchronization circuitry, coupled to the switching hub device and each device adapter coupled to the switching hub device, for providing a common time reference to the switching hub device and each such coupled device so as to selectively synchronize transferring of packets by the switching hub device and transmission of packets by each coupled device adapter;

(d) configuration circuitry, coupled to the switching hub device, for periodically configuring the switching hub device to operate in (1) a first time interval wherein selected pairs of coupled device adapters can directly intercommunicate packets, and (2) a second time interval wherein device adapters may intercommunicate packets by means of a conventional network protocol.

10. The network system of claim 9, further including at least one network device coupled directly to the switching hub device, wherein each such network device may intercommunicate packets by means of said conventional network protocol during the second time interval.

11. The network system of claim 9, wherein the configuration circuitry configures the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

12. The network system of claim 9, wherein the configuration circuitry configures the switching hub device during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

13. The network system of claim 9, wherein the configuration circuitry configures the switching hub device during each second time interval to directly couple each input port that is coupled to one of the at least one device adapter configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to one of the at least one device adapter similarly configured to intercommunicate packets by means of said conventional network protocol.

14. The network system of claim 9, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

15. The network system of claim 9, wherein the time reference includes time schedule information provided through a network link to each device adapter coupled to the switching hub device.

16. A network system for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including:

a switching hub device having a plurality of input ports, a plurality of output ports, and a crossbar switch system coupled to each of the respective pluralities of input ports and output ports for transferring packets between selected ones of the input ports to selected ones of the output ports for transmission on a network;

at least one device adapter, each configured to be coupled to at least one network device and to an input port and an output port of the switching hub device through the network, for transmitting packets on the network between at least one of the coupled network devices and the switching hub device;

timing synchronization circuitry, coupled to the switching hub device and each device adapter coupled to the switching hub device, for providing a common time reference to the switching hub device and each such coupled device so as to selectively synchronize transferring of packets by the switching hub device and transmission of packets by each coupled device adapter;

configuration circuitry, coupled to the switching hub device, for periodically configuring the switching hub device to operate in (1) a first time interval wherein selected pairs of coupled device adapters can directly intercommunicate packets, and (2) a second time interval wherein device adapters may intercommunicate packets by means of a conventional network protocol.

17. The network system of claim 16, further including at least one network device coupled directly to the switching hub device, wherein each such network device may intercommunicate packets by means of said conventional network protocol during second time intervals.

18. The network system of claim 16, wherein the configuration circuitry configures the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

19. The network system of claim 16, wherein the configuration circuitry configures the crossbar switch system during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

20. The network system of claim 16, wherein the configuration circuitry configures the crossbar switch system during each second time interval to directly couple each input port that is coupled to one of the at least one device adapter configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to one of the at least one device adapter similarly configured to intercommunicate packets by means of said conventional network protocol.

21. The network system of claim 16, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

22. The network system of claim 16, wherein the time reference includes time schedule information provided through a network link to each device adapter coupled to the switching hub device.

23. A switching hub device having a plurality of input ports, a plurality of output ports, and a crossbar switch system coupled to each of the respective pluralities of input ports and output ports for transferring packets between selected ones of the input ports to selected ones of the output ports for transmission on a network, the switching hub device being adapted to be coupled to at least two device adapters each for transmitting packets between at least one coupled network device and the switching hub device, the switching hub device and each device adapter being substantially synchronized to a selectable time schedule, the switching hub device including configuration circuitry for periodically setting a configuration of the switching hub device to couple selected pairs of device adapters for direct intercommunication of packets in accordance with such time schedule during a first time interval.

24. The switching hub device of claim 23, wherein the configuration circuitry configures the switching hub device to operate for a second time interval wherein each device adapter may intercommunicate packets by means of a conventional network protocol.

25. The switching hub device of claim 24, further including at least one network device coupled directly to the switching hub device, wherein each such network device may intercommunicate packets by means of the conventional network protocol during such second time intervals.

26. The switching hub device of claim 23, wherein the configuration circuitry configures the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

27. The switching hub device of claim 23, wherein the configuration circuitry configures the crossbar switch system during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

28. The switching hub device of claim 24, wherein the configuration circuitry configures the crossbar switch system during each second time interval to directly couple each input port that is coupled to one of the at least two device adapters configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to one of the at least two device adapters similarly configured to intercommunicate packets by means of said conventional network protocol.

29. The switching hub device of claim 24, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

30. A method for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including the steps of:

providing a switching hub device having a plurality of input ports and a plurality of output ports, for transferring packets between selected input ports to selected output ports for transmission on a network;

providing at least one device adapter, each configured to be coupled to at least one network device and to one of said plurality of input ports and to one of said plurality of output ports of the switching hub device through a network, for transmitting packets on the network between at least one of the coupled network devices and the switching hub device;

selectively synchronizing transferring of packets by the switching hub device and transmission of packets by each coupled device adapter;

periodically setting a configuration of the switching hub device to couple selected pairs of device adapters for direct intercommunication of packets in accordance with selected time schedule information during a first time interval.

31. The method of claim 30, further including the step of periodically configuring the switching hub device to operate for a second time interval wherein each device adapter may intercommunicate packets by means of a conventional network protocol.

32. The method of claim 31, further including the step of coupling at least one network device directly to the switching hub device, wherein each such network device may intercommunicate packets by means of the conventional network protocol during such second time intervals.

33. The method of claim 30, further including the step of configuring the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

34. The method of claim 30, further including the step of configuring the switching hub device during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

35. The method of claim 31, further including the step of configuring the switching hub device during each second time interval to directly couple each input port that is coupled to one of the at least one device adapter configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to one of the at least one device adapter similarly configured to intercommunicate packets by means of said conventional network protocol.

36. The method of claim 31, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

37. The method of claim 30, wherein the time schedule information is provided through a network link to each device adapter coupled to the switching hub device.

38. A method for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including the steps of:

providing a switching hub device having a plurality of input ports and a plurality of output ports, for transferring packets between selected input ports to selected output ports for transmission on a network;

providing at least one device adapter, each configured to be coupled to at least one network device and to one of said plurality of input ports and to one of said plurality output ports of the switching hub device through a network, for transmitting packets on the network between at least one of the coupled network devices and the switching hub device;

selectively synchronizing transferring of packets by the switching hub device and transmission of packets by each coupled device adapter;

periodically configuring the switching hub device to operate in (1) a first time interval wherein selected pairs of coupled device adapters can directly intercommunicate packets, and (2) a second time interval wherein device adapters may intercommunicate packets by means of a conventional network protocol.

39. The method of claim 38, further including the step of coupling at least one network device directly to the switching hub device, wherein each such network device may intercommunicate packets by means of said conventional network protocol during second time intervals.

40. The method of claim 38, further including the step of configuring the switching hub device to operate such that selected first time intervals are subdivided into at least two phases, wherein at least one coupled device adapter can directly intercommunicate packets with distinct other coupled device adapters during corresponding synchronized phases.

41. The method of claim 38, further including the step of configuring the switching hub device during each first time interval to directly couple selected ones of the input ports to corresponding selected ones of the output ports.

42. The method of claim 38, further including the step of configuring the switching hub device during each second time interval to directly couple each input port that is coupled to one of the at least one device adapter configured to intercommunicate packets by means of said conventional network protocol to each output port that is coupled to one of the at least one device adapter similarly configured to intercommunicate packets by means of said conventional network protocol.

43. The method of claim 38, wherein the conventional network protocol is a carrier sense multiple access with collision detect protocol.

44. The method of claim 38, wherein the step of synchronizing includes transmitting time schedule information through a network link to each device adapter coupled to the switching hub device.