Proxy-controlled ATM subnetwork

• US 6,111,858 A
• Filed: 02/18/1997
• Issued: 08/29/2000
• Est. Priority Date: 02/18/1997
• Status: Expired due to Term

• Current Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Original Assignee: Virata (USA), Inc.
• Inventors: Greaves, David J., Bradbury, Richard J.
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): Qureshi, Afsar M.
• Application Number:
  US08/801,683
• Time in Patent Office: 1,288 Days
• Field of Search: 370/254, 370/255, 370/256, 370/257, 370/395, 370/396, 370/397, 370/400, 370/401, 370/402, 370/403, 370/404, 370/405, 370/406, 370/407, 370/408, 370/409, 370/465, 370/466 , 370/467, 370/398, 370/399
• US Class Current: 370/256
• CPC Class Codes: H04L 2012/5609 Topology
• CPC Class Codes: H04L 2012/5613 Bus (including DQDB)
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/76 Routing in software-defined topologies, e.g. routing between virtual machines
• CPC Class Codes: H04L 49/107 using shared medium
• CPC Class Codes: H04L 49/256 Routing or path finding in ATM switching fabrics
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

An ATM subnetwork, suitable for a low-cost home area network, comprises an interconnected mesh of simple ATM switches, end stations and multi-access buses implemented in fully-hardware configurations. Software for signalling and management functions does not reside in these devices, but rather is banished to computers outside the interconnected mesh. Specifically, an external controller acts a proxy for the simple ATM switches and performs all virtual channel connection set-up within the interconnected mesh. Additionally, proxy controllers manage each simple end station and proxy signalling agents permit standard ATM devices to be connected to the simple switches. These proxy processes communicate with the devices within the interconnected mesh via a control protocol of single cell messages delivered over dedicated permanent virtual circuits. The external controller performs a two-phase distributed topology determination algorithm to gain knowledge of the topology of the interconnected mesh sufficient to establish virtual channel connections.

Claims

1. A subnetwork using asynchronous transfer mode comprising:

at least one end station communicating with at least one switch, said at least one end station and said at least one switch forming an interconnected mesh;

a controller connected to said interconnected mesh;

at least one proxy executing on said controller; and

said proxy determining a virtual circuit in said interconnected mesh for routing data to and between said end stations.

2. The subnetwork of claim 1 wherein said at least one end station and said at least one switch are substantially dependent on said proxy and said at least one end station and said at least one switch cooperate with one another to receive commands from said proxy.

3. The subnetwork of claim 1 wherein said controller is external to said interconnected mesh and connected to said interconnected mesh at a single control point, said controller being further connected to an ATM network.

4. The subnetwork of claim 3 wherein data from said ATM network is presented to said interconnected mesh at said single control point.

5. The subnetwork of claim 1 wherein signalling and management functions of said switch are performed by said proxy.

6. The subnetwork of claim 5 further comprising a proxy controller acting as a proxy for said at least one end station, such that signalling and management functions of said end station are performed by said proxy controller.

7. The subnetwork of claim 5 further comprising a proxy signalling agent established on a demand basis for performing signalling function for said at least one switch, such that standard ATM devices may be connected without modification to said at least one switch.

8. The subnetwork of claim 5 further comprising a proxy signalling agent established on a demand basis for performing signalling function for said at least one switch, such that a standard ATM network may be connected without modification to said at least one switch.

9. The subnetwork of claim 5 wherein said controller communicates with said at least one switch via a control protocol.

10. The subnetwork of claim 1 further comprising dumb devices which cannot respond to a command protocol but which may be identified by said controller.

11. The subnetwork of claim 10 wherein the presence and nature of said dumb devices can be determined by the use of switch table entries.

12. The subnetwork of claim 10 wherein said dumb devices can be controlled by the use of switch table entries.

13. The subnetwork of claim 9 wherein said at least one switch comprises a virtual address space, said control protocol comprising single cell messages enabling said controller to read and write to locations within said virtual address space.

14. The subnetwork of claim 13 wherein said at least one switch has a unique address defined by the topology of the interconnection of said switch relative to said single control point.

15. The subnetwork of claim 14 wherein said address comprises the concatenated sequence of switch port numbers forming the route through said interconnected mesh from said single control point to said at least one switch, said route confined to a spanning tree superimposed on said interconnected mesh and rooted at said single control point.

16. The subnetwork of claim 1, where for each said at least one switch, one port is physically distinguished so that an installer of said switch will connect said distinguished port to another switch with the knowledge that communications to and from said controller will pass through said port, thereby denying access to masquerading controllers connected to or via other ports of said switch.

17. A subnetwork using asynchronous transfer mode comprising:

at least one end station communicating with at least one multi-access bus, said at least one end station and said at least one multi-access bus forming an interconnected mesh;

a controller connected to said interconnected mesh;

at least one proxy executing on said controller;

said proxy determining a virtual circuit in said interconnected mesh for routing data to and between said end stations; and

said at least one end station and said at least one multi-access bus cooperating with one another to receive commands from said proxy.

18. The subnetwork of claim 17 wherein said at least one multi-access bus may be a bidirectional or a unidirectional bus.

19. The subnetwork of claim 17 wherein said at least one multi-access bus comprises a ring, acting as a distributed switch.

20. The subnetwork of claim 17 wherein said at least one multi-access bus comprises a loop, acting as a distributed switch.

21. A method for managing communications in a subnetwork using asynchronous transfer mode comprising the steps of:

interconnecting at least one end station and at least one switch to form an interconnected mesh;

presenting data to said interconnected mesh at a point of entry to said interconnected mesh;

controlling said subnetwork by a proxy connected to said interconnected mesh; and

determining by said proxy a virtual circuit in said interconnected mesh for routing said data to and between said end stations.

22. The method according to claim 21 wherein said at least one end station and said at least one switch are substantially dependent on said proxy and cooperate with each other to receive commands from said proxy.

23. The method according to claim 21 wherein said proxy is external to said interconnected mesh and further connected to an ATM network, said presenting step presents data from said ATM network to said interconnected mesh.

24. The method according to claim 21 wherein said controlling step includes performing by said proxy signalling and management functions of said at least one switch.

25. The method according to claim 24 wherein said controlling step comprises the step of communicating by said proxy with said at least one switch via a control protocol.

26. The method according to claim 25 wherein said at least one switch comprises a virtual address space, said control protocol comprises single cell messages, and said communicating step comprises reading and writing by said proxy to locations within said virtual address space.

27. The method according to claim 26 wherein said communicating step further comprises addressing said at least one switch using a unique address defined by the topology of the interconnection of said switch relative to said point of entry.

28. The method according to claim 27 wherein said address comprises the concatenated sequence of switch port numbers forming the route through said interconnected mesh from said point of entry to said at least one switch, said route confined to a spanning tree superimposed on said interconnected mesh and rooted at said point of entry.

29. A method according to claim 24 wherein the controlling step further comprises the step of determining the topology of said interconnected mesh.

30. A method for managing communications in a subnetwork using asynchronous transfer mode comprising the steps of:

interconnecting at least one end station and at least one multi-access bus to form an interconnected mesh;

presenting data to said interconnected mesh at a point of entry to said interconnected mesh;

controlling said subnetwork by a proxy connected to said interconnected mesh; and

determining by said proxy a virtual circuit in said interconnected mesh for routing said data to and between said end stations.

31. The method according to claim 30 wherein said at least one multi-access bus may be a bidirectional or a unidirectional bus.

32. The method according to claim 30 wherein said at least one multi-access bus comprises a ring, acting as a distributed switch.

33. The method according to claim 30 wherein said at least one multi-access bus comprises a loop, acting as a distributed switch.

34. A method for determining a spanning tree of a network, said network having at least one switch, said switch having a plurality of ports, comprising the steps of:

sending by each switch a plurality of register commands, one register command being sent on each of said plurality of ports;

receiving said plurality of register commands by a controller;

selecting one of said received register commands;

acknowledging said switch identified by said selected register command comprising the step of;

sending a acknowledgment message to said switch;

including said identified switch in said spanning tree of a said network; and

propagating towards said controller by a previously acknowledged switch each register command received by said previously acknowledged switch.

35. The method according to claim 34 further comprising the step of discarding, by a non-acknowledged switch, each register command received by said non-acknowledged switch.

36. The method according to claim 34 wherein said sending step is periodically repeated by each non-acknowledged switch.

37. The method according to claim 34 wherein the propagating step transmits received register commands on the same port said previously-acknowledged switch received said acknowledgement message.

38. A method for determining the topology of a network, said network having at least one switch, at least one end station and at least one multi-access bus, comprising the steps of:

determining a spanning tree of said network; and

determining cross-links between said at least one switch, said at least one end station and said at least one multi-access bus within said network.

39. The method according to claim 38 wherein said step of determining the spanning tree further comprises comparing subsections of a prior configuration of said network with the present configuration of said network in order to retain knowledge of device identities in said network from said prior configuration.

40. The method according to claim 39 wherein said step of comparing subsections is undertaken to preserve logical addresses of devices in said network from said prior configuration of said network, even if physical addresses of said devices have changed within said network.

41. The method according to claim 38 wherein the location of devices without unique identifiers in said network are determined by having them communicate with said at least one end station.

42. The method according to claim 38 wherein the location of a first device in said network that only receives communication from said network can be determined by using a second device in said network.

43. The method according to claim 42 wherein either said first device or said second device or both are dumb devices.

44. A subnetwork using asynchronous transfer mode comprising:

at least one end station communicating with at least one switch, said at least one end station and said at least one switch forming an interconnected mesh, with data being presented to said interconnected mesh at a point of entry to said interconnected mesh;

a controller external to said subnetwork and connected to said interconnected mesh;

at least one proxy executing on said controller;

means for determining the topology of said interconnected mesh; and

said proxy determining a virtual circuit in said interconnected mesh for routing said data to and between said end stations by referencing said topology of said interconnected mesh.

45. A subnetwork using asynchronous transfer mode comprising:

at least one end station communicating with at least one switch, said at least one end station and said at least one switch forming an interconnected mesh, with input data being presented to said interconnected mesh at a point of entry to said interconnected mesh;

processor means external to said interconnected mesh and connected to said interconnected mesh;

means for determining topology of said interconnected mesh;

said processor means determining a virtual circuit in said interconnected mesh for routing said data to and between said end stations by referencing said topology of said interconnected mesh; and

said processor means appending virtual circuit information to said data prior to routing said data to said interconnected mesh.