Architectures for communication networks

• US 6,741,572 B1
• Filed: 12/03/1999
• Issued: 05/25/2004
• Est. Priority Date: 09/27/1999
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Hobbs, Christopher W. L., Graves, Alan F.
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Wilson, Robert W.
• Application Number:
  US09/453,282
• Time in Patent Office: 1,635 Days
• Field of Search: 370/400, 370/401, 370/254, 370/255, 370/357, 370/389, 370/229, 370/235, 359/119, 713/201, 714/9, 709/238, 709/241
• US Class Current: 370/254
• CPC Class Codes: H04L 41/082 the condition being updates or upgrades of network functionality
• CPC Class Codes: H04L 41/0856 by backing up or archiving configuration information
• CPC Class Codes: H04L 41/0869 Validating the configuration within one network element

Abstract

In a communications network comprising a plurality of interconnected nodes, each node comprises at least one network device requiring allocated transmission channels, a switch connected to the network device for configuring transmission channels connected to other nodes, and a configuration controller connected to the network device and to the switch for controlling configuration of the transmission channels. The configuration controller receives signals from the network device indicative of traffic load on the network device, processes the received signals to determine that reconfiguration of the transmission channels is favoured and determines a favoured reconfiguration of the transmission channels. The configuration controller also communicates with configuration controllers at other nodes to determine paths between nodes for reconfiguration of the transmission channels, and communicates with the switch, configuration controllers at other nodes and the network device to implement reconfiguration of the transmission channels. The network devices may be routers, data switches, servers or combinations thereof.

Claims

1. A communications network, comprising a plurality of interconnected nodes, each of the plurality of said nodes comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller being operable;

to receive from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

to process the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

to communicate with configuration controllers at other nodes to determine a paths between nodes for implementation of the favoured modified allocation of the transmission channels; and

to communicate with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

2. A network as defined in claim 1, wherein the ABUD at a particular node is selected from a group consisting of routers, data switches, servers.

3. A network as defined in claim 1, wherein the configuration controller at a particular node is operable:

to receive signals comprising traffic data from the ABUD; and

to process the received traffic data to determine that allocation of a transmission channel to a particular route is favoured.

4. A network as defined in claim 1, wherein the configuration controller at a particular node is operable:

to receive signals comprising transmission channel allocation request messages from the ABUD; and

to process the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.

5. A network as defined in claim 3 or claim 4, wherein the configuration controller at the particular node is operable to determine a possible path for the transmission channel to be allocated.

6. A network as defined in claim 4, wherein:

the configuration controller at the particular node comprises a storage device for storing a map of network connectivity; and

the configuration controller at the particular node is operable to consult the map of network connectivity to determine the possible path for the transmission channel to be allocated.

7. A network as defined in claim 5, wherein the configuration controller at the particular node is operable:

to send transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

to receive reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible path, to communicate with the switch, configuration controllers at other nodes and the ABUD to implement allocation of the transmission channel to the particular route.

8. A network as defined in claim 4, wherein the configuration controller at the particular node is operable:

to send transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

to receive reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to a reply message indicating that the transmission channel can be allocated at an adjacent node on the possible path, to communicate with the switch, the configuration controller at the adjacent node and the ABUD to implement allocation of the transmission channel to the particular route between the particular node and the adjacent node.

9. A network as defined in claim 1, wherein a configuration controller at a particular node is operable to communicate with configuration controllers at other nodes according to a connection-oriented protocol:

to temporarily reserve available transmission channels on a span-by-span basis until transmission channels are reserved for an entire end-to-end path; and

to book for use the temporarily reserved transmission channels upon confirmation that available transmission channels are reserved for the entire end-to-end path.

10. A network as defined in claim 1, wherein said buffer statistics comprise data selected from the group consisting of buffer fill levels, buffer rates of fill and numbers of buffer overflows.

11. A network node for a communications network, comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller being operable;

to receive from the ABUD butter statistics characterizing the fill of buffers connected to output ports of the ABUD;

to process the received buffer statistics to determine that a modified allocation of the transmission channels Is favoured and to determine a favoured modified allocation of the transmission channels;

to communicate with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured modified allocation of the transmission channels; and

to communicate with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

12. A network node as defined in claim 11, wherein the ABUD is selected from a group consisting of routers, data switches and servers.

13. A network node as defined in claim 11, wherein the configuration controller is operable:

to receive signals comprising traffic data from the ABUD; and

to process the received traffic data to determine that allocation of a transmission channel to a particular route is favoured.

14. A network node as defined in claim 11, wherein the configuration controller is operable:

to receive signals comprising transmission channel allocation request messages from the ABUD; and

to process the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.

15. A network node as defined in claim 13 or claim 14, wherein the configuration controller is operable to determine a possible path for the transmission channel to be allocated.

16. A network node as defined in claim 15, wherein:

the configuration controller comprises a storage device for storing a map of network connectivity; and

the configuration controller is operable to consult the map of network connectivity to determine the possible path for the transmission channel to be allocated.

17. A network node as defined in claim 15, wherein the configuration controller is operable:

to send transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

to receive reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible path, to communicate with the switch, configuration controllers at other nodes and the ABUD to implement allocation of the transmission channel to the particular route.

18. A network node as defined in claim 14, wherein the configuration controller is operable:

to send transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

to receive reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes, and

in response to a reply message indicating that the transmission channel can be allocated at an adjacent node on the possible path, to communicate with the switch, the configuration controller at the adjacent node and the ABUD to implement allocation of the transmission channel to the particular route between the particular node and the adjacent node.

19. A network node as defined in claim 11, wherein the configuration controller is operable to communicate with configuration controllers at other nodes according to a connection-oriented protocol:

to temporarily reserve available transmission channels on a span-by-span basis until transmission channels are reserved for an entire end-to-end path; and

to book for use the temporarily reserved transmission channels upon confirmation that available transmission channels are reserved for the entire end-to-end path.

20. A network node as defined in claim 11, wherein said buffer statistics comprise data selected from the group consisting of buffer fill levels, buffer rates of till and numbers of buffer overflows.

21. A network node as defined in claim 11, wherein the configuration controller is operable:

to identify a network path to which a port having unfavourable buffer statistics belongs;

to assess buffer fill statistics for other ports in the identified network path; and

to determine a favoured reconfiguration of the transmission channels based on the buffer fill statistics for multiple ports in the identified network path.

22. A communications network, comprising a plurality of interconnected nodes, each of the plurality of said nodes comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller comprising a storage device for storing policy rules; and

being operable;

to download policy rules from a central management system;

to receive from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

to apply the policy rules in processing the received buffer statistics to determine that allocation of a transmission channel to a particular route is favoured;

to communicate with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured allocation of the transmission channel to a particular route; and

to communicate with the switch configuration controllers at other nodes and the ABUD to implement the favoured allocation of the transmission channel.

23. A network node for a communications network comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller comprising a storage device for storing policy rules and

being operable;

to download policy rules from a central management system;

to receive from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

to apply the policy rules in processing the received buffer statistics to determine that allocation of a transmission channel to a particular route is favoured;

to communicate with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured allocation of the transmission channel to a particular route; and

to communicate with the switch, configuration controllers at other nodes and the ABUD to implement the favoured allocation of the transmission channel.

24. A configuration controller, communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the configuration controller comprising:

at least one processor; and

at least one storage device connected to the at least one processor, the storage device storing instructions for execution by the processor and storing policy rules, the instructions comprising instructions for;

downloading policy rules from a central management system;

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

applying the policy rules in processing the received buffer statistics to determine that allocation of a transmission channel to a particular route is favoured;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured allocation of a transmission channel; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured allocation of the transmission channel.

25. A configuration controller for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the configuration controller comprising:

at least one processor; and

at least one storage device connected to the at least one processor, the storage device storing instructions for execution by the processor, the instructions comprising instructions for;

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

processing the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to a determined oath.

26. A configuration controller as defined in claim 25, wherein the instructions comprise:

instructions for determining that a transmission channel is underutilized; and

instructions for communicating with the switch, configuration controllers at other nodes and the ABUD to reallocate the underutilized transmission channel to a pool of spare transmission channels.

27. A configuration controller as defined in claim 25, wherein the instructions comprise instructions for:

receiving signals comprising traffic data from the ABUD; and

processing the received traffic data to determine that allocation of a transmission channel to a particular route is favoured.

28. A configuration controller as defined in claim 25, wherein the instructions comprise instructions for:

receiving signals comprising transmission channel allocation request messages from the ABUD; and

processing the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.

29. A configuration controller as defined in claim 27, or claim 28, wherein the instructions comprise instructions for determining a possible path for the transmission channel to be allocated.

30. A configuration controller as defined in claim 29, comprising a storage device for storing a map of network connectivity, wherein the instructions comprise instructions for consulting the map of network connectivity to determine the possible path for the transmission channel to be allocated.

31. A configuration controller as defined in claim 29, wherein the instructions comprise instructions for:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible path, communicating with the switch, configuration controllers at other nodes and the ABUD to implement allocation of the transmission channel to the particular route.

32. A configuration controller as defined in claim 28, wherein the instructions comprise instructions for:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to a reply message indicating that the transmission channel can be allocated at an adjacent node on the possible path, communicating with the switch, the configuration controller at the adjacent node and the ABUD to implement allocation of the transmission channel to the particular route between the particular node and the adjacent node.

33. A configuration controller as defined in claim 25, wherein the instructions comprise instructions for communicating with configuration controllers at other nodes according to a connection-oriented protocol:

to temporarily reserve available transmission channels on a span-by-span basis until transmission channels are reserved for an entire end-to-end path; and

to book for use the temporarily reserved transmission channels upon confirmation that available transmission channels are reserved for the entire end-to-end path.

34. A configuration controller as defined in claim 25, wherein said buffer statistics comprise data selected from the group consisting of buffer fill levels, buffer rates of fill and numbers of buffer overflows.

35. A configuration controller as defined in claim 25, wherein the instructions comprise instructions for:

identifying a network path to which a port having unfavourable buffer statistics belongs;

assessing buffer fill statistics for other ports in the identified network path; and

determining a favoured reconfiguration of the transmission channels based on the buffer fill statistics for multiple ports in the identified network path.

40. A medium as defined in claim 31, wherein the instructions comprise instructions for:

receiving signals comprising transmission channel allocation messages from the ABUD; and

processing the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.

44. A medium as defined in claim 40, wherein the instructions comprise instructions for:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to a reply message indicating that the transmission channel can be allocated at an adjacent node on the possible path, communicating with the switch, the configuration controller at the adjacent node and the ABUD to implement allocation of the transmission channel to the particular route between the particular node and the adjacent node.

36. A processor readable medium storing instructions for execution by a configuration controller for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the instructions comprising instructions for:

downloading policy rules from a central management system;

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

applying the policy rules in processing the received buffer statistics to determine that allocation of a transmission channel to a particular route is favoured;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured allocation of a transmission channel; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured allocation of the transmission channel.

37. A processor readable medium storing instructions for execution by a configuration controller for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the instructions comprising instructions for:

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

processing the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to a determined path.

38. A medium as defined in claim 37, wherein the instructions comprise:

instructions for determining that a transmission channel is underutilized; and

instructions for communicating with the switch, configuration controllers at other nodes and the ABUD to reallocate the underutilized transmission channel to a pool of spare transmission channels.

39. A medium as defined in claim 37, wherein the instructions comprise instructions for:

receiving signals comprising traffic data from the ABUD; and

processing the received traffic data to determine that allocation of a transmission channel to a particular route is favoured.

41. A medium as defined in claim 39, or claim 40, wherein the instructions comprise instructions for determining a possible path for the transmission channel to be allocated.

42. A medium as defined in claim 41, wherein the instructions comprise instructions for consulting a map of network connectivity to determine the possible path for the transmission channel to be allocated.

43. A medium as defined in claim 41, wherein the instructions comprise instructions for:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible path, communicating with the switch, configuration controllers at other nodes and the ABUD to implement allocation of the transmission channel to the particular route.

45. A medium as defined in claim 37, wherein the instructions comprise instructions for communicating with configuration controllers at other nodes according to a connection-oriented protocol:

to temporarily reserve available transmission channels on a span-by span basis until transmission channels are reserved for an entire end-to-end path; and

to book for use the temporarily reserved transmission channels upon confirmation that available transmission channels are reserved for the entire end-to-end path.

46. A medium as defined in claim 37, wherein said buffer statistics comprise data selected from the group consisting of buffer fill levels, buffer rates of fill and numbers of buffer overflows.

47. A medium as defined in claim 37, wherein the instructions comprise instructions for:

identifying a network path to which a port having unfavourable buffer statistics belongs;

assessing buffer fill statistics for other ports in the identified network path; and

determining a favoured reconfiguration of the transmission channels based on the buffer fill statistics for multiple ports in the identified network path.

48. A method for operating a configuration controller at a node in a communications network for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the method comprising:

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

processing the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a paths between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

49. A method as defined in claim 48, comprising:

determining that a transmission channel is underutilized; and

communicating with the switch, configuration controllers at other nodes and the ABUD to reallocate the underutilized transmission channel to a pool of spare transmission channels.

50. A method as defined in claim 48, comprising:

receiving signals comprising traffic data from the ABUD; and

processing the received traffic data to determine that allocation of a transmission channel to a particular route is favoured.

51. A method as defined in claim 48, comprising:

receiving signals comprising transmission channel allocation request messages from the ABUD; and

processing the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.

52. A method as defined in claim 50 or claim 51, comprising determining a possible path for the transmission channel to be allocated.

53. A method as defined in claim 52, comprising consulting a map of network connectivity to determine the possible path for the transmission channel to be allocated.

54. A method as defined in claim 52, comprising:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible path, communicating with the switch, configuration controllers at other nodes and the ABUD to implement allocation of the transmission channel to the particular route.

55. A method as defined in claim 51, comprising:

sending transmission channel allocation request messages to configuration controllers at other nodes on the possible path;

receiving reply messages from the configuration controllers at other nodes on the possible path, the reply messages indicating whether the transmission channel can be allocated at the other nodes; and

in response to a reply message indicating that the transmission channel can be allocated at an adjacent node on the possible path, communicating with the switch, the configuration controller at the adjacent node and the ABUD to implement allocation of the transmission channel to the particular route between the particular node and the adjacent node.

56. A method as defined in claim 48, comprising communicating with configuration controllers at other nodes according to a connection-oriented protocol:

to temporarily reserve available transmission channels on a span-by-span basis until transmission channels are reserved for an entire end-to-end path; and

to book for use the temporarily reserved transmission channels upon confirmation that available transmission channels are reserved for the entire end-to-end path.

57. A method as defined in claim 48, wherein said buffer statistics comprise data selected from the group consisting of buffer fill levels, buffer rates of fill and numbers of buffer overflows.

58. A method for operating a configuration controller at a node in a communications network for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the method comprising:

downloading policy rules from a central management system;

end

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

applying the policy rules in processing the received buffer statistics to determine that allocation of a transmission channel to a particular route is favoured;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured allocation of a transmission channel; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured allocation of the transmission channel.

59. A communications network, comprising a plurality of interconnected nodes, each of the plurality of said nodes comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller being operable;

to receive from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

to apply network traffic policy rules to the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

to communicate with configuration controllers at other nodes to determine a path between nodes for Implementation of the favoured modified allocation of the transmission channels; and

to communicate with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

60. A network as defined in claim 59, wherein the configuration controller is operable:

to identify a network path to which a port having unfavourable buffer statistics belongs;

to assess buffer fill statistics for other ports in the identified network path; and

to determine a favoured reconfiguration of the transmission channels based on the buffer fill statistics for multiple ports in the identified network path.

61. A network node for a communications network, comprising:

at least one Agile Bandwidth Usage Device (ABUD);

a switch connected to the ABUD for configuring transmission channels connected to other nodes; and

a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels, the configuration controller being operable;

to receive from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

to apply network traffic policy rules to the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

to communicate with configuration controllers at other nodes to determine a oaths between nodes for implementation of the favoured modified allocation of the transmission channels; and

to communicate with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

62. A configuration controller for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the configuration controller comprising:

at least one processor; and

at least one storage device connected to the at least one processor, the storage device storing instructions for execution by the processor, the instructions comprising instructions for;

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

applying network traffic policy rules to the received buffer statistics to determine that a modified allocation of the transmission channels is favoured

and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a oath between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

63. A processor readable medium storing instructions for execution by a configuration controller for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the instructions comprising instructions for:

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of he ABUD;

applying network traffic policy rules to the received buffer statistics to determine that a modified allocation of the transmission channels is favoured and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a path between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch,configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

64. A method for operating a configuration controller at a node in a communications network for communicating with an Agile Bandwidth Usage Device (ABUD) requiring allocated transmission channels and a switch connected to the ABUD at a network node to configure transmission channels connected to other nodes of the network, the method comprising:

receiving from the ABUD buffer statistics characterizing the fill of buffers connected to output ports of the ABUD;

applying network traffic policy rules to the received buffer statistics to determine that a modified allocation of the transmission channels is favoured favoured and to determine a favoured modified allocation of the transmission channels;

communicating with configuration controllers at other nodes to determine a oath between nodes for implementation of the favoured modified allocation of the transmission channels; and

communicating with the switch, configuration controllers at other nodes and the ABUD to implement the favoured modified allocation of the transmission channels according to the determined path.

65. A method as defined in claim 64, wherein further comprising:

identifying a network path to which a port having unfavourable buffer statistics belongs;

assessing buffer fill statistics for other ports in the identified network path; and

determining a favoured reconfiguration of the transmission channels based on the buffer fill statistics for multiple ports in the identified network path.