Selective distribution messaging scheme for an optical network

• US 20040246914A1
• Filed: 06/03/2004
• Published: 12/09/2004
• Est. Priority Date: 06/06/2003
• Status: Active Grant

• Current Assignee: Dynamic Method Enterprises Limited
• Original Assignee: Dynamic Method Enterprises Limited
• Inventors: Hoang, Khoi Nhu, Sadananda, Santosh Kumar
• Granted Patent: US 7,848,651 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/62 Wavelength based optical switching H04Q11/0062
• CPC Class Codes: H04Q 2011/0086 Network resource allocation, dimensioning or optimisation
• CPC Class Codes: H04Q 2011/009 Topology aspects

Abstract

A selective distribution messaging scheme for an optical network. According to one embodiment of the invention, a wavelength division multiplexing optical network includes a number of nodes each having an optical cross connect and each having stored therein a database representing conversion free connectivity from that node to others of the nodes. In addition, each of the nodes employs a messaging scheme to propagate notification of changes in the optical network to others of the nodes to maintain their databases. The messaging scheme in each of the nodes transmits messages to only selected ones of the other nodes based at least in part on the conversion free connectivity to minimize the number of communications between nodes.

Claims

1. An apparatus comprising:

a wavelength division multiplexing optical network including a plurality of nodes each having an optical cross connect and each having stored therein a database representing conversion free connectivity from that node to others of the plurality of nodes, each of said nodes to employ a messaging scheme to propagate notification of changes in said optical network to others of said nodes to maintain said databases, said messaging scheme in each of said nodes transmitting messages to only selected ones of said plurality of nodes based at least in part on said conversion free connectivity to minimize the number of communications between nodes.

2. The apparatus of claim 1, wherein said changes including allocation and deallocation of paths and wavelengths thereon, addition and removal of wavelengths on links, addition and removal of links, and addition and removal of nodes.

3. The apparatus of claim 1, wherein for at least a given one of said nodes for at least one type of change, said selected ones of said plurality of nodes includes any nodes with which there is conversion free connectivity with said given node.

4. The apparatus of claim 1, wherein at least some of said messages have stored therein an indication of those of said nodes to which messages have already been sent for a given one of said changes, wherein those of said nodes receiving such messages only propagate such messages to any of said plurality of nodes with which there is conversion free connectivity and that are not identified by the received message.

5. The apparatus of claim 1, wherein the optical network is divided into a plurality of service levels, wherein different wavelengths on at least certain links of said optical network qualify for different ones of said plurality of service levels, and wherein each of said databases includes separate structures representing conversion free connectivity for each of said plurality of service levels.

6. The apparatus of claim 1, wherein the optical network employs a source based scheme for establishing communication paths according to said conversion free connectivity.

7. The apparatus of claim 6, wherein said communication paths include one or more of optical circuits, lightpaths, and end-to-end unidirectional paths.

8. The apparatus of claim 1, wherein at least some of said messages include a sent-to-set identifying other nodes to which notification of change has already been sent.

9. An apparatus comprising:

an access node, to be coupled in a wavelength division multiplexing optical network, including,

an optical cross connect,

a database to store a conversion free topology for said access node, and

a set of one or more modules to participate in a messaging scheme to propagate notification of changes in said optical network to other access nodes in the optical network to maintain the databases of said access nodes, said messaging scheme including transmitting messages to a set of said access nodes selected from only those of said access nodes of said optical network in said conversion free topology.

10. The apparatus of claim 9, wherein the access node also includes,

a link state database to store, for each link connected to said access node, a link state structure to store indicia of a port of the access node to which that link is connected and available wavelengths on that link, wherein a path is a series of two or more nodes connected by links on which a common set of one or more wavelengths is available for establishing one or more lightpaths, and wherein the access nodes in said conversion free topology are those access nodes in the optical network reachable using paths with the wavelengths in said link state database.

11. The apparatus of claim 9, wherein said changes including allocation and deallocation of paths and wavelengths thereon, addition and removal of wavelengths on links, addition and removal of links, and addition and removal of nodes.

12. The apparatus of claim 9, wherein said set of one or more modules to, responsive to detection of a change in the network, transmit a message to all of said access nodes in said conversion free topology.

13. The apparatus of claim 9, wherein said set of one or more modules to, responsive to a message from another of said nodes in the optical network indicating a change in the network, update said database as necessary, select as a new set any of said access nodes in said conversion free topology that are not identified in said message as already having been sent the message, update said message to also include said new set, and propagate said updated message to the access nodes in said new set.

14. The apparatus of claim 9, wherein the optical network is divided into a plurality of service levels, wherein different wavelengths on at least certain links of said optical network qualify for different ones of said plurality of service levels, wherein said database includes separate structures representing the conversion free topology for each of said plurality of service levels.

15. The apparatus of claim 9, wherein at least some of said messages include a sent-to-set identifying other nodes to which notification of change has already been sent.

16. The apparatus of claim 9, wherein said set of one or more modules, for at least certain types of said changes, determine whether any of the available paths in said conversion free topology include network resources affected and said selected set of said access nodes includes no nodes when none of the available paths in said conversion free topology include affected network resources.

17. The apparatus of claim 9, wherein said set of one or more modules, for at least certain types of said changes, transmit connectivity request messages and to which recipient access nodes transmits back connectivity response messages that are used to update said database.

18. A method comprising:

responsive to a change in a wavelength division multiplexing optical network including a plurality of access nodes, performing the following,

at least a first of said plurality of access nodes performing the following, transmitting a message regarding said change to only a selected set of said plurality of access nodes in said optical network based on a database representing conversion free connectivity from said first node to others of the plurality of access nodes, said message identifying the selected set of access nodes and said first access node; and

the access nodes in the selected set of access nodes, responsive to receiving said message, each performing the following, transmitting an updated version of the message to those of said plurality of access nodes with which there is conversion free connectivity and that are not already identified in the received message.

19. The method of claim 18, wherein said transmitting said message includes the following:

selecting as the selected set those of said plurality of access nodes with which there is conversion free connectivity.

20. The method of claim 18, wherein said transmitting said message includes the following:

selecting as the selected set those of said plurality of access nodes with which there is conversion free connectivity and that are not connected to the network resource that changed.

21. The method of claim 18, further comprising:

said first node updating said database.

22. The method of claim 18, further comprising:

said first node transmitting a connectivity request message to a set of one or more adjacent ones of said plurality of access nodes to discover changes to said conversion free connectivity;

those of said plurality of access nodes receiving a connectivity request message, performing the following,

transmitting back to the first access node a connectivity response message,

propagating said connectivity request message to any adjacent ones of said plurality of access nodes that may be able to determine additional conversion free connectivity having the first access node as the source node; and

said first access node updating said database responsive to receiving said connectivity response messages.

23. The method of claim 18, wherein:

at least a second of said plurality of access nodes, responsive to receiving the message or the updated version of said message, transmitting a connectivity request message to a set of one or more adjacent ones of said plurality of access nodes to discover changes to said second access node'"'"'s conversion free connectivity;

those of said plurality of access nodes receiving a connectivity request message, performing the following,

transmitting back to the second access node a connectivity response message, and

propagating said connectivity request message to any adjacent ones of said plurality of access nodes that may be able to determine additional conversion free connectivity having the second access node as the source node; and

said second access node updating a database responsive to receiving said connectivity request messages.

24. The apparatus of claim 18, wherein said change is one of allocation of a path and wavelength thereon, deallocation of a path and wavelength thereon, addition of a wavelength on a link, removal of a wavelength on a link, addition of a link, removal of a link, addition of a node, and removal of a node.

25. The apparatus of claim 18, wherein the optical network is divided into a plurality of service levels, wherein different wavelengths on at least certain links of said optical network qualify for different ones of said plurality of service levels, said database includes separate structures representing said conversion free connectivity for each of said plurality of service levels.

26. The apparatus of claim 18, wherein the optical network employs a source based scheme for establishing communication paths according to said conversion free connectivity.

27. The apparatus of claim 26, wherein said communication paths include one or more of optical circuits, lightpaths, and end-to-end unidirectional paths.

28. A method comprising:

a first access node of a plurality of access nodes in a wavelength division multiplexing optical network, responsive to receiving a message indicating a change in network resources and identifying others of said plurality of access nodes that have already received said message, performing the following,

updating a database that stores a conversion free topology for the first access node;

selecting as a set of access nodes any of the access nodes in said conversion free topology that are not identified by said message; and

transmitting an updated version of said message to said set of access nodes.

29. The method of claim 28, wherein said updating includes:

said first access node transmitting a connectivity request message to a set of one or more adjacent ones of said plurality of access nodes to discover any updates to said conversion free topology; and

said first access node receiving connectivity response messages.

30. The method of claim 29, wherein said updating includes:

instantiating a new conversion free connectivity database based on said connectivity responses.

31. The method of claim 28, wherein said change is one of allocation of a path and wavelength thereon, deallocation of a path and wavelength thereon, addition of a wavelength on a link, removal of a wavelength on a link, addition of a link, removal of a link, addition of a node, and removal of a node.

32. The method of claim 28, wherein the optical network is divided into a plurality of service levels, wherein different wavelengths on at least certain links of said optical network qualify for different ones of said plurality of service levels, said database includes separate structures representing the conversion free topology for each of said plurality of service levels.

33. The method of claim 28, wherein the optical network employs a source based scheme for establishing communication paths according to said conversion free connectivity.

34. The method of claim 33, wherein said communication paths include one or more of optical circuits, lightpaths, and end-to-end unidirectional paths.

35. A machine-readable medium that provides instructions that, if executed by a machine, will cause said machine to perform operations comprising:

a first access node of a plurality of access nodes in a wavelength division multiplexing optical network, responsive to receiving a message indicating a change in network resources and identifying others of said plurality of access nodes that have already received said message, performing the following,

updating a database that stores a conversion free topology for the first access node;

selecting as a set of access nodes any of the access nodes in said conversion free topology that are not identified by said message; and

transmitting an updated version of said message to said set of access nodes.

36. The machine-readable medium of claim 35, wherein said updating includes:

said first access node transmitting a connectivity request message to a set of one or more adjacent ones of said plurality of access nodes to discover any updates to said conversion free topology; and

said first access node receiving connectivity response messages.

37. The machine-readable medium of claim 36, wherein said updating includes:

instantiating a new conversion free connectivity database based on said connectivity responses.

38. The machine-readable medium of claim 35, wherein said change is one of allocation of a path and wavelength thereon, deallocation of a path and wavelength thereon, addition of a wavelength on a link, removal of a wavelength on a link, addition of a link, removal of a link, addition of a node, and removal of a node.

39. The machine-readable medium of claim 35, wherein the optical network is divided into a plurality of service levels, wherein different wavelengths on at least certain links of said optical network qualify for different ones of said plurality of service levels, said database includes separate structures representing the conversion free topology for each of said plurality of service levels.

40. The machine-readable medium of claim 35, wherein the optical network employs a source based scheme for establishing communication paths according to said conversion free connectivity.

41. The machine-readable medium of claim 40, wherein said communication paths include one or more of optical circuits, lightpaths, and end-to-end unidirectional paths.