Priority and policy based recovery in connection-oriented communication networks

• US 7,333,438 B1
• Filed: 06/21/2002
• Issued: 02/19/2008
• Est. Priority Date: 06/21/2002
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Shan, Tong, Rabie, Sameh A.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): NGUYEN, TOAN D
• Application Number:
  US10/176,060
• Time in Patent Office: 2,069 Days
• Field of Search: None
• US Class Current: 370/242
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 45/10 Routing in connection-oriented networks, e.g. X.25 or ATM
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS

Abstract

A recovery method for use in a connection-oriented network having nodes interconnected by links for establishing connections within the network, the method described enables the recovery of connections in the network in the event of a failure. The recovery method includes the following steps: (a) assigning connection re-routing priority to the connections in the network based on configured polices in response to the failure; and (b) creating release message bundles based on the assigned connection re-routing priority for use by the nodes in the network to recover connections. More specifically, a failure (e.g., link failure) could affect hundreds or thousands of connections passing through a node. To recover these connections, the node determines which connections should be recovered first and which connections can wait (or may never be recovered). The recovery method determines the priorities of re-routing connections after failure. After the re-routing priorities are determined for connections, the present invention provides mechanisms for bundling release messages and pacing the messages using hold-off timers to maximize the recovery of connections based on various network configurations and implementations.

Claims

1. A method for use in a connection-oriented network comprising a plurality of nodes interconnected by a plurality of links for establishing connections within the network, the method enabling the recovery of connections in the network in the event of a failure therein, the method comprising:

(a) assigning connection re-routing priority to the connections in the network based on configured polices in response to the failure;

(b) creating release message bundles based on the assigned connection re-routing priority for use by the nodes in the network to recover connections which includes;

(b1) creating a plurality of bundles of release messages of recovery requirements based on priority with reference to the re-routing in the network, the created bundles of release messages being in bundling order, the bundling ordered release messages being sent to nodes of the network; and

(c) if step (b1) is performed in a node which is neither a call originated nor a call destined node, sending a prescribed bundle of release messages to the plurality of nodes in the network which includes;

(c1) sending a first bundle of the bundling ordered release messages; and

in a case of another bundle being required to be sent, sending another bundle of the bundles of release messages after a predetermined hold-off timer value, wherein an initial value of the predetermined hold-off timer is determined from;

max{(t_prop,i)+(t_proc,i)+(t_rout,i) for all connections 1<

i<

N in a group, where (t_prop,i) represents propagation delay between a current node and a source node of a connection “

i”

, (t_proc,i) represents processing time of the release message at the source node of the connection “

i”

;

(t_rout,i) represents re-routing time at the source node of connection “

i”

; and

N is the number of connections, the current node being a node in the network detecting the failure and sending release messages to nodes of affected connections and the source node being an originating edge node of the connection.

2. The method of claim 1, wherein step (a) includes:

in a case of no connection re-routing priority being signaled by the network, assigning connection re-routing priority to the connections based on the configured policies, the assigned connection re-routing priority being used for creating the release message bundles.

3. The method of claim 2, wherein the assigned connection re-routing priority is based on at least one of service category, connection permanence, connection size and application type with reference to re-routing in the network.

4. The method of claim 2, wherein step (a) includes:

applying policy from a plurality of re-routing policies required for re-routing connections in the network, the applied policy being used for creating the release message bundles.

5. The method of claim 4, wherein the step of applying policy includes:

selecting a primary re-routing policy from the plurality of policies, wherein boundaries and ordering of the created release message bundles are not adjusted; and

selecting another re-routing policy from the plurality of polices, in a case of another re-routing policy being necessary, wherein bundle boundaries and ordering of the created release message bundles are adjusted.

6. The method of claim 2, further including:

in a case where the assigned connection re-routing priority is to be adjusted, adjusting the assigned connection re-routing priority based on a dynamic state of the network and adaptive policies, the adaptive policies comprising at least one of bandwidth pool occupancy, bandwidth pool usage, more active connections given priority, less active connections given priority and connection size with reference to the re-routing in the network; and

adjusting the created release message bundles.

7. The method of claim 6, wherein the step of adjusting the assigned connection re-routing priority includes:

applying policy from a plurality of re-routing policies required for re-routing connections in the network.

8. The method of claim 7, wherein the step of applying policy includes:

selecting a primary re-routing policy from the plurality of policies, wherein boundaries and ordering of the created release message bundles are not adjusted; and

selecting another re-routing policy from the plurality of polices, in a case of another re-routing policy being necessary, wherein bundle boundaries and ordering of the created release message bundles are adjusted.

9. The method of claim 6, wherein the step of adjusting the assigned connection re-routing priority includes:

determining whether the adaptive policies are used in deciding re-routing priority from a nodal configuration of the network.

10. The method of claim 6, further comprising:

after the step of creating release message bundles based on the assigned connection re-routing priority, storing the created release message bundles in a storage mechanism and wherein the step of adjusting the created release message bundles includes updating the created release message bundles stored in the storage mechanism.

11. The method of claim 6, wherein the step of creating release message bundles based on the assigned connection re-routing priority is performed, after the step of adjusting the assigned connection re-routing priority.

12. The method of claim 11, further comprising:

adjusting the created release message bundles; and

storing the adjusted release message bundles in a storage mechanism.

13. The method of claim 1, wherein the failure includes one or more of a link failure, a line card port failure within one of the plurality of nodes, a line card processor failure within one of the plurality of nodes, and a firmware failure within one of the plurality of nodes.

14. The method of claim 1, further comprising:

in a case of connection re-routing priority being signaled by the network, modifying the signaled connection re-routing priority based on the configured policies, wherein step (b) creates release message bundles based on the modified connection re-routing priority for provisioning to nodes in the network.

15. The method of claim 14, wherein the step of modifying the signaled connection re-routing priority based on the configured policies includes:

modifying the priority based on at least one of service category, connection permanence, connection size and application type with reference to re-routing in the network.

16. The method of claim 14, wherein the step of modifying the signaled connection re-routing priority based on the configured policies includes:

applying policy from a plurality of re-routing policies required for re-routing connections in the network, the applied policy being used for creating the release message bundles.

17. The method of claim 16, wherein the step of applying policy includes:

selecting a primary re-routing policy from the plurality of policies, wherein boundaries and ordering of the created release message bundles are not adjusted; and

selecting another re-routing policy from the plurality of polices, in a case of another re-routing policy being necessary, wherein bundle boundaries and ordering of the created release message bundles are adjusted.

18. The method of claim 7, further comprising:

in a case where the modified connection re-routing priority is required to be adjusted, adjusting the modified connection re-routing priority based on a dynamic state of the network and adaptive policies, the adaptive policies comprising at least one of bandwidth pool occupancy, bandwidth pool usage, more active connections given priority, less active connections given priority and connection size with reference to the re-routing in the network; and

adjusting the created release message bundles.

19. The method of claim 18, wherein the step of adjusting the modified connection re-routing priority includes:

determining whether the adaptive policies are used in deciding re-routing priority from a nodal configuration of the network.

20. The method of claim 18, further comprising:

after the step of creating release message bundles based on the modified connection re-routing priority, storing the created release message bundles in a storage mechanism and wherein the step of adjusting the created release message bundles includes updating the created release message bundles stored in the storage mechanism.

21. The method of claim 18, wherein the step of creating release message bundles based on the modified connection re-routing priority is performed, after the step of adjusting the modified connection re-routing priority.

22. The method of claim 21, further comprising:

adjusting the created release message bundles; and

storing the adjusted release message bundles in a storage mechanism.

23. The method of claim 1, further comprising the step of:

in a case of the step of creating a plurality of bundles of release messages being performed in a call originated node or a call destined node, sending the bundles of release messages to other nodes in the network.

24. The method of claim 23, wherein the step of sending the bundles of release messages includes:

sending release messages of further divided bundles, the further divided bundles being bundling ordered release messages of sub-divided bundles.

25. The method of claim 1, wherein the step of sending another bundle includes:

sending release messages of an individual one of the bundles upon expiration of time set for that individual bundle, after completion of sending release messages of a preceding one of the bundles, the time being set separately to the individual bundles.

26. The method of claim 1, wherein the step of sending the prescribed bundle of release messages includes:

sending release message of further divided bundles of the prescribed bundle, the further divided bundles being bundling ordered release messages of sub-divided bundles, each sub-divided bundle being sent with predetermined hold-off time required for that sub-divided bundle.

27. The method of claim 1, wherein the initial value of the predetermined hold-off timer is reduced by a first prescribed amount when backup connections exist between the first and second node of the network.

28. The method of claim 27, wherein the initial value of the predetermined hold-off timer is reduced by a second prescribed amount when pre-emption is permitted between the first and second node of the network.

29. The method of claim 28, wherein the first prescribed amount is larger than the second prescribed amount.

30. An apparatus for use in a connection-oriented network comprising a plurality of nodes interconnected by a plurality of links for establishing connections within the network, the method enabling recovery of connections in the network in the event of a failure therein, the apparatus comprising:

(a) a mechanism configured and adapted to assign connection re-routing priority to the connections in the network based on configured polices in response to the failure;

(b) a mechanism configured and adapted to create release message bundles based on the assigned connection re-routing priority for use by the nodes in the network for recovering connections which includes;

(b1) a mechanism configured and adapted to create a plurality of bundles of release messages of recovery requirements based on priority with reference to the re-routing in the network, the created bundles of release messages being in a bundling order, the bundling ordered release messages being sent to nodes of the network; and

(c) if the (b1) mechanism is situated in a node which is neither a call originated nor a call destined node, the apparatus comprises a further mechanism for sending a prescribed bundle of release messages to the plurality of nodes in the network, the further mechanism including;

(c1) a mechanism configured and adapted to send a first bundle of the bundling ordered release messages and, in a case of another bundle being required to be sent, sending another bundle of the bundles of release messages after a predetermined hold-off timer value, wherein an initial value of the predetermined hold-off timer is determined from;

max{(t_prop,i)+(t_proc,i)+(t_rout,i) for all connections 1<

i<

N in a group, where (t_prop,i) represents propagation delay between a current node and a source node of a connection “

i”

, (t_proc,i) represents processing time of the release message at the source node of the connection “

i”

;

(t_rout,i) represents re-routing time at the source node of connection “

i”

; and

N is the number of connections the current node being a node in the network detecting the failure and sending release messages to nodes of affected connections and the source node being an originating edge node of the connection.

31. The apparatus of claim 30, wherein the mechanism (a) includes:

(a1) a mechanism configured and adapted to apply policy from a plurality of re-routing policies required for re-routing connections in the network, the applied policy being used for creating the release message bundles.

32. The apparatus of claim 31, wherein the mechanism (a1) includes:

(a11) a mechanism configured and adapted to select a primary re-routing policy from the plurality of policies, wherein boundaries and ordering of the created release message bundles are not adjusted; and

(a12) a mechanism configured and adapted to select another re-routing policy from the plurality of polices, in a case of another re-routing policy being necessary, wherein bundle boundaries and ordering of the created release message bundles are adjusted.

33. The apparatus of claim 31, further including:

(d) a mechanism configured and adapted to adjust the assigned connection re-routing priority based on a dynamic state of the network and adaptive policies, the adaptive policies comprising at least one of bandwidth pool occupancy, bandwidth pool usage, more active connections given priority, less active connections given priority and connection size with reference to the re-routing in the network; and

to adjust the created release message bundles.

34. A computer program product for use in a connection-oriented network comprising a plurality of nodes interconnected by a plurality of links for establishing connections within the network to enable recovery of connections in the network in the event of a failure therein, the computer program product comprising computer readable medium encoded with computer program code for:

(a) assigning connection re-routing priority to the connections in the network based on configured polices in response to the failure;

(b) creating release message bundles based on the assigned connection re-routing priority for use by the nodes in the network to recover connections which includes;

(b1) creating a plurality of bundles of release messages of recovery requirements based on priority with reference to the re-routing in the network, the created bundles of release messages being in a bundling order, the bundling ordered release messages being sent to nodes of the network; and

(c) if step (b1) is performed in a node which is neither a call originated nor a call destined node, sending a prescribed bundle of release messages to the plurality of nodes in the network which includes;

(c1) sending a first bundle of the bundling ordered release messages; and

in a case of another bundle being required to be sent, sending another bundle of the bundles of release messages after a predetermined hold-off timer value, wherein an initial value of the predetermined hold-off timer is determined from;

max{(t_prop,i)+(t_proc,i)+(t_rout,i) for all connections 1<

i<

N in a group, where (t_prop,i) represents propagation delay between a current node and a source node of a connection “

i”

, (t_rout,i) represents processing time of the release message at the source node of the connection “

i”

;

(t_rout,i) represents re-routing time at the source node of connection “

i”

; and

N is the number of connections, the current node being a node in the network detecting the failure and sending release messages to nodes of affected connections and the source node being an originating edge node of the connection.

35. The computer program product of claim 34, wherein the computer readable program code devices for assigning connection re-routing priority includes:

applying policy from a plurality of re-routing policies required for re-routing connections in the network, the applied policy being used for creating the release message bundles.

36. The computer program product of claim 35, wherein the computer readable program code devices for applying policy includes:

selecting a primary re-routing policy from the plurality of policies, wherein boundaries and ordering of the created release message bundles are not adjusted; and

selecting another re-routing policy from the plurality of polices, in a case of another re-routing policy being necessary, wherein bundle boundaries and ordering of the created release message bundles are adjusted.

37. The computer program product of claim 35, further including:

adjusting the assigned connection re-routing priority based on a dynamic state of the network and adaptive policies, the adaptive policies comprising at least one of bandwidth pool occupancy, bandwidth pool usage, more active connections given priority, less active connections given priority and connection size with reference to the re-routing in the network; and

adjusting the created release message bundles.