Method and system for assessing network resource failures using passive shared risk resource groups

1. A method for assessing failures in network resources in a multilayered communication network, the method comprising:

in a processor, receiving indications of failures in one or more network resources from a plurality of network resources in a communication network comprising a plurality of network layers;

assessing the failures in the one or more failed network resources in each of progressively lower network layers from a highest network layer to a lowest network layer in said plurality of network layers, or in each of progressively higher network layers from the lowest network layer to the highest network layer in said plurality of network layers;

identifying a set of failed network resources from the one or more failed network resources in the progressively lower network layers causing failures in network layers above the progressively higher network layers, or from the one or more failed network resources in the progressively higher network layers causing failures in network layers below the progressively higher network layers;

determining that the set of failed network resources do not account for all failures in the one or more failed network resources;

identifying a group of network resources having a common risk attribute, wherein at least one failed network resource of the set of failed network resources has the common risk attribute; and

identifying, from the group of network resources, another failed network resource.

2. The method according to claim 1 , wherein identifying the set comprises identifying root causes of the failures in the communication network.

3. The method according to claim 1 , wherein receiving the indications of failures is performed at least partly in response to polling at least one of the plurality of network resources.

4. The method according to claim 1 , wherein identifying the set of failed network resources comprises identifying a minimal set of failed network resources causing all the failures in the communication network.

5. The method according to claim 1 , wherein the highest network layer and the lowest network layer comprise an internet protocol (IP) layer and a wavelength division multiplexing (WDM) layer respectively.

6. The method according to claim 1 , further comprising arranging the failures according to each network layer in said plurality of network layers.

7. The method according to claim 1 , wherein assessing the failures comprises

skipping network layers from which no failure indications are received.

8. The method according to claim 1 , further comprising if upon receiving no failure indications from said plurality of network layers in the communication network, deducing a suspected set of network resources from said plurality of network resources in said plurality of network layers that cause the failures in the communication network.

9. The method according to claim 8 , further comprising sending requests to the network resources in the suspected set to report their failure.

10. The method according to claim 9 , further comprising updating a database with the reported failures of the network resources in the suspected set.

11. The method according to claim 8 , further comprising automatically routing data traffic around the network resources in the suspected set.

12. The method according to claim 1 , wherein the group of network resources comprises a passive shared risk resource group (PSRG), further comprising:

assessing a likelihood of a PSRG failure for the PSRG.

13. The method according to claim 12 , further comprising outputting the set of failed network resources or the likelihood of the PSRG failure for the PSRG.

14. An apparatus for assessing failures in network resources in a multilayered communication network the apparatus comprising:

a memory; and

a processor configured to:

receive indications of failures in one or more network resources from a plurality of network resources in a communication network comprising a plurality of network layers;

assess the failures in the one or more failed network resources in each of progressively lower network layers from a highest network layer to a lowest network layer in said plurality of network layers, or in each of progressively higher network layers from the lowest network layer to the highest network layer in said plurality of network layers;

identify a set of failed network resources from the one or more failed network resources in the progressively lower network layers causing failures in network layers above the progressively higher network layers, or from the one or more failed network resources in the progressively higher network layers causing failures in network layers below the progressively higher network layers;

determine that the set of failed network resources do not account for all failures in the one or more failed network resources;

identify a group of network resources having a common risk attribute, wherein at least one failed network resource of the set of failed network resources has the common risk attribute; and

identify, from the group of network resources, another failed network resource.

15. The apparatus according to claim 14 , wherein the processor is configured to identify the set by identifying root causes of the failures in the communication network.

16. The apparatus according to claim 14 , wherein the processor is configured to receive the indications of failures by receiving the failure indications in response to polling at least one of said plurality of network resources.

17. The apparatus according to claim 14 , wherein the processor is configured to identify the set of failed network resources by identifying a minimal set of failed network resources causing all the failures in the communication network.

18. The apparatus according to claim 14 , wherein the highest network layer and the lowest network layer comprise an internet protocol (IP) layer and a wavelength division multiplexing (WDM) layer respectively.

19. The apparatus according to claim 14 , wherein the processor is configured to arrange the failures according to each network layer in said plurality of network layers.

20. The apparatus according to claim 14 , wherein the processor is configured to assess the failures by skipping network layers from which no failure indications are received.