Path diversity index for use in route selection

1. A method comprising:

receiving at a network device information on paths to a destination node;

determining a number of common nodes or links between at least two of said paths;

identifying a path length for each of said paths and comparing said path lengths to find a maximum path length;

dividing the number of common nodes or links by said maximum path length to calculate a path diversity index based on the number of common nodes or links; and

calculating said path diversity index for each combination of paths within a network and dividing a summation of said path diversity index for each combination of paths by a number of path combinations to calculate a network wide diversity index.

2. The method of claim 1 wherein calculating said path diversity index comprises determining the number of common nodes or links for each combination of said paths.

3. The method of claim 1 wherein said information identifies all nodes receiving a packet transmitted from a source node and destined for the destination node and an order the packet transversed all of said nodes.

4. The method of claim 1 wherein said path diversity index is calculated at a route control device in communication with a plurality of border routers located on an edge of a network in which the route control device is located, and said information is received from said plurality of border routers.

5. The method of claim 1 further comprising:

selecting a route to the destination node based on said path diversity index, wherein selecting a route comprises selecting a network.

6. The method of claim 1 wherein said path diversity index is equal to:

1−[(the number of common nodes or links)/(the maximum path length)].

7. An apparatus comprising:

a processor operable to receive information about paths between a source node and a destination node, determine a number of common nodes or links between a first path and each of a plurality of paths, calculate a relative path diversity index for each of said plurality of paths with respect to said first path, and select an alternate route for said first path based on said relative path diversity index; and

memory for storing said path information and said relative path diversity index;

wherein said relative path diversity index is calculated by dividing the number of common nodes or links between said first path and one of said plurality of paths by a maximum number of common nodes or links for all combinations of said first path and said plurality of paths.

8. The apparatus of claim 7 wherein said relative path diversity index is equal to:

1−[(the number of common nodes or links)/(a maximum of the number of common nodes or links for all combinations of said paths)].

9. The apparatus of claim 7 wherein the processor is configured for operation at a route control device in communication with a plurality of border routers located on an edge of a content provider network and operable to transmit said information.

10. The apparatus of claim 7 wherein said relative path diversity index is between zero and one.

11. The apparatus of claim 7 wherein the processor is configured for calculating a network wide diversity index.

12. An apparatus comprising:

means for receiving at a network device information on paths to a destination node;

means for determining a number of common nodes or links between at least two of said paths, identifying a path length for each of said paths, and comparing said path lengths to find a maximum path length;

means for calculating a path diversity index based on the number of common nodes or links, wherein means for calculating comprises means for dividing the number of common nodes or links by said maximum path length; and

means for calculating said path diversity index for each combination of paths within a network and dividing a summation of said path diversity index for each combination of paths by a number of path combinations to calculate a network wide diversity index.

13. The apparatus of claim 12 wherein said path diversity index is equal to:

1−[(the number of common nodes or links)/(the maximum path length)].

14. The apparatus of claim 12 wherein said path diversity index is equal to:

1−[(the number of common nodes or links)/(a maximum path length)].

15. The apparatus of claim 12 wherein the network device is a route control device for communication with a plurality of border routers located at an edge of a network.

16. The apparatus of claim 12 wherein said information identifies all nodes receiving a packet transmitted from a source node and destined for the destination node and an order the packet transversed all of said nodes.

17. The apparatus of claim 12 wherein means for calculating said path diversity index comprises means for determining the number of common nodes or links for each combination of said paths.