1. A system comprising: a physical network database storing information about a plurality of resources in a network, wherein each of the plurality of resources is assigned in the physical network database to different resource tiers of one or more multi-tier resource groups based on a corresponding type of resource, the resource tiers including lower and higher tiers with respective lower and higher tier resources; and each lower tier resource at least partially relies on at least one of the higher tier resources; a policy database storing one or more policy-based shared risk rules defining diversity requirements for provisioning the plurality of resources in the network; and a network analysis device configured to: analyze a shared risk for each of said plurality of resources based on at least one of the policy-based shared risk rules stored in the policy database that defines a predetermined distance between and a predetermined length shared by at least two of said plurality of resources and a resource tier for at least a portion of said plurality of resources based on the information stored in the physical network database, determine whether the policy-based shared risk rule is violated based at least in part on at least two of said plurality of resources being physically and operationally diverse from one another while being within the predetermined distance of each other for the predetermined length and sharing the same resource tier based on the information stored in the physical network database, and assign a shared risk identifier to each of the at least two resources in the physical network database in response to the policy-based shared risk rule being violated.