The $filter System Query Option is used to filter resource collections to return a subset of resources in a response. The subset includes only the resources that satisfy conditions specified in the query.
For example, to return only Production VAO sites, send the following request:
Please note that get a representation of a VAO site or failover plan with the specified ID, you must send the following request:
The $filter system query option supports a set of built-in filter operations and functions that can be used within these operations. For the full description of the syntax used for building requests, see the [OData-URL] syntax rule.