Versioning contains a list of version mappings and service root context. The format to use when returning JSON to describe the available versions. The type of JSON Formats supported by this filter. The supported values are COMPUTE and IDENTITY. COMPUTE: http://developer.openstack.org/api-ref-compute-v2.1.html IDENTITY: http://developer.openstack.org/api-ref-identity-v2.html Version mappings describe the versions available to the requester. The ID is responsible for two things. First, a service version's ID must uniquely identify the version mapping within the configuration: no two service versions may share the same ID. In addition, the ID must be the resource variant that follows the service root which identifies this version. For example, in "http://service.api.vendor.com/root/[v1.0/]path/to/resource", the version variant is within square brackets. The Repose destination ID is used to identify which destination in system model will answer to versioned requests that match this version mapping. A status describes the current operational state of the given service version. The status described here will be reflected in the service version list response. The VersionStatus type describes the list of valid version status. A MediaTypeList outlines a collection of valid media types supported by a given service version. A MediaType describes what content types the service version understands. The base of a given media type describes the simple MIME type that will be passed to the origin in the Accept header. The type attribute of a MediaType describes the MIME specific identifier for a media type of this specific version. This identifier can include a vendor namespace ( See RFC 2048) as well as a version suffix. When the filter receives this media type in accept header, it will send base media type to the origin service.