Section: 14.7.3 Alternative Format of W-APN Operator Identifier
Content: For situations when the PDG serving the W-APN is located in such network that is not part of the GRX (i.e. the Interoperator IP backbone), the default Operator Identifier described in clause 14.7.2 is not available for use. This restriction originates from the ".3gppnetwork.org" domain, which is only available in GRX DNS for actual use. Thus an alternative format of W-APN Operator Identifier is required for this case. The Alternative W-APN Operator Identifiers shall be constructed as follows: "w-apn.<valid operator's REALM>" where: <valid operator's REALM> corresponds to REALM names owned by the operator hosting the PDG serving the desired W-APN. REALM names are required to be unique, and are piggybacked on the administration of the Public Internet DNS namespace. REALM names may also belong to the operator of the VPLMN. As an example, the W-APN OI for the Operator REALM "notareal.com" is coded in the Public Internet DNS as: "w-apn.notareal.com".