endments or revisions, as well as the use of appropriate IETF protocols and IEEE Ethernet standards. This framework permits decoupling of access network and corresponding entities from connectivity IP services, and allows network elements of the Connectivity Serving Network (CSN) to be agnostic of the IEEE 802.16 air interface. The architecture is based on functional decomposition principles (i.e., decomposition of features into functional entities across interopera- bility reference points without specific implementation assumptions, including the network entities and interfaces). Such a framework is modular and sufficiently flexible to accommodate a broad range of deployment options such as [5]: Scalable WiMAX networks (sparse to dense radio coverage and capacity); Diverse radio propagation environments (e.g., urban, suburban, or rural); Licensed and/or licensed-exempt spectrum; Hierarchical, non-hierarchical, or mesh topologies, and their variants; Coexistence of fixed, nomadic, portable, and mobile usage models; Interworking and integration with non-WiMAX core networks (e.g., 3GPP EPC) [7]. The architecture exploits the IEEE 802.16-2009 procedures and logical separation between such procedures and IP addressing, routing, and connectivity management procedures, and proto- cols to enable the use of the access architecture primitives in standalone and interworking deployment scenarios and it further supports sharing of Access Service Networks (ASN) by multiple Network Access Providers (NAP). The network design supports discovery and selection of accessible Network Service Providers (NSP) by an MS, and allows NAPs that employ one or more ASN topologies. Network Access Provider is a business entity that provides WiMAX radio access infrastructure to one or more WiMAX Network Service Providers. A NAP implements WiMAX network infrastructure using one or more ASNs. Network Service Provider is a business entity that provides IP connectivity and WiMAX services to WiMAX subscribers compliant with the service level agreem