Praise for Fundamentals of WiMAX

10.3 Protocol Layering Across a WiMAX Network 34110.2.3 Reference PointsThe WiMAX NWG defines a reference point (RP) as a conceptual link that connects two groupsof functions that reside in different functional entities of the ASN, CSN, or MS. Referencepoints are not necessarily a physical interface, except when the functional entities on either sideof it are implemented on different physical devices. The WiMAX Forum will verify interoperabilityof all exposed RPs based only on specified normative protocols and procedures for a supportedcapability across an exposed RP.Figure 10.1 shows a number of reference points defined by the WiMAX NWG. These referencepoints are listed in Table 10.2.Release 1 will enforce interoperability across R1, R2, R3, R4, and R5 for all ASN implementationprofiles. Other reference points are optional and may not be specified and/or verifiedfor Release 1.10.3 Protocol Layering Across a WiMAX NetworkIt is instructive to view the end-to-end WiMAX architecture using the logical representationshown in Figure 10.2. The architecture is quite similar to most other wide area IP access networks,where a link-layer infrastructure is used for concentrating traffic of individual users, witha separate entity providing an IP address to the end-user device for access to IP-based applicationsand services. Here, ASN is the link-layer infrastructure providing link concentration, andCSN is the infrastructure providing IP address and access to IP applications. The concentratedlinks are forwarded from the ASN-GW to the CSN via a managed IP network.BSManagedIP NetworkASPMS/SSBSAccessNetworkASN-GWManagedIP NetworkCSNInternetBSApplicationApplicationIPIPLinkLink ConcentrationLink ForwardingFigure 10.2 Logical representation of the end-to-end WiMAX architecture