Praise for Fundamentals of WiMAX

10.7 Quality-of-Service Architecture 351AuthenticationRelayKey ReceiverAuthenticationRelay ProtocolAK TransferProtocolAuthenticatorKeyDistributorAuthenticationRelayBase StationKey ReceiverAuthenticationRelay ProtocolAK TransferProtocolAuthenticatorSingleDeviceKeyDistributor(a)(b)Figure 10.8 ASN security architecture and deployment models: (a) integrated deployment modeland (b) stand-alone deployment modelFigure 10.9 shows the proposed QoS functional architecture as proposed by the WiMAXNWG. This architecture supports the dynamic creation, admission, activation, modification, anddeletion of service flows. The important functional entities in the architecture are as follows:Policy function. The policy function (PF) and a database reside in the home NSP. The PFcontains the general and application-dependent policy rules of the NSP. The PF database mayoptionally be provisioned by an AAA server with user-related QoS profiles and policies. The PFis responsible for evaluating a service request it receives against the provisioned. Servicerequests to the PF may come from the service flow authorization (SFA) function or from anapplication function (AF), depending on how the service flows are triggered.AAA server. The user QoS profiles and associated policy rules are stored in the AAAserver. User QoS information is downloaded to an SFA at network entry as part of the authenticationand authorization procedure. The SFA then evaluates incoming service requests againstthis downloaded user profile to determine handling. Alternatively, the AAA server can provisionthe PF with subscriber-related QoS information. In this case, the home PF determines howincoming service flows are handled.Service flow management. The service flow management (SFM) is a logical entity in theBS that is responsible for the creation, admission, activation, modification, and deletion of802.16e service flows. The SFM manages local resource information and performs the admissioncontrol (AC) function, which decides whether a new service flow can be admitted into thenetwork.Service flow authorization. The SFA is a logical entity in the ASN. A user QoS profile maybe downloaded into the SFA during network entry. If this happens, the SFA evaluates the incomingservice request against the user QoS profile and decides whether to allow the flow. If the userQoS profile is not with the SFA, it simply forwards the service flow request to the PF for decisionmaking. For each MS, one SFA is assigned as the anchor SFA for a given session and is responsiblefor communication with PF. Additional SFAs may exist in an NAP that relays QoS-relatedprimitives and applies QoS policy for that MS. The relay SFA that directly communicates with