Guaranteed Qos On Wimax Network Using Pbm

Guaranteed QoS on WiMAX network using PBM WiMAX (Worldwide Interoperability for Microwave Access) standard provides a business opportunity in delivering access for fixed and mobile broadband wireless services to residential and business subscribers. This standard is designed to handle different traffic types with different QoS mechanisms. The signaling and bandwidth allocation algorithms are highly dynamic with the ability to accommodate hundreds of connections. Emerging services such as Voice and Video services delivered over the WiMax network are highly sensitive to delay, jitter and bandwidth fluctuations and providing QoS guarantees are very critical. Deployment of different services, require a robust service provisioning architecture to manage them properly, and make them scaleable and extendable to new technologies. The following case study explains how the Policy based management can be deployed on a WiMAX network. WiMAX forum’s Network Working Group has developed a network reference model to serve as an architecture framework for WiMAX deployments. The overall network may be logically divided into three parts:  Connectivity Service Network (CSN), which provides IP connectivity and all the IP core network functions.  Access Service Network (ASN), containing gateways and base stations that form the radio access network.  Mobile Stations (MS) used by the end user to access the network In the WiAMX network architecture, multiple Access Service Networks (ASNs) are connected to Core Service Network (CSN). CSN contains policy server and AAA server to keep policy and subscriber databases. Each ASN has an ASN Gateway (ASN GW) which will be connected to one or more Base Stations (BSs). Each BS can communicate to multiple Subscriber Stations (SS) or Mobile Stations (MS) simultaneously. ASN GW will do the Admission Control and Service Flow Authorization (SFA) functions. Also it has policy enforcement function (PEF) to enforce the policy rules. BS does the Service Flow Management (SFM) to manage the packet flow. In the proposed architecture policy function is added in the BS to provision it through policy rules. SFA communicates with AAA server for authorization and to get the subscriber profile. Based on the profile, policy enforcement function (PEF) in ASN GW and BS will retrieve the appropriate policy rules and configure the parameters. If required, policy server (Policy Decision Points) can push the policy rules to PEFs to dynamically reconfigure the system parameters. In this approach, Policy Management Tool (PMT) is used to build the policy rules and SLAs. For different services (VOIP, IPTV, etc), the performance requirement are mapped on to QoS and traffic parameters. The SLAs shall be used in the AAA server for subscriber profile. During the admission request from a SS, admission control function of the ASN will get the subscriber profile with SLA. Admission control will pass the SLA to policy enforcement function (PEF) which in turn retrieves the details of the policies from the policy server (PDP). In this architecture, the same policies are sent to all the network elements in the end-to-end service flow path. The element specific parameter or command is translated at the element level (in PEP). Also, the policy can be defined to provision/configure the network elements without complexity. Since the COPS protocol works in client server model, the policies are pulled from policy server in the network elements when required and pushed to the network elements from policy server when there is change in the policy. The PEP will store the policy in the local database for the immediate processing. So more number of network elements can be managed in this architecture.