**2.1.1 Implementation of BDAM**

The WiMAX Network Reference architecture is given in the fig. 3.

Fig. 3. WiMAX Network Reference Architecture.

Bandwidth allocation is done for all the service class for the three types of users as per fig. 2

Start

Allocate bandwidth to UGS service

Allocate bandwidth *to high-priority* service flows of this service

Allocate bandwidth to *regular* service flows of this service class

Allocate bandwidth to *low-priority* service flows of this service class

All service classes done

Stop

Yes

No

Move to the next service class (ertPS >> rtPS >> nrtPS >> BE)

From the algorithm in fig.2, we see that when the BS receives bandwidth requests for BE traffic from High-Prioirty, Regular and Low-Priority users, BS shall allocate bandwidth first to the high-priority user then the regular user and finally to the low-priority user

The WiMAX Network Reference architecture is given in the fig. 3.

Fig. 3. WiMAX Network Reference Architecture.

Fig. 2. DBAM Algorithm.

(Kumar et al. 2011a).

**2.1.1 Implementation of BDAM** 

Each network service provider (NSP) has a Authentication, Authorization and Accounting (AAA) server.. This server maintains the information about the users. The Access Service Network (ASN) interacts with the AAA server to obtain the information about the user.

The AAA server shall maintain a table of MAC address for the users and the priority value associated with the user. A sample state of the table could be as shown in Table-2


Table 2. Sample state table of priority values for users.

When the MS initiates the ranging process, it sends the Ranging Request (RNG-REQ). Upon receiving the ranging request, BS shall query the AAA server to obtain the priority value associated with the user. BS shall store the priority value for the user in its local cache.

Subsequently, when the MS makes bandwidth request for any of its service flows, BS shall check the priority of the MS. Based on the priority value, bandwidth shall be allotted to the service flow.
