**3. User based packet classification algorithm**

We know that WiMAX supports 5 different types of service classes i.e. UGS, RTPS, eRTPS, nRTPS, BE. When a user generates data (ex: video packets) they are classified and placed into one of the 5 queues at SS (ex: Video packets are classified as RTPS packets and placed in the RTPS queue). As the user keeps generating data packets, these are classified and placed in one of the queues.

This method of classification is application specific. i.e. if the user keeps generating video packets they are always classified as RTPS packets and placed in RTPS queue and if the user generates web browsing/email packets they are generally classified as BE packets and places in BE queue. Packet classification is not user specific. i.e. there may be some users

allocating bandwidth to the different service flows. The steps for nDBAM algorithm as

**Step 1.** Users shall be allotted bandwidth as per one of the selected Seven methods of

BS keeps monitoring the network condition. BS could poll the SS to know their current queue length and the average queuing delays faced for each service flow. BS and SS can use the ranging mechanism to pass the information between them. **Step 2.** If the average queuing delay exceeds the QoS limits for the service class then the BS shall fallback from eDBAM to DBAM bandwidth allocation mechanism **Step 3.** BS checks with the SS if the average queuing delay has reduced. If yes then BS

sticks to DBAM. If the average queuing delay is still high them BS falls back to

**Step 4.** BS keeps monitoring the queuing delay. If the delay reduces and stays within

BS does ranging at periodically with the SS. Ranging process is generally done to adjust the power levels and the clock skews. During the ranging process, BS can also request for the current queue state for the different service flows. As a part of ranging response (RNG-RSP) The SS can send the queue state to BS. The information is generally sent as a TLV (Type-Length-Value) header. A new header will be required to send the queue state information.

**Type Length Value Scope** 

(ex: 105) 1 Average Queue delay for Service flow RNG-RSP

BS receives the RNG-RSP from all the SS for each of their service class. BS then checks if the queuing delay is within the QoS limits for the service class. If not then it means that the eDBAM algorithm is introducing delay for regular and low-priority users. So, BS shifts from

We know that WiMAX supports 5 different types of service classes i.e. UGS, RTPS, eRTPS, nRTPS, BE. When a user generates data (ex: video packets) they are classified and placed into one of the 5 queues at SS (ex: Video packets are classified as RTPS packets and placed in the RTPS queue). As the user keeps generating data packets, these are classified and placed

This method of classification is application specific. i.e. if the user keeps generating video packets they are always classified as RTPS packets and placed in RTPS queue and if the user generates web browsing/email packets they are generally classified as BE packets and places in BE queue. Packet classification is not user specific. i.e. there may be some users

First-come-first-serve (FCFS) method of bandwidth allocation.

acceptable limits then BS moves back to eDBAM algorithm

given below.

eDBAM.

**2.3.1 Implementation** 

Unused TLV type

eDBAM to DBAM.

in one of the queues.

Table 9 lists an example for the TLV.

Table 9. TLV header used to send Queue state.

**3. User based packet classification algorithm** 

who are ready to pay more if their browsing packets are treated as high priority packets i.e. the browsing packets generated by such users are treated as RTPS packets instead of BE packets and placed in RTPS queue.

There may be some users who may wish to pay less and still enjoy broadband facility. For such users we may want to downgrade even their high priority packets like RTPS packets and treat them as low priority BE packets. A third set of users may fall in-between the highpriority and low-priority users.

There shall be 8 different ways of classifying the packets as given in Table 10 (Lagare & Das 2009).


Table 10. Eight different ways of packet classification.
