EPON 에서 QoS 보장을 위한 차등 대역폭 할당
Differentiated bandwidth allocation for QoS over EPON system
컴퓨터통신 EPON QoS 보장 대역폭 할당;
- 원문 URL
The subscriber access network is constrained by equipment and infrastructure not originally designed for high-bandwidth IP data. Whether riding on shorter copper drops or optical fiber, Ethernet is emerging as the future broadband protocol of choice, offering plug and play simplicity, IP efficiency, and low cost. Of particular interest is Ethernet PON, which combine low-cost point-to-multipoint optical infrastructure with low-cost high-bandwidth Ethernet. The future broadband access network is likely to be a combination of point-to-point and point-to-multipoint Ethernet, optimized for transporting IP data, as well as time critical voice and video. Ethernet-based passive optical network technology is being considered as a promising solution for next-generation broadband access network due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure. A major feature for this new architecture is the use of ashared transmission media between all users; hence, medium access control arbitration mechanisms are essential for the successful implementation of EPON: i.e., ensure a contention-free transmission and provide end users with an equal access to the shared media. In this thesis, we addressed the problem of dynamic bandwidth allocation in EPON. We augmented the dynamic bandwidth allocation to support QoS in a differentiated services framework. It was shown that the bandwidth allocation by credit-based priority scheduling, under our assumptions for traffic behavior, will result in an unexpected behavior for high priority class and we suggested the use of appropriate queue management with weighted priority scheduling to alleviate this problem. Our differentiated bandwidth guarantee allocation (DBGA) algorithm allocates effectively and fairly bandwidth among end users. Moreover, we showed that DBGA that perform the weighted bandwidth allocation for high priority packets result in better performance in terms of average and maximum packet delay, as well as network throughput compared with some other dynamic allocation algorithms. We proposed to use the multipoint control protocol defined within the IEEE 802.3ah Task Force to arbitrate the transmission of different users. We used simulation experiments to study the performance and validate the effectiveness of the proposed algorithm.