Abstract
Ethernet passive optical network is a point-to-multipoint structure, and an effective media access protocol should be designed for collision avoidance and bandwidth allocation. Most previous researches have aimed to solve the problem using dynamic bandwidth allocation (DBA) algorithms with polling-based schemes. Unfortunately, idle channel time among the polling cycles cannot be overcome efficiently. In this paper, a dual-polling DBA (DP-DBA) algorithm which consists of an interpolling mechanism and an intrapolling mechanism is proposed. The interpolling mechanism helps eliminate the idle time problem while the intrapolling part aggregates the unused bandwidth of the light-loaded users and those due to nondefragmentation of the Ethernet frames of the general users. We also evaluate the performance of the DP-DBA algorithm by a comparison with the interleaved polling with adaptive cycle time (IPACT), the dynamic bandwidth allocation with a modified grant table generation algorithm (DBA2), the Double-Phase Polling (DPP), and the adaptive DBA algorithm with sorting report messages (Sort-DBA) schemes with simulation results. For greater realism with regard to general applications, we also simulate the asymmetric traffic loads at the optical network units (ONUs).The results show that DP-DBA outperforms the other DBA schemes under asymmetric load conditions.
Highlights
The number of subscribers served by FTTx equipment is strongly increasing [1]
We compare the performance of our proposed DP-dynamic bandwidth allocation (DBA) to five other well-known schemes, that is, interleaved polling with adaptive cycle time (IPACT) with fixed service (IPACT-fixed), IPACT with limited service (IPACTlimited), DBA2 with fair-excess (DBA2-FE), Double-Phase Polling (DPP), and Sort-DBA [11, 12, 16, 17]
For the IPACT-fixed, IPACT-limit, and DBA2-FE schemes, Bmin is calculated to be 15 Kbytes according to their definition
Summary
The number of subscribers served by FTTx equipment is strongly increasing [1]. The ongoing of market is prosperous in different regions of the world such as in Asia [2], the United States, and Latin America [3]. To deal with the idle time issue, they proposed an early allocation mechanism, called DBA2, which schedules lightly loaded ONUs without waiting till end of collection of all REPORT messages. It schedules heavily loaded ONUs only after the OLT receives all REPORT messages and performs computation for bandwidth allocation. In 2006, Zheng [15] proposed a bandwidth allocation method, which makes use of a tracker value to deal with the idle time problem under high traffic loads This algorithm improves the DBA2 idle time issue under heavy load conditions. This study is concluded with a few relevant remarks and addresses the direction of our future research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
