A bandwidth assignment polling algorithm to enhance the efficiency in QoS long‐reach EPONs

Abstract

A novel polling algorithm is proposed to provide subscriber differentiation at the upstream channel in long-reach EPONs. As operators and service providers prefer to operate at loads with no congestion and losses, the developed algorithm has been designed to improve the efficiency for those loads at which the network is likely to work. This new scheme permits to anticipate the transmission of some packets in order to take advantage of the wasted bandwidth between consecutive transmissions of ONUs. As a result, not only does this algorithm behave alike other polling algorithms for high loads, but it also improves the efficiency at low and medium loads, leading to a reduction in the mean packet delay. The new algorithm has been tested in different scenarios, motivated by the increasing interest in enlarging the long-reach EPON distances. Simulation results show that as the distance increases, the algorithm achieves a significant reduction of the mean packet delay for an extended range of loads.

Dynamic Bandwidth Allocation with Effective Utilization of Polling Interval over WDM/TDM PON

“…We suppose that wavelength l 1 is allocated to ONU 1 , ONU 2 , ONU 3 and wavelength l 2 is allocated to ONU 4 , ONU 5 , ONU 6 according to the GATE message of the previous cycle. Then in our scheme of DBA1, the request information of ONU 1 , ONU 2 , ONU 3 will be integrated and sent on the head of cycle on wavelength l 1 and the request information of ONU 4 , ONU 5 , ONU 6 will be integrated and sent on the head of cycle on wavelength l 2 .…”

“…So, how to fairly and effectively allocate the bandwidth resources in the network is of great importance and interest to WDM/ TDM PON. Dynamic bandwidth allocation (DBA) plays a crucial role in efficiently and fairly allocating the bandwidth among all users [6][7][8][9].…”

Offline and Online Multi-Thread Polling in Long-Reach PONs: A Critical Evaluation

“…For STP, excess bandwidth distribution has been intensely investigated within the offline scheduling framework, see e.g., [7], [8]. Excess bandwidth distribution for STP with the online scheduling framework has been examined in relatively few studies that either explored relatively complex excess management rules [38] or focused on distributing excess within the window of one preceding cycle [39] or detected gaps in the upstream transmission schedule [40]. A refined control-theory based adjustment of the prescribed limit according to service-level agreements is examined in [41].…”

“…We examine an elementary "bounded excess pool" approach for online excess bandwidth distribution in online MTP; adapting and examining other approaches, e.g., [38]- [40] is an interesting direction for future research. For the bounded excess pool approach, we let denote the excess bandwidth pool (in terms of upstream transmission window duration) available for the bandwidth allocation to the th ONU of thread in cycle .…”

Delay-Constrained Admission and Bandwidth Allocation for Long-Reach EPON

“…In [25], the authors propose a bandwidth allocation scheme for LR-EPON where at the beginning of each granting cycle, the OLT determines the idle upstream timeslots in the next cycle and credits one or both of the ONUs whose REPORT messages are causing the gap. In [26], an adaptive polling scheme is proposed for LR-EPON in order to differentiate various classes of service packets.…”