Online excess bandwidth distribution for Ethernet passive optical networks

Abstract

Excess bandwidth distribution techniques have recently been proposed to improve the dynamic bandwidth allocation in Ethernet passive optical networks (EPONs). We compare existing offline excess bandwidth distribution with conventional limited interleaved polling with adaptive cycle time (IPACT-limited) in terms of packet delay performance. We identify the factors that result in packet delay reduction with excess bandwidth distribution compared to IPACT-limited and discover that existing offline excess distribution mechanisms become unstable at moderate to high loads in long-range EPONs with large round-trip propagation delays. We propose a novel online excess bandwidth distribution (OEBD) mechanism to provide stable excess bandwidth distribution even at high loads in long-range EPONs. We demonstrate how OEBD can be tuned via parameters to provide grant sizing between limited and gated service.

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 .…”

Investigation of the DBA Algorithm Design Space for EPONs

“…As a result, the computation of is not possible, and therefore, excess bandwidth distribution cannot be supported when using an online scheduling framework unless an alternative method of accumulating excess bandwidth credits is devised. This possibility was investigated in [18], but the proposed method of accumulating excess bandwidth credits could lead to very large granting cycle lengths that will degrade performance.…”

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

“…This scheme is further improved to utilize the upstream gaps through inserted polling cycles [26]. In [27], a fair online distribution of the excessive bandwidth at each polling cycle is introduced in order to overcome the instability of the bandwidth distribution beyond certain critical loads. In [28], the authors have proposed a GATE-Driven bandwidth distribution scheme where the OLT uses the information collected from the REPORT messages and determines when to send the next GATE message.…”