Bonded deficit round robin scheduling for multi-channel networks
Computer Networks: The International Journal of Computer and Telecommunications Networking
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Fixed point-to-multipoint access networks connect the telecom provider via a shared coax and/or optical link with its subscribers. They rely on traffic scheduling algorithms to efficiently distribute the available bandwidth and to provide quality-of-service (QoS) guarantees. This dissertation is on the design and performance analysis of such algorithms. An Ethernet Passive Optical Network (EPON) is an access network technology offering high-speed access over optical fibre. The upstream scheduling algorithm is responsible for assigning the upstream channel bandwidth amongst the traffic of the different users and priorities. In this thesis several upstream scheduling algorithms, which use threshold reporting are proposed and studied. It is demonstrated that by using threshold reporting and appropriate scheduling, the available bandwidth can be fully utilized and low average delay and variation can be provided for high priority, time critical applications. The Hybrid Fibre Coax (HFC) networks are access technology which uses the legacy community antenna television cables and Data-over-Cable-Service-Interface-Specifications (DOCSIS) which standardize the MAC layer and QoS provisioning. The performance of the DOCSIS 2.0 protocol is studied by means of a novel simulator that models in detail the physical medium dependent the MAC layers. In subscriber access networks, typically high-speed network routers are responsible for the downstream scheduling. The thesis considers packet scheduling algorithms for high-speed networks and proposes a novel algorithm—called Last Backlogged First Served-Deficit Round Robin (LBFS-DRR). It has constant time complexity and bounded fairness and latency, which is proved analytically. The latency bound and the fairness of the Surplus Round Robin are also derived. Channel bonding or the bonding of several channels together to create a larger bandwidth pipe, is defined in DOCSIS 3.0 for HFC access networks. Two algorithms for downstream scheduling for channel bonded networks which use different queuing mechanisms are proposed. The dependence of the latency of the bonded scheduler from the one of the scheduler for a single channel is derived analytically. One of the algorithms—the Bonded Deficit Round Robin—is proven to have bounded latency. The two algorithms are further compared via simulations and the design trade-offs are identified.