Open Access in EPON using Dual SLAs
Published in part in OFC 2005 and ICC 2005, and submitted for publication in IEEE Journal of Selected Areas in Communications
Abstract:
The Ethernet Passive Optical Network (EPON) is an attractive solution for high bandwidth access networks. In the context of a broadband access network, the term open access implies the ability of multiple service providers to share the deployed access network infrastructure to make services available to the end users. Multiple services may thereby be delivered over a shared access channel. Open access requires fairness in terms of throughput, delay, jitter, and other network parameters in the access channel among the sharing entities, namely service providers and end users. Since the traffic in an access network is very bursty, an access network may be frequently subjected to very high loads for brief durations of time. Meeting the above fairness requirements under such conditions is very challenging.
In this study, we first motivate the problem of meeting fairness requirements simultaneously to both service providers and users, which are located at opposite ends of an access channel. We then investigate the importance of two different sets of Service Level Agreements (SLAs), which we call Dual SLAs. After formulating a mathematical model, we propose an efficient scheduling algorithm to meet Dual SLAs which is based on the well-known concept of max-min fairness.
We then demonstrate the effectiveness of our proposed algorithm through simulations using a discrete-event-simulator-based EPON set-up, which compares the fairness of the Dual-SLA scheduling algorithm with that of other traditional fair queuing algorithms such as Deficit Round Robin (DRR).
Fair Queuing using Service Envelopes (FQSE) in EPON
Published in part in OFC 2004 and IEEE Journal of Selected Areas in Communications, October 2004
Abstract:
We propose and investigate the characteristics of a fair queueing with service envelopes (FQSE) algorithm—a hierarchical fair-share scheduling algorithm for access networks based on a remote scheduling system such as Ethernet passive optical networks (EPON) or cable TV network. FQSE is designed to overcome the limiting factors of a typical remote scheduling system such as large control-plane delay, limited control-plane bandwidth, and significant queue switch-over overhead. The algorithm is based on a concept of service envelope—a function representing the fair allocation of resources based on a global network condition called satisfiability parameter (SP). We define properties of cousin-fairness and sibling-fairness and show the FQSE to be cousin-fair. FQSE is unique in that it is the only hierarchical algorithm that is simultaneously cousin-fair. Furthermore, we show the necessary techniques to adapt FQSE to variable-sized packet-based networks. We analyze FQSE performance in EPON serving 1024 independent queues and demonstrate FQSE's ability to provide guaranteed bandwidth to each queue and to share the excess bandwidth fairly.
WDM-PON Architectures
Published in part in Journal of Optical Networking, November 2005 and as part of a book chapter
Abstract:
The passive optical network (PON) is an optical fiber based network architecture, which can provide much higher bandwidth in the access network compared to traditional copper-based networks. Incorporating wavelength-division multiplexing (WDM) in a PON allows one to support much higher bandwidth compared to the standard PON, which operates in the “single-wavelength mode” where one wavelength is used for upstream transmission and a separate one is used for downstream transmission. We present a comprehensive review of various aspects of WDM-PONs proposed in the literature. This includes enabling device technologies for WDM-PONs and network architectures, as well as the corresponding protocols and services that may be deployed on a WDM-PON. The WDM-PON will become a revolutionary and scalable broadband access technology that will provide high bandwidth to end users.
Routing and Scheduling on Lambda-Grids
Published in part in ICC 2004 and PFLDNet 2005
Abstract:
In many application domains, there exists a need to aggregate information from information repositories distributed around the world. In an effort to better link these resources in a unified manner, middleware researchers put forth the notion of a grid. With this context, we consider the problem of aggregating files from distributed databases to a (grid) computing node over a lambda grid. The challenge is to identify concurrent routes (i.e., circuit-switched paths) in the lambda grid network, along which files should be transmitted, and to schedule the transfers of these files over their respective circuits. To address this challenge, we propose a hybrid approach that combines offline and online scheduling. The approach first constructs an offline schedule based on past profiling of transfer rates. Then, as files are being transferred, the schedule is modified online, depending on the amount of time that it actually took to transfer the files. The objective is to minimize the total time required for data aggregation. To demonstrate the effectiveness of our approach, we present experimental results using grid nodes running over an emulated lambda grid topology.