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Glen Kramer

Bio: Glen Kramer is an academic researcher from University of California. The author has contributed to research in topics: Access network & 10G-PON. The author has an hindex of 3, co-authored 3 publications receiving 522 citations.

Papers
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Journal ArticleDOI
TL;DR: Incorporating wavelength-division multiplexing (WDM) in a PON allows one to support much higher bandwidth compared to the standard PON, which operates in the traditional copper-based networks.
Abstract: Feature Issue on Optical Access Networks (OAN) 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.

507 citations

Proceedings ArticleDOI
06 Mar 2005
TL;DR: This work proposes dual service-level agreements (SLAs) to enforce fairness in open access EPON and calls for further studies on how these agreements should be structured and enforced.
Abstract: "Open access" is a regulatory requirement in many countries mandating that the residential access network infrastructure be competitively available to service providers. We propose dual service-level agreements (SLAs) to enforce fairness in open access EPON.

8 citations

01 Jan 2003
TL;DR: A novel framework called Fair Queuing with Service Envelopes (FQSE), which successfully achieves both goals: it uses hierarchical control messaging to achieve scalability and it employs a concept of a service envelope to achieve farness across the entire subscriber population.
Abstract: Compared to metropolitan area networks (MANs), subscriber access networks serve a relatively small number of users and therefore are very cost-sensitive. The cost issues have prevented the deployment of optical access networks, creating a bottleneck between high-capacity local area networks (LANs) and MANS. This dissertation investigates Ethernet Passive Optical Networks (EPON), an emerging optical architecture, optimized for deployment in subscriber access networks. EPONs combine a point-to-multipoint fiber topology, variable-sized Ethernet packets, and a centralized in-band scheduling protocol to deliver subscriber's traffic at low operational cost while guaranteeing service-level agreements and ensuring fairness among the subscribers. However, EPONs present network designers with several challenges. EPON properties such as significant queue switch-over overhead, large control-plane delay, and limited control-plane bandwidth do not allow easy adaptation of existing scheduling algorithms. To efficiently allocate bandwidth in the presence of the above constraints, we propose a new algorithm called Interleaved Polling with Adaptive Cycle Time (IPACT). IPACT provides rate-proportional fair service and solves the issues of switch-over overhead and control-plane delay by interleaving the grant/request cycles of different nodes. EPON is expected to be a truly converged network, supporting voice communications, video, real-time transactions, and data traffic. To enable this multitude of applications, we extend the IPACT protocol to support multiple classes of service. We identify network conditions resulting in anomalous network behavior where the queuing delay for some traffic classes increases when the network load decreases (a phenomenon we call light-load penalty). We suggest two optimization schemes, which eliminate the light-load penalty. To operate in densely-populated areas, EPON must be scalable with the number of subscribers and maintain fairness among all the subscribers. Existing hierarchical scheduling protocols are scalable, but do not provide fairness across all the subscribers. Existing single-level protocols provide fairness, but are not scalable. We present a novel framework called Fair Queuing with Service Envelopes (FQSE), which successfully achieves both goals: it uses hierarchical control messaging to achieve scalability and it employs a concept of a service envelope to achieve farness across the entire subscriber population.

7 citations


Cited by
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Journal ArticleDOI
TL;DR: General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON.
Abstract: In this tutorial overview, the principles, advantages, challenges, and practical requirements of optical orthogonal frequency division multiplexing (OFDM)-based optical access are presented, with an emphasis on orthogonal frequency division multiple access (OFDMA) for application in next-generation passive optical networks (PON). General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON. Functional requirements are outlined for high-speed digital signal processors (DSP) and data converters in OFDMA-PON. A techno-economic outlook for such a “software-defined,” DSP-based optical access platform is also provided.

511 citations

Journal ArticleDOI
TL;DR: This paper presents an architecture and a vision for the WOBAN and articulates why the combination of wireless and optical presents a compelling solution that optimizes the best of both worlds.
Abstract: The hybrid wireless-optical broadband-access network (WOBAN) is a promising architecture for future access networks. Recently, the wireless part of WOBAN has been gaining increasing attention, and early versions are being deployed as municipal access solutions to eliminate the wired drop to every wireless router at customer premises. This architecture saves on network deployment cost because the fiber need not penetrate each end-user, and it extends the reach of emerging optical-access solutions, such as passive optical networks. This paper first presents an architecture and a vision for the WOBAN and articulates why the combination of wireless and optical presents a compelling solution that optimizes the best of both worlds. While this discussion briefly touches upon the business drivers, the main arguments are based on technical and deployment considerations. Consequently, the rest of this paper reviews a variety of relevant research challenges, namely, network setup, network connectivity, and fault-tolerant behavior of the WOBAN. In the network setup, we review the design of a WOBAN where the back end is a wired optical network, the front end is managed by a wireless connectivity, and, in between, the tail ends of the optical part [known as optical network unit (ONU)] communicate directly with wireless base stations (known as ldquogateway routersrdquo). We outline algorithms to optimize the placement of ONUs in a WOBAN and report on a survey that we conducted on the distribution and types of wireless routers in the Wildhorse residential neighborhood of North Davis, CA. Then, we examine the WOBAN's routing properties (network connectivity), discuss the pros and cons of various routing algorithms, and summarize the idea behind fault-tolerant design of such hybrid networks.

311 citations

Journal ArticleDOI
TL;DR: WDM-PON variants are proposed to be used for a unified optical access and back-hauling network to accommodate traffic growth and new applications.
Abstract: Passive optical networks are used for fiber-to-the-home/curb/cabinet/building applications. Today, two PON variants with time-domain multiple access, GPON and EPON, are being used for mass roll-outs. WDM-PONs are the next step up from these PONs to accommodate traffic growth and new applications. This article analyzes WDM-PON variants and proposes they be used for a unified optical access and back-hauling network.

232 citations

Journal ArticleDOI
TL;DR: The evolutionary path of access networks is reviewed and the drivers from technology and business perspectives for high bandwidth and low cost are shown, and Dynamic Bandwidth Allocation algorithms that allow to mitigate the effect of the increased control-plane delay in an extended-reach network are investigated.
Abstract: Long-Reach optical access is a promising proposal for future access networks. This technology can enable broadband access for a large number of customers in the access/metro area, while decreasing capital and operational expenditures for the network operator. First, the paper reviews the evolutionary path of access networks and shows the drivers from technology and business perspectives for high bandwidth and low cost. A variety of research challenges in this field is reviewed, from optical components in the physical layer to the control and management issues in the upper layers. We discuss the requisites for optical sources, optical amplifiers, and optical receivers when used in networks with high transmission rate (10 Gbps) and large power attenuation (due to large split, transmission over 100 km and beyond, and propagation), and the key topological structures that allow to guarantee physical protection (tree-and-branch, ring-and-spur). Then, some relevant demonstrations of Long-Reach Optical Access Networks developed worldwide by different research institutes are presented. Finally, Dynamic Bandwidth Allocation (DBA) algorithms that allow to mitigate the effect of the increased control-plane delay in an extended-reach network are investigated.

222 citations

Journal ArticleDOI
TL;DR: A wavelength-division-multiplexed-based passive-optical-network (PON) architecture that allows for incremental upgrade from single-channel time-division multiple-access PONs in order to provide higher bandwidth in the access network is discussed.
Abstract: We discuss a wavelength-division-multiplexed-based passive-optical-network (PON) architecture that allows for incremental upgrade from single-channel time-division multiple-access PONs in order to provide higher bandwidth in the access network. Various dynamic-wavelength and bandwidth-allocation algorithms (DWBAs) for wave-division multiplexed PON are presented; they exploit both interchannel and intrachannel statistical multiplexing in order to achieve better performance, especially when the load on various channels is not symmetric. Three variants of the DWBA are presented, and their performance is compared. While the first variant incurs larger idle times (and, hence, poor performance), the other two algorithms achieve better but different performance with critical dissimilarities. Our analysis also focuses on the fair assignment of excessive bandwidth in the upstream direction to highly loaded optical network units. We compare the performance of DWBA to another algorithm that relies on static-channel allocation. Furthermore, a study is presented wherein the number of wavelengths increases, and a comparison with interleaved polling with adaptive cycle time is shown. We use extensive simulations throughout this paper

195 citations