In this paper, we focus on narrowband (NB) OFDM PLC standards and associated implementations operating in frequency bands below 500 kHz. With the emergence of the Smart Grid Automated Meter Infrastructure (AMI), an international PLC standards gap was identified requiring new technology to serve market needs for higher bitrates and increased robustness [1]. This paper provides a brief history of PLC technology alternatives and the emergence of NB OFDM PLC solutions that fill this “standards gap”. We discuss power line channel impairments (e.g., noise, impedance) that we have measured on power grids and in dwellings such as in high rise buildings [2]. These studies have influenced emerging international NB OFDM PLC standards [3] [4] and existing NB OFDM PLC solutions [5] [6]. An important topic beyond NB PLC standardization is defining how the new modems coexist with legacy PLC modems operating in the same frequency band. SGIP PAP-15 [6] has done considerable work coordinating PLC coexistence requirements with IEEE P1901.2, ITU-T G.990x standards development; and PRIME and G3-PLC Alliances. Semiconductor's role is then to provide a hardware and software platform to realize a robust communications solution that can be deployed around the world. So then another important topic addressed is computational complexity. We roughly estimate modem computations as a function of signal bandwidth. This analysis shows that NB OFDM PLC standards can be implemented in software using a simple microprocessor; and in addition the same hardware platform can be used to implement the various standards.

Generalized multiprotocol label switching (GMPLS) is being applied to optical networks as a means of moving control functionality from the management plane to the control plane, and automating lightpath provisioning and maintenance. GMPLS enables IP networks with quality of service (QoS) to be traffic engineered efficiently. However, computation of explicitly-defined paths optimizing network performance is a difficult task. Previous versions of these optimization routines have not taken path delay, including queueing delay at layer 3, into account. In this paper we present a technique for traffic engineering in optical networks that support QoS considering the traffic flows with delay QoS constraint across lambda labeling networks. The proposed mechanism would facilitate lambda label path setup with specific delay QoS requirements.

In this paper, we propose a bandwidth guaranteed multi-access protocol for broadcast-and-select WDM local networks with a star topology. The proposed protocol is based on a combination of contention and reservation mechanisms for time slotted WDM networks. Every node accesses the data channel by transmitting request packets in minislots on a separate control channel. There are two types of minislots; reservation minislots and contention minislots. Nodes repairing bandwidth guarantees, called guaranteed nodes, use reservation minislots that are assigned by the control node. The remaining nodes share contention minislots using a random access mechanism. Each node dynamically assigns data channels for the minislots successfully returned on a first-come-first-served (FCFS) basis. Then, the number of reservation minislots is allocated by the control node. The remaining minislots are used for contention minislots. The reservation minislots can guarantee a minimum bandwidth for the guaranteed nodes. The contention minislots enable on-demand services at the optical layer and achieve good fairness for the remaining bandwidth. This protocol can be implemented with a simple distributed algorithm that efficiently utilizes the data channel.

In order to support quality-of-service (QoS) for real-time data communications such as voice, video and interactive services, multiaccess networks must provide an effective priority mechanism. The context of this work is the IEEE 802.14 standard for hybrid fiber coaxial (HFC) networks which has a shared upstream channel for transmissions from stations to the headend. This work presents a multilevel priority collision resolution scheme, which separates and resolves collisions between stations in a priority order, thereby, achieving the capability for preemptive priorities. We present a set of simulation scenarios which show the robustness and efficiency of the scheme, such as its ability to isolate higher priority traffic from lower priorities and to provide quick access to high-priority requests. In March 1998, a framework for handling priorities in the collision resolution process, which adopts a semantics similar to the semantics of our scheme, was included in the 802.14 standard.

Both the IEEE and MCNS medium access control (MAC) interface specifications for hybrid fiber/coax networks share a common goal to provide a standard interface to the same anticipated services (such as cable telephony, Internet and on-line access for Web browsing, chat rooms, interactive games, local area network emulation for work-at-home applications and desktop conferencing). However the solutions offered by the two groups have little in common at the MAC layer. IEEE 802.14 chose ATM transfer as its default solution while MCNS uses a scheme that favors the delivery of variable length IP packets. Our goal in this study is to conduct a comparative performance evaluation of both IEEE 802.14 and MCNS MAC specifications. We focus on the efficiency of the two solutions in terms of contention access, ATM vs IP transfer, and adequate quality of service provision.

In order to provide quality of service (QoS) to users with real-time data such as voice, video and interactive services, the evolving IEEE 802.14 standard for hybrid fiber coaxial (HFC) networks must include an effective priority scheme. In this paper we investigate the ability of the current IEEE 802.14 specification to provide priority service and show that a preemptive scheduler is not a sufficient solution. We propose to augment the scheduler with a novel scheme for implementing priority access in an HFC random access environment. The proposed mechanism integrates a multilevel priority collision resolution system into the proposed IEEE 802.14 MAC. The scheme separates and resolves collisions between stations in a priority order. A set of simulation scenarios is presented that shows the robustness and efficiency of the protocol, such as its ability to isolate higher priorities from lower ones and provide quick access to high priority requests.

The rate-based flow control mechanism in asynchronous transfer mode (ATM) networks controls the transmission rate of available bit rate (ABR) traffic sources, based on feedback information contained in the resource management (RM) cells coming from the destination and/or the network switching nodes. While the source and destination end systems behavior are fully described in the ATM Forum Traffic Management Specification, the network switch mechanism is implementation dependent. Since there is a variety of algorithms an ATM switch vendor can choose from, different performance characteristics are expected. This paper investigates the interoperability issues in terms of network performance and fairness of bandwidth allocation when an ATM network consists of switches using different rate control mechanisms, namely, the explicit forward congestion indication (EFCI) mode and the explicit rate (ER) mechanism. Simulation results show that these algorithms will interoperate as long as the switch implementation conforms to the end system behavior for congestion notification and usage of RM cells. Moreover, the location of an ER switch in a given topology might be critical to solving the "beat-down" phenomenon, when traffic passing through a larger number of switches might get less bandwidth than single hop traffic.

Two candidate protocols for the generic flow control of the broadband integrated services digital network (B-ISDN) are currently being considered by the Accredited Standards Committee T1 (ASC T1). One proposal advocates the use of a distributed queue dual bus (DQDB)-like mechanism with a three level priority scheme. The other proposal is based on a slotted ring with control terminal equipment (C-TE), assigning periodic credit authorizations to the transmitting stations. This paper analyzes the performance behavior of the two protocols according to traffic scenarios and boundary conditions defined by the International Telephone and Telegraph Consultative Committee (CCITT) and T1.>

A general survey of theory, practice, and standardization activities of conformance testing of the protocols for the integrated services digital network (ISDN) is provided. Basic concepts of testing, development of test suites and test tools, descriptions of testing operations of major vendors, and recommendations for future activities are presented in order to provide a broad overview of conformance testing efforts.>

Summary form only given. In the area of ISDN conformance test development NIST's objective is to produce abstract test scripts independent of any test system environment, and to place these test scripts in the public domain. NIST has promoted a cooperative effort amongst interested parties in the industry and a unified conformance effort has been established in the NIU Forum. NIST will maintain a neutral position and serve as a catalyst to the development of test suites in a timely manner. It is planned that test suites for layer 2 (CCITT Q921) and layer 3 (CCITT Q931 or ANSI's equivalent) will be developed first. Currently, NIST is focused on three areas of ISDN conformance testing: a test suite for the layer 2 (LAPD) protocol, test procedures for the layer 1 (I430) protocol, and a TTCN to 'C' translator.>