Integrated network and service management for the NCIH

To support the North Carolina Information Highway network and its services, GTE has developed new capabilities for the integrated management of broadband networks. These include: functionally integrated network management, enabling GTE to monitor and control ATM, SONET, and other related networks in real time, these capabilities are provided by the TelOps Network Integrated Control System (TONICS); and automated service management, enabling GTE to provide service-level configuration and fault management for new broadband services, these capabilities are provided by the broadband service management system (BSMS). Together, TONICS and BSMS provide a complete and integrated solution for managing broadband networks such as the NCIH     

A hybrid architecture for analog video broadcast and B-ISDNservices in customer premises networks

The use of SCM (subcarrier multiplexing) transmission to deliver broadcast analog video signals within a CPN (customer premises network) as an overlay to an all-digital B-ISDN (broadband integrated services digital network) is considered. The feasibility of a proposal where the analog and digital signals are carried on different wavelengths is shown. An architecture for an optical CPN, termed H-Bus and incorporating emerging broadband SONET and ATM (asynchronous transfer mode) standards, is taken as a baseline for the delivery of switched digital, two-way voice, data, and video services. An optical overlay for the distribution of analog, broadcast video services using subcarrier multiplexing is considered. Several key alternatives associated with the delivery of broadcast video services are assessed, including signal quality, number of simultaneous channels, number of user terminals to be served, and modulation format. These issues are considered in terms of their impact on the interface with the public local exchange network and on the complexity, topology, and cost of the CPN     

Integrity of public telecommunications networks

Provides an overview of the special issue of the IEEE Journal of Communications, Volume 12, Number 1 (January 1994) which addresses open questions in network integrity, reliability and survivability. Current progress in this area is discussed. The questions addressed include user survivability perspectives on standards, planning, and deployment; the analysis and quantification of network disasters; survivable and fault-tolerant network architectures and associated economic analyses; and techniques to handle network restoration as a result of physical damage or failures in software and control systems. Special interests are devoted to the survivability of broadband networks employing the new transport/switching techniques based on the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards due to their emerging role in future B-ISDN. Network integrity due to failures of common channel signaling (CCS) systems is also very critical. The present special issue includes 22 papers and is organized into the following sections: user perspectives and planning, software quality and reliability, network survivability characterization and standards, network restoration for SONET networks, network restoration for ATM networks, traffic effect and performance enhancement for computer networks, and survivable network design methods. Network restoration methods for SONET, ATM, and computer networks correspond to those for the physical layer (SONET), ATM layer, and the network layer, defined in the CCITT broadband ISDN layer structure     

Design and characterization of an error-correcting code for theSONET STS-1 tributary

The authors have designed and characterized a single-error-correcting (SEC), double-error-detecting (DED) code applicable to the STS-1 SONET format. They show that if two of the presently unallocated bytes in the path overhead field of STS-1 are assigned for error-correction coding (ECC), a {6208, 6195} shortened extended Hamming code can be implemented using as few as 660 gates plus a 1-kbyte RAM IC, achieving (O8.6×10^-3 P ₂²) BER reduction with 139 μs of signal delay. The authors explain how the existing BIP-8 error-monitoring byte of the STS-1 format could be integrated with the proposed ECC so that a net allocation of only one new STS-1 overhead byte is required for both error monitoring and error correction. The implementation method is such that all path, line, and section overhead functions in SONET can be performed at intermediate sites without requiring ECC decoding. The authors consider application alternatives and describe the forward-error-correction (FEC) circuit design and trial results. System issues are covered, including network delay, effects of error extension on BER, addition of double-error detection, performance monitoring, and options for intelligent network control and management of FEC functions. Codes related to their path-level design that are applicable to a number of other strategies for applying FEC in SONET are presented     

宽带数据网测试卡

详细介绍了一种宽带数据网络测试卡的硬件设计方法、各硬件模块功能、SDH（同步数字体系）层和ATM／POS（异步传送方式／帧传送方式）层测试功能的实现方法。这种测试卡对于宽带SDH／SONET（同步光网络）光纤网络的运营维护和网络设备的开发能够起到重要的作用。     

End-to-end survivable broadband networks

Within the EC-sponsored RACE program, the IMMUNE project was established to analyze and specify appropriate strategies for introducing end-to-end survivability into corporate and public broadband networks to support these strategies by proper techniques and evaluation tools, and to demonstrate distributed restoration on PSN (public switched networks) and CPN (customer premises networks) laboratory models. The first objective was to define a set of survivability requirements and metrics to be used in the rest of the project. This has led to the identification of a range of survivability strategy options ann how they can be mapped onto user, service provider and operator requirements. The next step on the road to integral survivability is designing and planning survivable networks, and the evaluation of the restoration and protection mechanisms that will be applied in these networks. An overview is given of this part of the project. Most protection and restoration mechanisms operate within a single network layer and network part, autonomous from network management. The interaction of mechanisms in different network layers or in different network parts, and the role of network management, are discussed. For the demonstration lab models, two techniques have been selected for implementation: a distributed restoration mechanism for a meshed ATM PSN, and a CPN ATM ring protection switching mechanism. These techniques are described and an overview is given of the ongoing activities within the IMMUNE project, with a summary of the status of the demo models     

Network design sensitivity studies for use of digital cross-connectsystems in survivable network architectures

Provides the results of an economic study on the use of SONET digital cross-connect systems (DCS) to provide survivable transmission network architectures in local exchange networks. Three fundamental survivable transmission technologies are considered: (1) a SONET self-healing ring, (2) a SONET point-to-point fiber system with 1:1 automatic protection switching and diverse routing of protection facilities, and (3) a DCS mesh with automatic DCS restoration (rerouting) protection. These three technologies are used in various combinations to form six survivable network alternatives for evaluation. Two local exchange carrier (LEC) networks are used (a 15 node network and a 53 node network) and demand, network connectivity, and unit equipment cost sensitivities are evaluated on these alternatives. In addition, the survivability of each alternative in the event of a major node failure is calculated. The motivation for the study is to determine the viability of DCS-based survivable network architectures and, in particular, the viability of SONET DCS with integrated optical terminations. The study has two objectives: (1) given a specific survivable network technology, under what conditions is it economical to place a broadband DCS (B-DCS) in a central office as opposed add-drop multiplexers (ADM); and (2) which survivable technologies with B-DCS are economical, and under what conditions. The authors conclude that the most cost-effective networks consist of “hybrids” of SONET point-to-point, ring, and mesh technologies, and that the B-DCS is economically viable for interconnection between these technologies     

Survivable virtual concatenation for data over SONET/SDH in optical transport networks

Next-generation SONET/SDH technologies-namely, generic framing procedure, virtual concatenation, and link-capacity-adjustment scheme-enable network operators to provide integrated data and voice services over their legacy SONET/SDH infrastructure to generate new revenue. An important open research problem on data over SONET/SDH (DoS) is survivability: SONET automatic protection switching is too resource inefficient for data services, and the protection mechanisms of data networks are too slow for mission-critical applications. We propose two approaches for provisioning survivable DoS connections. Our approaches exploit the tradeoff between resource overbuild and fault-recovery time while utilizing the inverse-multiplexing capability of virtual concatenation to increase backup sharing. Our results show that one approach achieves low resource overbuild and much faster fault recovery than that of data networks, and the other approach achieves fast fault recovery comparable to SONET 50-ms protection (for typical U.S. backbone networks) while still achieving modest backup sharing. We further investigate the tradeoff between network blocking performance and network control and management complexity resulting from the number of paths M a connection can be inversely multiplexed onto: larger M leads to more freedom in routing and better network performance but increases network control and management complexity. Our results indicate that the network blocking performance for small values of M (e.g., M=2 for some representative backbone network topologies) is almost as good as the case in which M is infinity.     

Plans and considerations for SONET deployment

A perspective is given from the local exchange carrier (LEC) viewpoint on the advantages of deploying SONET (synchronous optical network), the rate at which SONET will be deployed, some typical early applications and architectures, and the role SONET will play in the evolution of the LEC network of the future. The SONET deployment timeline and capabilities are examined. Aspects of SONET architecture are discussed, namely, the access network, the interoffice transport-network, and SONET operations and control. New network capabilities and services and evolution to broadband are considered     

The infrastructure for gigabit computer networks

The key features of the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards for the broadband integrated services digital network (B-ISDN) public network, which is expected to provide a powerful and ubiquitous infrastructure to support the emerging gigabit-per-second data and multimedia applications, are reviewed. The advantages of ATM, the ATM cell format, the B-ISDN protocol reference model and the ATM layer, the ATM adaptation layer, and ATM traffic management and signaling are discussed. An experimental high-performance parallel interface (HIPPI)-ATM-SONET interface is presented as an example to illustrate how the SONET and ATM techniques can be used to provide end-to-end transport for applications requiring a bandwidth of 800 Mb/s and possibly 1600 Mb/s     

Service applications for SONET DCS distributed restoration

This paper determines the scope of network applications and services that could be offered using a SONET DCS-based self-recovering mesh architecture with distributed control. The study includes an outage impact analysis on network services and a determination of how network restoration time objectives will affect the applicability for the distributed controlled DCS network architecture. It is concluded that using SONET DCS distributed control architectures to provide more complete survivability of a network would support numerous applications. Future services will demand a fault-tolerant network with complete survivability; this may only be reached through integration of SONET DCS distributed control architectures with other survivable architectures such as cell relay networks (e.g., supporting SMDS) and self-healing rings     

Performance comparison of OBS and SONET in metropolitan ring networks

This paper explores the feasibility of deploying optical burst switching (OBS) in metropolitan area networks (MANs) as an alternative to synchronous optical network (SONET), over wavelength-division multiplexing. We present a comparison between two OBS architectures (with centralized and distributed scheduling schemes), SONET, and next-generation SONET (NG-SONET), respectively. We quantify some of the performance metrics such as end-to-end delay and loss rate when supporting Ethernet traffic in metro ring networks. Our simulation results show that OBS offers significant performance improvement over SONET and NG-SONET. In general, the OBS architecture with distributed scheduling has a superior delay performance, whereas the OBS architecture with centralized scheduling has a better loss metric.     

The ATM layer chip: an ASIC for B-ISDN applications

The authors describe the architecture of an experimental research prototype application specific integrated circuit (ASIC) designed to serve as a generic building block of the future broadband integrated services digital network (B-ISDN). The chip performs common asynchronous transfer mode (ATM) layer functions such as cell assembly and cell disassembly. A new media access control (MAC) protocol developed for a broadband customer premises network is also integrated in the chip. The chip interfaces to the B-ISDN through a synchronous optical network (SONET) synchronous transmission signal-3c (STS-3c) framer chip. The ATM layer chip has been designed using 1.2 μm CMOS technology with a die area of 5.4×5.4 mm² and approximately 27000 transistors. Experimental results are described. At the user network interface, the chip can be used to implement broadband terminal adaptors and the network termination. At the broadband local exchange, the chip can be used in the implementation of ATM statistical multiplexers, ATM switch port controllers, etc     

2.5Gb/s SDH/SONET传送开销处理器芯片实现

设计了一种2.5Gb/s同步光纤网络SDH/SONET中传送开销处理器芯片.采用双向4路总线流水线结构,77.76MHz的系统时钟,即可实时处理2.5Gb/s的SDH/SONET数据.支持STM-16、4路STM-4和STM-1的再生段开销和复用段开销处理以及STS-48、4路STS-12和STS-3的段开销和线路开销处理.采用TSMC 0.13μm工艺流片,电路规模约48万门,技术指标符合ITU-T标准.     

Managing SONET equipment

The initial deployment of SONET products in the network has raised the issue of how to manage bandwidth allocations and use network management features to support existing and future network services. The requirements for managing the new transport with the features available, using management systems in existence today, are addressed. It is concluded that SONET will require new solutions in managing tomorrow's, networks, and that operations systems must develop a graceful migration plan in managing the existing and new networks     

SONET ring applications for survivable fiber loop networks

Synchronous optical network (SONET) self-healing rings (SHR) are studied in the loop environment. SONET SHR architectures for loop feeder networks are discussed, focusing on three possible dual central office (CO) architectures for fiber loop networks, using SONET SHRs to reduce network costs and provide network service survivability. These architectures reflect an integrated planning concept for SONET networks that eliminates the boundary between the access network and the inter-office network. It is shown that the use of SONET SHRs makes it easy to evolve to a protected dual CO access architecture. Economic and survivability studies are discussed. The economic studies show that using the ring approach yields significant advantages over the traditional diverse protection approach in terms of cost and survivability, especially for the dual CO architectures     

Concurrent Support of Higher-Layer Protocols over WDM

To satisfy the severe requirements involved in future communication networks, commercial and research interest in the applicability of wavelength division multiplexing (WDM) is growing. However, since WDM is merely concerned with transmitting bits over optical fibers, full advantage can only be taken when WDM is efficiently supported by higher-layer protocols. Functionality of higher-layer protocols that could be used in conjunction with WDM originates from synchronous digital hierarchy (SDH) or synchronous optical network (SONET), asynchronous transfer mode (ATM), and the internet protocol (IP). To provide flexible use of services with different levels of quality, various higher-layer protocols may directly support WDM simultaneously by reserving wavelength channels for a specific supporting protocol. Focussing on aspects of network management, this paper investigates how the mentioned higher-layer protocols may concurrently support WDM.     

Customer premises networks of the future

B-ISDN based on ATM technologies is expected to offer enhanced and sophisticated services to users, but selecting a graceful migration path is critical. During the introductory stage of the ATM-customer premises network (CPN)-as an initial broadband public network service-ATM leased-line service will use VP crossconnect network. An efficient CPN interconnection via end-to-end VP pipe therefore would be an attractive application. The possible migration scenario of ATM-CPN is presented, the required functions and services in future CPN are clarified for each evolutional stage, i.e., the introductory, expansion and diffusion stages, and the importance of medium-bit-rate SB interfaces is described. It is also shown that a 10 to 20 Mb/s metallic interface should be introduced as a cost-effective SB interface     

The Broadband Access Facility

The deployment of broadband access networks will revolutionise many aspects of society in the early years of the next millennium. Manufacturers, telecommunications providers and cable television operators world-wide are investing heavily on research into networks that provide broadband multimedia services to customers. BT has developed a prototype of a full service access network that can connect customers via optical fibre, digital subscriber line or radio technologies. This paper describes the physical implementation of the prototype network and the wide range of services that it can support.This prototype network, referred to as the 'broadband access facility' is enabling BT and its partners to understand the best access architectures for a given environment through practical testing. The network now serves as an experimental platform, that can be used for communicating broadband concepts, designing operational processes, developing management solutions and testing advanced applications.The full service access networks (FSAN) initiative is a collaboration involving fourteen of the world's leading telecommunications network operators and major equipment manufacturers. Its vision is to create a shared requirements specification for access systems supporting narrowband and broadband services. This common specification will mean that broadband network components can be developed for world markets, thus raising volumes and driving down unit costs. The common system specification is based around an ATM/SDH (asynchronous transfer mode/synchronous digital hierarchy) core network, with local optical fibre distribution via an ATM PON (passive optical network). DSL (digital subscriber line) systems maximise reuse of existing copper plant. The exact DSL system used depends upon where the optical system is terminated, e.g. in the local exchange, cabinet, kerb or home. Hence this broadband access system can support a range of access architectures — this flexibility is fundamental to the consensus achieved in FSAN.