Optimization of operational fiber links and interconnections for the merger of two networks

Multiple telecommunication networks create redundancy in fiber resources. Merging two networks can achieve savings in redundant fiber links. In this paper, we investigate the merge of two networks by adding fiber interconnections. A simulation model is developed for the optimization. The overall costs for various topologies are optimized with respect to different interconnection build costs. We show, by simulation and analytical results, that through the merger of two networks, it reduces more than 50% of operational fiber links. We are able to provide routing between any two nodes in the two networks. In all cases after critical interconnection build cost, only two interconnections are needed. The optimization is performed to find a Hamiltonian path that covers all the nodes in each network or to find a path that contains a maximum number of directly connected articulation nodes in different groupings. The proposed simulation model finds the optimal interconnection locations for these topologies.     

Approach to the scalability of a European multiwavelength multihop optical network

The multihop transmission technique has many promising features for large-scale multiwavelength optical networking. This paper proposes an approach to the flexibility in designing scalable multihop networks and suggests the deployment of this approach in an ongoing European research project. The general features of the ShuffleNet, an important example of multihop networks, are reviewed. It is shown that the ShuffleNet has certain inherent limitations. A new architecture, the Multi-ShuffleNet, is proposed to get around these limitations. The approach introduced thereby is that a multihop network, based on a standard interconnection pattern, such as the ShuffleNet, can be designed more easily and can perform better if broken down into a set of smaller subnetworks. These subnetworks, taken together, may have the same overall size as that of the original network. Each of them, however, may not necessarily have the same interconnection pattern. This concept is suitable for the realization of the European ultra-high capacity network, being envisioned through the framework of the COST 239 project. ©1997 by John Wiley & Sons, Ltd.     

快速以太网光纤转换器

目前在100Mbps计算机以太网中存在着100BASE_TX和100BASE_FX两大络，而光纤转换器正是实现上述两网络互连的介质转换器。讨论了光纤转换器的设计方案、系统结构和工作原理。     

Future fiber access needs and systems

BellSouth's Superhome/Superoffice fiber optic concept is the focus of this discussion of evolving communication needs and services. Existing and planned optical fiber deployment in Southern Bell's four-state area is described. The broadband services to be offered include high-speed data and full-motion video services (such as high-speed facsimile) and wide-area networks interconnection. Some of the other benefits of the Superhome/Superoffice are improved security and improved health and medical support. Ways to finance home information systems are considered     

Design of Optical Rearrangeable Nonblocking MINs Under Various Crosstalk Constraints

Optical interconnection networks suffer from the intrinsic crosstalk problem that should be overcome to make them work properly. Vertical stacking of optical banyan networks is a novel scheme for constructing nonblocking optical multistage interconnection networks (MINs). Rearrangeable nonblocking optical MINs are feasible since they have lower complexity than their strictly nonblocking counterparts. In this paper, we determine the sufficient condition for these MINs to be rearrangeable nonblocking under various crosstalk constraints. We show how the crosstalk constraint affects the design of rearrangeable nonblocking MINs and demonstrate that these networks can tolerate a stricter crosstalk constraint without increasing their hardware complexity significantly. The results in the paper will be useful in designing optical MINs with reasonable hardware cost and crosstalk level.     

Full service optical access networks: ATM transport on passiveoptical networks

Multimedia communication has become the driving force for installing broadband systems in the public network. Different alternative solutions have been presented to realize a broadband interactive access network, such as installing optical fiber or upgrading the existing copper network with ADSL for twisted pair or hybrid fiber coax for CATV networks. Among these alternatives, optical fiber access networks are seen as the most future-safe solution. Especially, passive optical networks prove to be a cost-effective way to introduce fiber into the access network. This article presents ATM-based transport on passive optical networks, starting with a current implementation of an ATM-PON (APON) system that has already been installed for various trials. It further describes the evolution of APON systems to high-splitting, long-range PONs. The increase in both number of subscribers and distance range is discussed in combination with some specific technological issues such as upstream burst mode optical amplification. Special emphasis is placed on the work carried out within the scope of the ACTS PLANET project     

A coherent OFDM switching system for flexible optical networkconfiguration

A coherent optical switching node based on the combination of a frequency conversion stage with a space switching matrix is proposed for flexible interconnection of future integrated broadband communication networks. The basic system concept is presented together with the architecture of a demonstrator, which allows one to study the functionality available in future networks. The major subsystems and components of the demonstrator are described, and experimental results concerning frequency stabilization, frequency switching, and space switching are presented     

Standardization Efforts in Fiber Optics

Experience with copper-based local area networks combined with the inherent characteristics of fiber optics is providing increased impetus for the development of fiber optic network standards. The installed base of networks that use copper wire, twisted shielded pair, and coaxial cable indicates that there will be many applications where networks will use a mix of both copper and fiber optic media. Successful standardization efforts must take this into account. There is indeed a great deal of standardization effort underway that involves fiber optic networking. Within the SAE AE9 Committee there are four standardization efforts to support the military. The IEEE (under project 802) has published four draft standards for copper-based networks and the 802.8 Fiber Optic Technical Advisory Group is studying integration of optical fibers into each of these networks. Other IEEE efforts include discussion and study of "all-fiber" networks. CBEMA is working on a token-passing ring network, and the Instrument Society of America is pursuing a mixed copper/fiber optic network implementation. Generally, requirements for fibers, sources, detectors, connectors, switches, branching devices, and other system elements are being established. This paper discusses some of the standardization efforts that are underway.     

A comparison of competing broadband in-home technologies

Connecting each house to a broadband access network represents an unprecedented opportunity to offer added-value services and broadband Internet access to residential users and expand the customer base beyond the corporate environment. Home networks, however, may be the last barrier to end-to-end multimedia service provisioning. Although a large number of houses have PCs, modems or multimedia network-enabled appliances, the majority are not equipped to support their interconnection, and most consumers are unwilling or cannot afford large-scale home rewiring. This paper reviews the available home-networking technologies and provides a comparison of the competing broadband in-home technologies. The focus is on technologies that do not require rewiring the home, either reusing the existing wiring or using wireless technology. The paper also discusses the residential gateway (RG) initiative, which provides a single point of convergence between the in-home and the access networks     

Versatile Multifiber Optical Connectivity Solution: From Concept to Realization

Multifiber interconnection technology is one of the important keys to increase package density in optical networks. We present a novel releasable multifiber optical connectivity solution from the initial concept to the functional prototypes. This connectivity solution relies on a V-groove alignment platform and a microlens array. It can, e.g., provide reliable connections between a fiber array and an active optoelectronic component array or between a fiber array and an optical waveguide device. Moreover, within a free-space propagation region, it provides access to collimated optical beams, thus enabling various light manipulation options. The microlens V-groove fabrication process makes use of a dedicated assembly station that has been designed for automation. The microlens array is positioned on the platform, aligned relative to the V-grooves, and fixed with a low-cost adhesive bonding technology. Uniform and stable low losses for fiber-to-fiber coupling via two lenses have been achieved for single-mode and multimode fibers at wavelengths of 850, 1300, and 1550 nm. This connectivity solution represents, therefore, a versatile cost-effective technology for releasable connections of fiber arrays to any other optical multiport device     

Advanced optical interconnection technology in switching equipment

Demands for increased interconnection density and higher bandwidth, coupled with stringent cost constraints of advanced wide bandwidth telecommunication switching equipment, are exhausting conventional electrical interconnection capabilities. The requirement for greater interconnection capabilities, spawned in part by the advances in integrated circuit technologies and the need for enhanced digital services, dictate that technology advancement must occur in traditional electronic packaging and/or interconnection techniques. The resolution of these technological needs is paramount for the successful competitive introduction of these systems. Presently, a “bottle-neck” occurs at the board-to-board level of the interconnection hierarchy. Therefore, an opportunity exists for the development of new optical interconnection techniques which can be incorporated into system designs beginning at this interconnection level and beyond. The strategic insertion of optical interconnection technology into these electronic processing systems not only meets projected performance requirements, but potentially offers them at a competitive cost. This paper describes some of the new optical strategies switching equipment designers are incorporating into today's products. These strategies range from optical data links to an implementation of a flexible optical backplane called OptiFlex     

A total-cost-of-ownership analysis of l2-enabled WDM-PONs - [Topics in optical communications]

Next-generation access networks must provide bandwidths in the range of 50-100 Mb/s per residential customer. Today, most broadband services are provided through copper-based VDSL or fiber-based GPON/EPON solutions. Candidates for next-generation broadband access networks include several variants of WDM-PONs. The total cost of ownership of these solutions is determined mainly by operational expenditures, where the cost of energy is one of the major contributors. We show that a combination of WDM-PON with active L2 switching can minimize the total cost of ownership while at the same time offering the highest scalability for future bandwidth demands.     

Wavelength rearrangeable and strictly nonblocking networks

The concept of rearrangeably and strictly nonblocking space division networks is extended to the wavelength dimension, resulting in a new family of interconnection network called wavelength-space division switches (WSDS). The complexity and wavelength assignment in these networks are discussed with some examples.<>     

电信发展阶段的网间接续费

世界各国电信体制的改革，使电信业从垄断走向竞争，由此相发的现有公司电信网和新公司电信网的网间接续费问题成了电信主管部门面临的重要课题。本文合成阐述了网间接续费的概念及内涵，特别强调了处于发展阶段的电信网和网间接续费的特点。     

Multilevel fault tolerance in infrastructure‐oriented wireless networks: framework and performance evaluation

Significant advances have been made in the design and implementation of dependable systems and networks over the last several years. However, many wireless networks have not been designed for highly dependable operation owing to network cost and complexity, and a lack of regulatory requirements on wireless service quality. One way to address this significant challenge is by introducing fault tolerance; however, very limited work has been done so far in the fault‐tolerant design of wireless networks. In this paper, we address how to utilize fault tolerance in the design of infrastructure‐oriented wireless networks. More specifically, an architectural design scheme is presented for multilevel fault tolerance using adaptable building blocks. The scheme utilizes ‘selective’ redundancy at component, link and block levels and a fault‐tolerant architecture for interconnection of building blocks. The design scheme has been implemented in both analytical and simulation models. The detailed performance results show that fault tolerance at component, link, block, and interconnection levels can significantly improve the overall dependability performance. One interesting observation is that, to achieve highest dependability, fault tolerance at link, component or block level is not sufficient and must be combined with the interconnection level fault‐tolerance. Copyright © 2006 John Wiley & Sons, Ltd.     

Commercial, legal, and international aspects of packet communications

Packet switching technology emerged rapidly in the 1970's as another viable mode of communications switching, along with circuit and message switching. Since packet switching offers economical and versatile data communication capabilities in a multiuser environment, it is particularly well suited for furnishing public data communication network services. Public packet networks are now established or being developed in most industrialized countries, and the introduction of these networks has raised policy issues relating to the structure and regulation of the national networks, and the interconnection of national networks into an international packet switching system. This paper reviews these issues and concludes that public packet switching network services will continue to be regulated in all cases; that competitive packet networks will coexist in the U.S. and in Canada, but that only one national packet network will exist in each of most other countries; that packet networks will aggravate the problem of distinguishing nonregulated data processing services from regulated data communication services; that international interconnection of public packet networks based upon CCITT standanh will occur rapidly over the next several years; and that a unified international packet switching system will eventually emerge similar to today's international telephone and telex systems.     

Optical fiber interconnection for the scalable parallel computingsystem

In this paper, we discuss the optical fiber interconnection technologies applied in the two types of parallel processing systems: 1) a backplane interconnection in a parallel processor array system and 2) a computing cluster network. We have set up a parallel processor array system using optical fiber to make point-to-point interconnection between processor elements and are developing a low-cost virtual parallel optical fiber interconnection link (VPOFLink) complying with peripheral component interconnect (PCI) local bus specifications for the computing cluster. VPOFLink is integrated with the popular PCI bus interface in order to make the link hold the same bandwidth as that of the PCI bus. It was fabricated as an available peripheral device that can been inserted into the bus slots of commercial computers directly and can operate under the control of PCI bus. Also in this paper, we demonstrate the optical fiber link for a ring network and the architecture of the ring network     

Interworking Solutions for a Two-Level Integrated Services Local Area Network

A new generation of integrated services local networks (ISLN's) is needed to yield to local area users the provision of voice, data, and images in a cost-effective manner. Besides high-speed and service integration features, these advanced multiservice communication systems have to also provide powerful interconnection with both public networks and traditional LAN's. So conception and design of the interconnection units, i.e., gateways and bridges, have to be carried out contextually with the network architecture definition. The paper addresses the interworking solutions adopted for a local integrated optical network (LION) currently under development. The architecture of bridges and gateways allowing users belonging to different LION subnetworks to communicate with public networks and commercial systems is also described. In particular, the interconnection with the integrated services digital network (ISDN) is highlighted.     

TMN-based broadband ATM network management

ATM has rapidly transitioned from a standards and prototyping concept to become the next-generation switching technology used in products available on the market. With the rapid introduction of ATM switches into networks, there is an urgent need to manage them. The article discusses the telecommunication management network (TMN) interfaces being defined for management systems to communicate with ATM network elements (NEs) and other management systems. ATM management systems will have to communicate with ATM NEs in their jurisdiction using TMN interfaces. Networks will usually contain equipment from different suppliers. Thus, it is vital that there be standard management interfaces so that these different NEs can be managed. Some standard interfaces for ATM networks are defined, while others are being defined. The status of these interfaces is reviewed in the article. Communication between different networks is also needed, both between public networks and between public and private networks. Management personnel of one network need to exchange information with other networks for certain functions (e.g., initial service provisioning), and so management systems of different networks will exchange information through a combination of mechanized and manual interfaces. The status of these interfaces is also reviewed in the article     

Optical Interconnection Networks for Terabit Packet Switches

The challenge of building packet switches with terabit capacity is being met by wavelength division multiplexing (WDM) where the benefits of optical fiber are exploited. Two kinds of WDM-based bufferless optical interconnection networks are proposed in this paper to interconnect multiple electronic packet switch modules. One is based on 3-stage Clos principle and the other is based on broadcast-and-select principle. The proposed optical interconnection networks are implemented with small modular structures to provide capacities in the range of terabit per second. Their architectures, component and interconnection complexity, and power budget analyzes are presented. In addition, the crosstalk caused by the finite ON-OFF ratio of semiconductor optical amplifier is discussed. Bit error rates with respect to different ON-OFF ratios and extinction ratios are also evaluated. It is concluded that it is feasible to implement optical interconnection networks by using state-of-the-art WDM technology, and they are excellent candidates for future terabit packet switching systems.