The (R)evolution of access networks for the informationsuperhighway

Competition in deregulated telecommunication markets forces network operators to modernize their access networks-often called the “last mile” to the customer-to provide a mix of multimedia and traditional telecommunication services. Economics necessitate an evolutionary, step-by-step approach to migrate from the present access infrastructure-composed mainly of existing telephone networks and cable TV networks-to the ultimate information superhighway. At the end of the day, however, networks of different operators should provide interconnectivity for the same set of services. A system concept is described that drives access network technology toward a “common platform” with generic access methods, cognate routing and switching, and common, standardized communication protocols. Simulation results show some performance figures of the common platform concept. An implementation on a CATV network is presented as well     

A millimeter wave broadband wireless access technology demonstratorfor the next generation Internet network reach extension

We report design and implementation scenarios for a gigabit-capacity and high-data-rate fixed wireless access technology demonstrator. The system is based on a broadband wireless access concept and implementation techniques utilizing millimeter-wave and newly introduced free-space optical wireless high-speed links. The demonstration platform is to provide broadband “last mile” access and networking solutions to Internet users in densely populated areas with homes and businesses (e.g., building-centric and inner city environments) in need of high bandwidth not served by the fiber infrastructure. The investigation focuses on the radio link design, network architecture, system integration, and a compatible interface to the existing ATM fiber and satellite core networks in support of the next-generation Internet (NGI) reach network extension by the wireless technology     

Network management for residential broadband interactive dataservices

Although coaxial networks and hybrid fiber coaxial (HFC) networks have been in use for delivering television programs to the home, their usage as access networks to provide broadband interactive data services (BIDS) to the home is very recent. In this article, the authors highlight the importance of managing the networking infrastructure for BIDS and explore the unique requirements and challenges in managing HFC networks. Considering the operational requirements of BIDS operators, network maintenance, subscriber support, and planning are identified as the three functional areas that a BIDS network management system must address. It is argued that management support built into BIDS equipment (e.g., cable modems, headend cable termination units, subscriber PCs) can provide a cost-effective way of monitoring the status and performance of HFC networks, and some initial experiences of implementing and deploying network monitors in a real-world BIDS system are presented     

Hybrid fiber/coax in the public telecommunications infrastructure

The benefits of the hybrid fiber/coax (HFC) architecture for the delivery of interactive broadband services have been widely discussed in the past few years. The cable television industry began deployment of this infrastructure in 1989 to support the broadcast video business. Recently, domestic telephone companies have looked at various degrees of HFC implementation, ranging from the delivery of broadcast video only to full telephony integration. The article looks at the HFC network evolution from a broadcast, non-essential, isolated architecture to a robust, interactive, broadband element within the public telecommunications fabric. Regional networks, interface to the public network and network management systems are a few of the significant issues with respect to the viability of HFC as the access layer to the “information superhighway.” If the HFC platform proves viable, telephone companies will adapt it to meet their needs in a fully integrated system     

MLAP: a MAC level access protocol for the HFC 802.14 network

Interactive residential broadband/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in today's cable TV (CATV) hybrid fiber/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial plants to HFC are quickly moving in this direction. MLAP is a flexible ATM-friendly MAC protocol that is capable of supporting various types of traffic with diverse quality-of-service requirements. We introduce a very versatile MAC protocol for the HFC 802.14 network. MLAP can provide integrated broadband services to the home, internetwork easily with ATM wide area networks, support QoS constraints for various types of traffic, and operate over a variety of physical layer protocols. Our presentation is only an extended summary of our medium-sharing protocol proposal to the IEEE 802.14 WG. We consider only error-free system operation. MLAP provides for the use of timers for the recovery of error situations in the network. MLAP is also supported by a management suite of protocols for management of the overall system     

Network transparency: the plaNET approach

Fast packet-switching has been chosen as the basis for future high speed, “universal” networks. The successful deployment of such networks will clearly depend on a wide range of factors such as cost and technology, but the authors believe that foremost among all is how well they will support existing and future applications. Emphasizing an application oriented perspective is one of the main motivation of the paper. The authors denote by “transparency” the ability of a network to transport application information while altering or manipulating it as little as possible, and believe it will be key to the acceptance of high-speed networks. While the concept is clearly not new, they articulate the need for it and illustrate its feasibility and the advantages it affords through the example of the plaNET network. In particular, they argue that a “transparent” data transfer mechanism can be provided that is both compatible with current standard proposals such as ATM and frame relay, and offers applications the choice of the data transfer mode that best meet their needs. A number of examples are used to illustrate these claims     

Managing the last mile [access network]

No matter how good the transmission technology, if you can not manage it, you can not use it. Telecommunications planners are faced with simultaneously provisioning the explosion of lines linking homes and businesses with central offices and planning for a future where highly sophisticated interactive broadband services must be provided. Managing all portions of the network is complicated, but none more so than the access network known colloquially as “the last mile,” the low data speed capacity lines that actually connect the home or business to the high-speed network. Before a line used for plain old telephone service (POTS), called a loop, can be used in higher speed applications it must be checked to make sure that it has the right electrical characteristics. The evolution of the loop from POTS to midband to broadband usage is examined emphasizing the relevant plant administration processes. Using today's special service administration is an expensive way to provide service. Alternates to special service provisioning are described     

A hierarchical HFC network with QoS guaranteed traffic policy

The rapid growing of the Internet makes multimedia and broadband services closer to the users. For people at home, two typical networks are available to access the Internet: telephone network and CATV network. This paper presents a hierarchical tree-based structure for the hybrid fiber-cable (HFC) network where the traditional HFC network is partitioned into segments. Each segment is coordinated by a central traffic controller (CTC). A reservation-based traffic policy is also proposed for the CTC to schedule the data transmissions within the segment to provide guaranteed QoS, such as constant bit rate (CBR) service and variable bit rate (VBR) service. The CTC also furnishes the bridging function so that local traffic within the controlled segment is filtered to save the network bandwidth. Based on the segmentation concept and filtering function, the bandwidth can be reused efficiently and the system performance is improved significantly. Simulation results indicate that the proposed hierarchical HFC network performs much better than the traditional HFC network in terms of delay, delay jitter and channel utilization. Through the proposed traffic policy, the hierarchical HFC network also offers guaranteed QoS for the users     

EPON技术提升广电网络的竞争力

网络向全IP网和光纤网转化已经是大势所趋，EPON正是这样一种全光网络。EPON采用单纤加无源光分路器的树状网络结构，和广电HFC网络的树型结构同出一辙。广电采用1550＋EPON技术抢先一步建设全业务网络，必将提高广电网络的竞争力，为广电网络事业的发展带来美好的前景。     

Considerations for ISDN planning and implementation

THE INFORMATION AGE has created such a diversity between the Communications needs of the business user and the residential Community that one common-denominator public telephone network can no longer serve everyone. The time when evolutionary network enhancements can be justified and implemented will come too late to be acceptable to a large body of business users, because of this diversity of needs. The emerging proliferation of technological bypass of local telephone facilities in the United States is symptomatic of the need for one or more shared wideband/ broadband overlay networks to serve the business community. This environment requires accelerated introduction of digital technologies in the telephone network for provision of high-speed end-to-end digital services including data, facsimile, and video. This necessitates the use of Overlay facilities and networks to meet present business customer demands until the loop plant in the common-denominator network can evolve to optimally meet the varied demands of the whole community. This paper describes past progress and current plans for the introduction of digital technologies for switching, interexchange trunking, and the local loop for an end-to-end digital network. The paper also discusses the implementation of common-channel signaling, based on CCITT's SSN07 in the circuit-switched network, as well as the use of an overlay packet-switched network for provision of data commumcations and videotex services.     

The high-speed access network

The high-speed access network will replace part or all of the local-line distribution and will become an increasingly important element of the network. The network operator will wish to provide the full range of broadband and narrowband services to end users connected to the access network. To ensure that these can be delivered by the access network to end users in a consistent and standard manner and to allow interoperability of access networks and local exchanges, it will be necessary for the suppliers of access network equipment to support ETSI V5.1, V5.2 and V_b5 interfaces. This tutorial paper describes the fundamental principles and key functional capabilities of these interfaces     

QoS-enabled broadband mobile access to wireline networks

Third-generation wireless systems, known as IMT-2000 within the ITU, offer opportunities to support a wide range of multimedia services. Packet data services will play a major role in these new multimedia services. A key component of packetized data services is to ensure end-to-end QoS requirements through efficient management of the network's resources. We present an overview of radio resource scheduling schemes including architecture, radio interface protocol, and interactions in a wideband CDMA environment. We then present an example of the QoS architecture followed by a discussion on end-to-end provisioning and interworking from wireless to fixed networks     

The application of optical packet switching in future communicationnetworks

Telecommunication networks are experiencing a dramatic increase in demand for capacity, much of it related to the exponential takeup of the Internet and associated services. To support this demand economically, transport networks are evolving to provide a reconfigurable optical layer which, with optical cross-connects, will realize a high-bandwidth flexible core. As well as providing large capacity, this new layer will be required to support new services such as rapid provisioning of an end-to-end connection under customer control. The first phase of network evolution, therefore, will provide a circuit-switched optical layer characterized by high capacity and fast circuit provisioning. In the longer term, it is currently envisaged that the bandwidth efficiency associated with optical packet switching (a transport technology that matches the bursty nature of multimedia traffic) will be required to ensure economic use of network resources. This article considers possible network application scenarios for optical packet switching. In particular, it focuses on the concept of an optical packet router as an edge network device, functioning as an interface between the electronic and optical domains. In this application it can provide a scalable and efficient IP traffic aggregator that may provide greater flexibility and efficiency than an electronic terabit router with reduced cost. The discussion considers the main technical issues relating to the concept and its implementation     

Data-flow in mobile edge computing networks: end-to-end performance analysis using stochastic network calculus

Mobile edge computing (MEC) networks can provide a variety of services for different applications. End-to-end performance analysis of these services serves as a benchmark for the efficient planning of network resource allocation and routing strategies. In this paper, a performance analysis framework is proposed for the end-to-end data-flows in MEC networks based on stochastic network calculus (SNC). Due to the random nature of routing in MEC networks, probability parameters are introduced in the proposed analysis model to characterize this randomness into the derived expressions. Taking actual communication scenarios into consideration, the end-to-end performance of three network data-flows is analyzed, namely, voice over Internet protocol (VoIP), video, and file transfer protocol (FTP). These network data-flows adopt the preemptive priority scheduling scheme. Based on the arrival processes of these three data-flows, the effect of interference on their performances and the service capacity of each node in the MEC networks, closed-form expressions are derived for showing the relationship between delay, backlog upper bounds, and violation probability of the data-flows. Analytical and simulation results show that delay and backlog performances of the data-flows are influenced by the number of hops in the network and the random probability parameters of interference-flow (IF).     

Information infrastructures and multimedia communications:different approaches of the telephone, data, and radio/TV worlds

Information infrastructures and multimedia communications are necessary prerequisites for the future information society. Approaching the multimedia world of tomorrow, the telephone world, the data world, and the radio/TV world of today will overlap to a growing extent. This is true for utilization and technology as well as for market and competition. There will more likely be an application revolution; however, for networks-and partly for services and terminals, too-it has to be an evolution. Among others, ISDN and later ATM networks are expected to contribute to efficient information infrastructures and multimedia communications. The article discusses overall concepts for office, home, and travel; end-to-end solutions, including the intelligence and management needed (full-service and application-ready networks); and suitable standardization of architectures, building blocks, and platforms. For the transfer toward the information society, many political and legal problems have still to be solved on a national and international basis, in addition to technical and economical aspects. The immense upheaval, at least, asks for some common vision and some joint action through pragmatic cooperation of the parties involved     

以EPON技术促进广电网络双向改造

利用EPON技术实现有线电视双向网络改造具有明显的优势,广电网络EoC可以在一根同轴电缆上同时传输电视和双向数据信号,大大简化HFC网络的双向改造,可利用现有的HFC网络提供数字电视、互动电视和宽带服务,使广电网络具备多业务运营能力。     

QoS-aware TDMA for end-to-end traffic scheduling in ad hoc networks

The proliferation of low-cost broadband air interfaces has paved the way to the introduction of high-definition multimedia services in mobile and wireless networks. The cost for network resources utilization, when provisioning such services, will play a prominent role in their commercial success, since the more spare resources that can be used, the more cheaply the services can be delivered to the end users. In the context of promoting the role of ad hoc networks as service platforms for high quality multimedia applications, this article first discusses and classifies a set of issues involved in quality of service (QoS) provisioning in ad hoc networks and then presents a congestion-free TDMA algorithm for end-to-end network resources assignment via an optimized mechanism that relies on capacity requests and grants. The article also illustrates a method for invoking this algorithm to achieve efficient end-to-end QoS provisioning and concludes by showing the superiority of the proposed algorithm, as compared to other recently proposed TDMA scheduling algorithms     

Toward management systems for emerging hybrid fiber-coax accessnetworks

Advances in networking and hardware are motivating the development of high bandwidth local access networks that connect subscriber communities to the Information Superhighway. Hybrid fiber-coaxial (HFC) technology is emerging as one of the few economical viable technologies for designing new local access networks. These HFC local access networks are expected to support a variety of services in different spheres in an integrated manner, by drawing upon diverse technologies from the cable, computer, and telecommunications industries: the tree-and-branch network topology is typical of the cable network; intelligence in the end devices is a characteristic of the computer industry; and addressability, global interconnectivity, and quality of service (QoS) are characteristic of the telecommunications industry. It is this combination of diverse services and technologies that poses fundamental challenges in architecting a management system for HFC networks. The design of a management framework for HFC access networks is discussed     

High-altitude platforms for wireless communications

The demand for high-capacity wireless services is bringing increasing challenges, especially for delivery of the “last mile”. Terrestrially, the need for line-of-sight propagation paths represents a constraint unless very large numbers of base-station masts are deployed, while satellite systems have capacity limitations. An emerging solution is offered by high-altitude platforms (HAPs) operating in the stratosphere at altitudes of up to 22 km to provide communication facilities that can exploit the best features of both terrestrial and satellite schemes. This paper outlines the application and features of HAPs, and some specific development programmes. Particular consideration is given to the use of HAPs for delivery of future broadband wireless communications     

基于Cable Modem技术的VoIP话音解决方案

目前,一些大、中城市的有线电视公司已经拥有庞大的有线电视宽带用户群,而基于HFC网的VoIP系统正是目前在有线电视宽带网条件下综合接入语音、数据和多媒体业务的最佳解决方案之一,其中语音业务可利用中继媒体网关设备完成媒体流转换,并通过标准的E1协议接入PSTN网络,以达到充分利用HFC及PSTN网络资源迅速开展话音业务的目的.同时,作为NGN(下一代网络)中的标准部件,VoIP是面向未来、可持续发展的解决方案之一,在有线电视宽带网所及之处,可以为商业和家庭用户提供质优价廉的IP语音服务.