超宽带IP网络环境下的视频分组丢失修复技术研究

基于IP超宽带网络传送视频节目已经成为三网融合背景下的发展趋势。相对于传统广电运营商的同轴广播网,IP网络更加复杂,出现分组丢失的可能性更大,可能会影响用户的观赏体验。目前的视频编码技术本身的冗余机制大多适用于同轴网络,因此有必要对IP网络中的视频分组丢失修复机制进行研究。本文分析了分组丢失对视频质量的影响,并对目前主流的分组丢失修复技术进行了针对性分析和比较,结合测试结果,给出了可行的分组丢失修复技术应用建议。     

Next-generation optical networks as a value creation platform

In this article we discuss the role of the next-generation optical networks and introduce enabling technologies that support network evolution. The role of networks is undergoing change and is becoming a platform for value creation. In addition to providing new services, networks have to accommodate steady traffic growth and guarantee profitability. We envision a next-generation optical network as the combination of an all-optical core and an adaptive shell operated by intelligent control and management software suites. Possible technological innovations are introduced in devices, transmission technologies, nodes, and networking software, which will contribute to attain a flexible and cost-effective next-generation optical network. New values will be created by the new services provided through these networks, which will change the ways we do businesses and go about our private lives.     

城域网的全光分组交换

网络业务的需求不断提高,迫使网络技术发生巨大变化,在新型的网络环境下,传统开放系统互连参考模型(OSI )的网络分层已不再适用,在光层实现像交换这样越来越智能的功能已成为必然趋势。全光分组交换正是以这样一种形式出现的,它将对下一代网络产生深远的影响。文中详细阐述了全光分组交换的实现和结构,说明全光分组交换如何运用到更灵活的下一代城域网中,最后给出与之相关的使能技术的发展情况。     

Unified approaches to integrated-service networks–burst and fast packet switching

The increasing demand for communication services, coupled with recent technological advances in communication media and switching techniques, has resulted in a proliferation of new and expanded services. Currently, networks are needed which can transmit voice, data and video services in an application-independent fashion. Unified approaches employ a single switching technique across the entire network bandwidth, thus allowing services to be switched in an application-independent manner. This paper presents a taxonomy of integrated-service networks, including a look at NISDN, while focusing on unified approaches to integrated-service networks. The two most promising unified approaches are burst and fast packet switching. Burst switching is a circuit switching-based approach which allocates channel bandwidth to a connection only during the transmission of ‘bursts’ of information. Fast packet switching is a packet switching-based approach which can be characterized by very high transmission rates on network links and simple, hard-wired protocols which match the rapid channel speed of the network. Both approaches are being proposed as possible implementations for integrated-service networks. We survey these two approaches, and also examine the key performance issues found in fast packet switching. We then present the results of a simulation study of a fast packet switching network.     

On Development of Networking Technologies and Pervasive Services

Development in networking technologies is enabling services that will change our daily life and living environment. The most obvious change in our way of communicating is the increase of mobility involving not only terminals but also users and services. The key enabler is the Internet Protocol, which makes the service convergence possible, i.e., development that allows services, even network technology specific ones, to be carried over all sorts of physical networks. This paper discusses the various networking aspect that affect the service delivery as well as the services themselves.Pertti Raatikainen received PhD in information and communications technology from Helsinki University of Technology in 1996. He started his working career in Nokia Telecommunications as R&D engineer in early 1980s. In mid 1980s, he joint VTT where he held several positions: research scientist, senior research scientist and research group manager. In mid 1990s, he worked two years for Teleste Ltd. as product development manager. In late 1990s he returned to VTT and is currently acting as research professor. His research interests are focused on broadband network technologies and, especially, on switching and routing techniques.     

5G网络传输解决方案

随着网络强国战略的推进,我国5G网络加快了建设步伐,传输网作为5G网络的基础,快速重构一张满足5G业务发展需求的传输网显得非常重要,5G网络业务的差异化需求带来传输网重构,5G传输新技术手段为5G传输网重构提供了支撑,在5G传输网解决方案原则基础上进行分阶段部署及重构5G传输网络,对减少投资加快5G网络建设和保障5G基站安全运行将起到重要作用。     

Flexible Universal Networks—A New Approach to Telecommunication Services?

GPRS, WLAN integration, Mobile Number Portability and UMTS are some of the new technologies which are foreseen to carry many new service applications. In the near future, it is expected that mobile networks will go beyond connecting people and will connect an increasing number of machines, appliances, consumer devices, sensors and actuators. Also, users will connect through personal area networks and the importance of user profiles and service profiles will grow. Given the current strictness of network design, those services will further increase the complexity of today's networks. The reason is established design principles, which require new, dedicated network elements for new service applications. In addition, the applications contain their own subscriber data, usually stored locally in the application's database (distributed across the network), managed from their own management systems and with their own interfaces to Subscriber Care and Accounting Systems. In current designs, databases like home location register, AAA-Servers, MMS, Number Portability and others keep a significant amount of identical data that have to be kept consistent across all applications. For Network Operators, the effort to plan, to administrate and to introduce new services in those networks increases dramatically. This paper presents a concept to simplify current and future telecommunication networks. The concept contains a number of measures that complement each other but can be implemented independently one from another. In addition, a Telco project is presented (Evolute) where some of the ideas presented in the paper have been implemented.     

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     

Trunking of TDM and narrowband services over IP Networks

The recent interest in IP as the vehicle for transporting TDM and narrowband services stems from the possibility of using a common transport network for voice, video, and data, and the flexibility with which new services can be introduced. A key step in the evolution of networks towards a ‘broadband’ IP‐based environment is the ‘graceful’ interworking of the IP networks with the existing networks and services, particularly with the circuit switched telephone network. A ‘graceful’ interworking approach is one whose complexity is minimal and preserves the user's perceived quality of service (QoS). To interwork with a circuit switched network whose services are pre‐dominantly time‐sensitive, the IP network must essentially behave as a transparent ‘link’ in the end‐to‐end connection. This paper presents an overview of the main technical problems to be addressed when trunking TDM and narrowband services over IP networks. Copyright © 2002 John Wiley & Sons, Ltd.     

European research on future internet design - seamless content delivery in the future mobile internet

Future Internet has become the federating theme for European research on communication networks and services. At the core lies research on communication networks toward an efficient, scalable, and reliable future Internet coupled with research on the underlying technologies, in particular mobile and wireless access and optical networks. This article first presents the motivation for a bold initiative for future Internet research in Europe. In this context a changing business environment for telecommunications and the Internet, and the opportunities to provide future Internet services are discussed. From a technical perspective the limitations of the current Internet technology are outlined. The research activities that address the challenge of future Internet research are introduced under three main lines: future Internet architecture and network technologies, spectrum-efficient access to future networks, and converged infrastructures in support of future networks. Examples of the first promising approaches to significantly change the principles of the Internet architecture and protocols are presented.     

全IP网络中的业务与终端

文章认为业务发展是网络发展的驱动力量,新技术只有在更多新业务面世的情况下才能得到大力发展.但如果业务终端的基础能力不足会形成较高的业务应用门槛,有时只有在终端技术实现突破后业务才会突飞猛进地发展.文章在分析业务发展中的终端与运营链之间的相互影响的基础上,探讨了移动网引入IMS架构后对终端制造商、网络运营商的影响,并明确指出下一代网络将归于IP网络、业务将驱动网络发展.     

Can communications and sensors work together in one network?

With the development of both optical fiber-based communication and sensation, one interesting topic has been pointed out. How to connect those mountains of sensors to detect the signal in a large area, and how to make the cost of sensing system lower enough should be studied. A network of sensors is a good option. All sensing equipments, including the interrogators and the sensors, will be internetworking together. However, fiber optic communication networks have been developed very well over the past two decades. Is it necessary to rebuild a new network for sensors? In this paper, some new technologies in the two areas of fiber optic sensors and fiber optic communication will be addressed. Then, the available overlay architecture of a fiber optic sensors network will be presented. Finally, a polymorphous optical burst switching (POBS)-based architecture will be proposed, which can support all kinds of services, including digital data optical circuit/burst/packet switching and analog fiber optic sensor signal circuit/burst switching, etc.     

Mobility management in third-generation all-IP networks

It is now widely recognized that using IP as the foundation for next-generation mobile networks makes strong economic and technical sense, since it takes advantage of the ubiquitous installed IP infrastructure, capitalizes on the IETF standardization process, and benefits from both existing and emerging IP-related technologies and services. The large-scale support of data services and their integration with legacy services are the common objectives of all wireless efforts termed third generation (3G) and beyond. In these all-IP wireless networks, IP can be deployed in two modes: the transport mode and the native mode. As we show in this article, this duality in the use of IP has a significant impact on network efficiency and performance. It is the extended native use of IP in the terrestrial segment of a wireless operator's domain that more readily allows for building a converged network with multiple access technologies. We then discuss the different levels of mobility in the all-IP network. In particular, our focus is on micromobility, and on the issue of seamless localized mobility within the converged network. After reviewing the mobility schemes that have emerged in previous years, we describe a hierarchical mobility management scheme based on multiprotocol label switching (MPLS). The scheme employs an enhanced type of MPLS routers, called label edge mobility agents, and is scalable, efficient, and flexible. It directly inherits the noted capabilities of MPLS in terms of support of QoS, traffic engineering, advanced IP services, and fast restoration. This scheme does not use nodes that are specific to any given wireless technology, and is well suited for gradual deployment     

Evolution of Terrestrial Optical System and Core Network Architecture

Optical systems and technologies have been radically changing the telecommunication networks for past 15 years; today wavelength division multiplexing (WDM) technology, optical amplifiers, and simple optical switching elements like optical add-drop multiplexers (OADMs) are used in the backbone networks of all operators worldwide. Optical systems nowadays provide the basis for cost-effective transmission of large amounts of bandwidth over the Internet, and will enable its future growth and the spreading of new applications and services. This paper summarizes the main trends in optical networking and investigates potential future application areas. Optical system technology has become so pervasive in network design that it needs to be considered in the context of provisioning new applications and services. Therefore, the analysis is not limited to the aspects of physical transmission, but also takes into account recent developments in integrated network design as well as network control and management. The following sections describe the key functionalities of future optical network architectures, and the key findings of the theoretical analysis are supported by the results of a field trial of advanced transmission technology.     

Telecommunications markets, industry, and infrastructure in Korea

Following the successful deployment of basic telecommunications networks and services in the 1970s and 1980s, Korea's telecommunications sector has undergone significant environmental and technical changes. Among these are the introduction of competition in the telecommunications market, the allowance of foreign ownership of telecommunication services, and the deployment of new networks and services, all within a new legal framework. As demands for more diversified and high-quality telecommunications increase, Korea is now preparing for a major communication infrastructure that can serve as a common network foundation. Named the Korea Information Infrastructure, it is planned to provide a new network foundation that will serve as the core of the information society in the 21st century. This article describes the current status of and future perspectives on the Korean telecommunications markets, industry, and infrastructure     

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.     

Advanced internetwork design — today and in the future

This paper highlights the current approach to large-scale internetwork design using today's network layer routeing protocols. It describes how large internetworks can be constructed to provide stability, resilience and scalability, together with a set of best practice design guidelines for those involved in the planning of large data networks, highlighting the key issues to be considered. The paper looks at how new technologies are likely to enhance this design approach, in particular, how the full potential of cell switching can be realised through emerging technologies such as integrated switching and routeing. The paper concludes that the model proposed for large-scale networks based on current routeing protocols and technologies can be enhanced to make optimum use of switched WAN services such as ATM, through the use of newer routeing technologies.     

Advances in data networking

This paper highlights the current approach to large-scale internetwork design using today's network layer routeing protocols. It describes how large internetworks can be constructed to provide stability, resilience and scalability, together with a set of best practice design guidelines for those involved in the design of large data networks, highlighting the key issues to be considered. The paper looks at how new technologies are likely to enhance this design approach, in particular, how the full potential of cell switching can be realised through emerging technologies such as integrated switching and routeing. The paper concludes that the model proposed for large-scale networks based on current routeing protocols and technologies can be enhanced to make optimum use of switched WAN services such as ATM, through the use of newer routeing technologies.     

Evolution towards an ATD multiservice network

Public networks will continue to evolve in order to provide additional services and to make use of emerging technologies. This evolution is being directed toward multiservice networks which allow the cheaper introduction of new services. Asynchronous time division (ATD) techniques are preferred as the basis for implementing multiservice networks, such as LANs, because they can provide full service integration, rate adaption and the statistical multiplexing of variable bit rate services. This paper outlines some gradual evolutionary paths which are directed toward a single ATD multiservice network and could provide immediate benefits. An eventual ATD network could be expected to use short fixed length packets, a mixture of datagram and virtual circuit techniques and a mixture of switch architectures in order to most economically meet the requirements of a public network. The Orwell protocol, developed within British Telecom, provides a means of meeting the performance requirements of such a network.     

The deflection self-routing Banyan network: A large-scale ATMswitch using the fully adaptive self-routing and its performanceanalyses

Because the Internet traffic, that will be the major traffic of broadband integrated services digital networks, is bursty when cells are being switched within the multistage switching network, it has a higher possibility that multiple cells arriving simultaneously at a switching element through different incoming links may have to be forwarded along the same outgoing link. We propose a high-performance large-scale ATM switch dealing with such link contention problem. It is a new unbuffered augmented Banyan network using fully adaptive self-routing control: the deflection self-routing Banyan network. To utilize all the links of the network as alternate paths, we employ the deflection-routing algorithm in each switching element, such that cells failing to get selected for the intended link are sent along different links, in the hope that they later return, or detour the contended link and continue their journey to the destination. Cells are never dropped within the switching network, whereas the switch has no multiple cell buffers. The proposed routing is as simple as that of the generic Banyan network, and all the switch elements (SEs) have a uniform structure. To design the proposed network and its self-routing, we use the topological properties that all the SEs of the Banyan network are arranged in a regular pattern topologically. We formulate and prove these properties through an algebraic formalism. We also ran a performance analysis to provide quantitative comparison against the Banyan network and the replicated Banyan networks. As a result, we show that the new network has a far better performance and scalability than the other networks