基于着色Petri网的Internet电话端系统业务冲突检测

将描述端业务的LESS脚本转换为着色Petri网模型,可以为实现形式化方法检测端业务间的冲突提供基础。本文根据业务逻辑树节点的特性和LESS的定义,提出了通用的转化规则,实现了端业务的形式化建模,从而方便了业务的集成及业务间的离线检测。通过CPN Tools对建立的业务模型进行仿真并分析模型状态空间,检测出端业务之间是否存在冲突。最后,用典型的业务实例验证了所提方法在Internet电话端系统环境中的可行性和有效性。     

Integrating Internet telephony services

Cost savings and the ease of developing and adding new services have motivated great interest in Internet telephony, which integrates services provided by the Internet with the public switched telephone network (PSTN). Internet telephony relies on several protocols, including the real-time transport protocol (RTP) for multimedia data transport and the session initiation protocol (SIP) or H.323 for establishing and controlling sessions. SIP can integrate with other Internet services, such as email, the Web, voice mail, instant messaging, conference calling, and multimedia collaboration. We have implemented a SIP-based software suite called the Columbia Internet extensible multimedia architecture (Cinema), which we installed and integrated with the existing private branch exchange (PBX) infrastructure in the computer science department at Columbia University. The Cinema environment provides interoperability with the PSTN, programmable Internet telephony services, and IP-based voice mail. It also integrates Web access and e-mail for unified messaging and supports multiparty multimedia conferencing. The setup lets us extend our PBX capacity and will eventually let us replace it while keeping our existing phone numbers. It also provides an environment in which we can easily add new services and features, including interoperation with existing multimedia tools, e-mail access from standard. telephones, network appliance control, and instant messaging support     

Parlay-based service engineering in a converged Internet–PSTN environment

This paper examines current approaches to signalling and service interworking between Internet and public switched telephone network (PSTN). It notes that until now convergence between the two networks has for the most part taken place in the transport and signalling layers. Signalling interworking architectures cater for the specific class of telephony-like services and although they can accommodate the extension of the intelligent network's (IN) realm of control in the Internet, they do not provide a generic platform for service interworking. Through the adoption of the Parlay APIs, a way is foreseen for (a) consolidation of telephone service over both Internet and PSTN through the imposition of a uniform call control API while allowing the installed IN infrastructure to be used also for Internet telephony services and (b) for service interworking between telephony-like services and open distributed services in the Internet. The paper proposes a service architecture that can be used as a platform for Parlay-based service interworking while offsetting some drawbacks that the Parlay approach incurs.     

A voice over IP service architecture for integrated communications

The rapid evolution of Internet telephony has introduced new service implementation paradigms. The authors propose a service architecture that integrates circuit based telecommunications with the Internet through the control elements of traditional and emerging networks, specifically the gatekeepers of VoIP and the SCPs of PSTN     

From POTS to PANS: a commentary on the evolution to Internettelephony

A PSTN phone can generate only a small set of signaling events and tones, and cannot receive or process signaling of any sophistication. Packet phones, on the other hand, can receive and process signaling automatically and also send signaling out of band as a separate set of IP packets. Evolution from plain old telephony services (POTS) to IP telephony therefore promises some pretty amazing new services (PANS). It will nevertheless take many years to transition to a purely packet-based environment. The authors describe aspects of the evolution of telephony networks and services as they relate to the underlying changes in technology. The following technologies are mentioned: Internet telephony; intelligent networks; billing information systems; electronic commerce     

An Agent Model for the Resolution of Feature Conflicts in Telephony

Most telecommunication service providers resolve the feature interaction problem by providing specific instructions in their management software to handle scenarios where feature interaction may occur. This approach suffers from the complexity of the resulting code and the difficulty of adding new features to the system. Moreover, the system predefines the result of the resolution of the conflicting features and the end user has no means of choosing a different behavior, depending on the preferences of the user. In this paper we propose an agent-based architecture to detect and resolve feature interactions. Our system benefits from the flexibility and the semantic richness of policies and fuzzy logic to allow the end user to alter the behavior of the system, thus obtaining a more personalized service.     

Orchestrating Web Services with BPEL

Effective Web services demand careful synchronization on various abstraction levels. The Business Process Execution Language supports modeling and executing business processes from both the user and systems perspectives. In this way, Web services application developers can use BPEL to orchestrate service interactions in a global system view and to manage individual interactions based on outside events. More and more Web service providers are using BPEL to integrate their services independently of vendors and related programming languages. In this column, we introduce BPEL and presents some guidelines for using it in your Web services management.     

The impact of the Internet on telecommunication architectures

The ever-growing popularity of the Internet is dramatically changing the landscape of the communications marketplace. The two separate worlds of the Internet and Telecommunications are converging. The respective advantages of the two environments are being integrated to fulfill the promise of the information super-highways. In this paper, we examine the impact of the Internet on the main telecommunication architectures, namely the IN, the TMN and TINA. There are two new tendencies for implementing telephony services in combination with the Internet: running part of the control system over the Internet, or conveying both the user data and the control information over the Internet. We examine these two tendencies, and elaborate on possible ways of salvaging the best parts of the work achieved by the TINA-Consortium in the Internet context.     

CitiTime: a system for rapid creation of portable next-generation telephony services

We present the architecture, design and experimental research prototype implementation of CitiTime, an open system architecture for the rapid development of advanced next-generation telephony services that overcomes some of the limitations of the current closed PSTN architecture and service model. CitiTime allows communication sessions to be set up over the PSTN, the Internet, or a combination of both. Services can be provided by multiple cooperating distributed service providers, some of whom may use third-party software components which can be “plugged in” or even dynamically downloaded from the network as needed. This allows advanced services to be deployed and delivered to users rapidly, a crucial requirement in the increasingly competitive telecommunications services marketplace. CitiTime is built upon an object-oriented call model called Citi Call Control (CCC) which we have defined as a small set of extensions to the standard Java Telephony API (JTAPI) call model. JTAPI is designed primarily for centralized, single provider, call center type applications. Our extensions provide support for multiple, distributed providers as well as advanced services. CCC hides details of underlying call-state management, protocols and hardware from applications. The CitiTime prototype software is currently operational in our laboratory. We briefly describe its current implementation as well as future work to address issues such as fault tolerance.     

基于面向服务体系结构的综合业务生成

对当前主要的电信业务生成技术进行了分析,提出了一种基于SOA的综合业务生成系统框架,利用统一的服务描述和高效灵活的服务调用机制,支持网络开放能力的多种封装形式和多种业务实现环境,并把电信网络和Internet上的服务能力有机结合起来。     

A mobile-based solution for supporting end-users in the composition of services

Currently, technologies and applications evolve to create eco-systems made up of a myriad of heterogeneous and distributed services that are accessible anytime and anywhere. Even though these services can be used individually, it is their coordinated and combined usage what provide an added value to end-users. In addition, user’s wide adoption of mobile devices for daily activities have fostered a shift in the role played by end-users towards Internet data and services. However, existing solutions to service composition are not targeted to ordinary end-users. More easy-to-use tools have to be offered to end-users to make sure that they are successfully accepted and used by them. To this end, the work presented in this paper supports end-users in the creation of service compositions by using mobile devices. We present a Domain Specific Visual Language (DSVL) for end-users that allows them to create service compositions. A tool specifically designed for mobile devices supports this DSVL.     

语音电子邮件系统的设计与实现

文章设计的语音电子邮件系统（ＶｏｉｃｅＥｍａｉｌ）可以将Ｉｎｔｅｒｎｅｔ的电子邮件服务功能延伸到普通的电话系统,Ｉｎｔｅｒ－ｎｅｔ用户可以通过电话方便地查询和处理自己邮箱中的电子邮件。文章对ＶｏｉｃｅＥｍａｉｌ的核心组件语音电子邮件网关（ＶｏｉｃｅＥＭＧ）的构成和实现方法进行了详细讨论,并以ＰＯＰ３代理为例介绍了通过电话系统查询和处理电子邮件的过程。     

An architecture for residential Internet telephony service

Network gateways are used to set up calls between the public switched telephone network (PSTN) and the Internet, but existing gateways support a relatively small number of lines. To meet the scalability and availability requirements of mass-market deployment of carrier-grade telephony services, the authors propose an architecture based on the decomposition of Internet gateway functionality. The media transformation function of today's H.323 gateways is separated from the gateway control function, and intelligence is centralized in a call agent. The Media Gateway Control Protocol is introduced; MGCP is an Internet draft currently under discussion by the IETF for standardizing the interface between a call agent and the media transformation gateway     

基于工作流的电信业务开发系统模型

随着Web服务技术的发展,Web服务已经成为集成电信网、移动网、互联网上分布和异构应用的通用技术。基于流程的Web服务组合语言未考虑业务规则的分离,不支持流程中不确定的动态部分的抽象和封装,因此该文提出了将规则系统应用到工作流中的业务开发系统模型,从而为服务提供商进行电信新业务开发和生成提供了快速有效的途径。     

The Virtual Service Grid: an architecture for delivering high‐end network services

This paper presents the design of a new system architecture, Virtual Service Grid (VSG), for delivering high‐performance network services. The VSG is based on the concept of the virtual service which provides location, replication, and fault transparency to clients accessing remotely deployed high‐end services. One of the novel features of the virtual service is the ability to self‐scale in response to client demand. The VSG exploits network and service information to make adaptive dynamic replica selection, creation, and deletion decisions. We describe the VSG architecture, middleware, and replica management policies. We have deployed the VSG on a wide‐area Internet testbed to evaluate its performance. The results indicate that the VSG can deliver efficient performance for a wide range of client workloads, both in terms of reduced response time and in the utilization of system resources. Copyright © 2002 John Wiley & Sons, Ltd.     

Emerging alternatives to today's advanced service architectures for Internet telephony: IN and beyond

Two principal sets of standards are emerging for Internet telephony: H.323 from the ITU-T, and session initiation protocol (SIP) from the IETF. The advanced service architecture that comes with H.323 is rather archaic, and reminiscent of the old days of circuit–switched telephony. The one that comes with SIP is more modern, but has its share of deficiencies. While improvements are being made, alternatives are being sought. Two trends are noticeable in the search for alternatives: the return to the old and well-known intelligent network (IN) architectural framework, and the exploration of more recent approaches, such as mobile agent technology, that go beyond IN. This paper scrutinizes the trends in the search for alternatives to today's ITU-T and IETF advanced service architectures for Internet telephony. We successively review the IN-based architectures that are emerging, and the mobile agent-based architectures that are being explored. Many circuit–switched networks that adhere to the IN architectural framework have been deployed worldwide. The emerging IN-based advanced service architectures may facilitate the reuse of this installed base. They will however fall short when it comes to supporting the wide range of advanced services expected from Internet telephony. Mobile-agent-based advanced services architectures are much more promising, although the technology is not yet mature. Their inherent flexibility can easily help in exploiting to the fullest extent the host of opportunities Internet telephony brings. The return to the IN architectural framework may be economically viable in the short and medium terms. There is however no doubt that it will be imperative to go further in the long term. Mobile agent technology is certainly among the venues worth being explored for going beyond IN.     

集成化邮箱系统的设计与实现

该文提出了一个基于传统电信网（PSTN）和现代因特网（Internet）的集成化邮箱系统,从而使语音与Email得以实现通邮,这对目前我国因特网尚不普及情况下,提高电话利用率,降低通信费用,促进因特网的发展具有重要的现实意义,该设计已经在某电信公司得到实施。     

A Survey of Application Layer Techniques for Adaptive Streaming of Multimedia

Though the integrated services model and resource reservation protocol (RSVP) provide support for quality of service, in the current Internet only best-effort traffic is widely supported. New high-speed technologies such as ATM (asynchronous transfer mode), gigabit Ethernet, fast Ethernet, and frame relay, have spurred higher user expectations. These technologies are expected to support real-time applications such as video-on-demand, Internet telephony, distance education and video-broadcasting. Towards this end, networking methods such as service classes and quality of service models are being developed. Today's Internet is a heterogeneous networking environment. In such an environment, resources available to multimedia applications vary. To adapt to the changes in network conditions, both networking techniques and application layer techniques have been proposed. In this paper, we focus on the application level techniques, including methods based on compression algorithm features, layered encoding, rate shaping, adaptive error control, and bandwidth smoothing. We also discuss operating system methods to support adaptive multimedia. Throughout the paper, we discuss how feedback from lower networking layers can be used by these application-level adaptation schemes to deliver the highest quality content.     

Extending TINA with Secure On-Line Accounting Services

Concepts and principles of TINA (Telecommunications Information Networking Architecture) are introduced with the objective of correcting problems of the current centralized service control and service data model in an IN (Intelligent Network). It is becoming increasingly clear that the future sophisticated telecommunication services, e.g., multimedia, and multi-party conferencing, breaking away from the traditional telephony call model will need the solutions for rapid and efficient introduction, deployment, operations, and management.In this paper, we discuss accounting features and requirements, as well as security services in the TINA management context. We will introduce and present an implementation of a model for a security management, based on secure objects, cryptography and certificate distribution. In order to provide secure services, secure objects that have security functionality, such as authentication and access control, have been defined. Secure objects in our model are CORBA objects. The security domain is also called SBS (Security Base Server), provides security services and has an SMIB (Security Management Information Base) that contains security policies, cryptographic algorithms, and other relevant information. A prototype has been implemented and some experimental results are presented.     

网络服务定位的研究与实现

未来的互连网络中,网络服务定位将会成为多数网络业务必不可少的组成部分,网络服务定位的研究涉及一系列协议体系,论文主要讨论基于目录代理的网络服务定位体系,首先分析了IETF的服务定位协议框架、特点和局限性,然后提出一个基于轻量级目录访问协议(LDAP)的网络服务定位体系,该模型已经试验性地用于IP电话网关的定位。