一种支持IP电话增值业务提供的分布业务体系结构

作为一种在PSTN中得到成功应用的技术,IN将在IP电话增值业务提供中具有重要的地位。但是当前的研究侧重于通过网关实现IN与Internet的互通,这种方案的不足之处在于沿袭了传统IN集中控制的缺点。该文的重要贡献在于重新定义了IN的概念模型,提出了一种适应于IP电话环境的分布IN体系结构,探讨了将网守扩展为SSP技术途径,并通过具体被叫付费业务的实现证明了该方案的可行性。研究表明,这种基于代理的业务结构能有效地克服了原有IN结构的缺陷,在分布控制、灵活性、客户化等方面有很大的优越性。此外,我们的方案还能与已有系统综合,具有良好的演进性。     

Mobility management alternatives for migration to mobile Internet session-based services

Session-based Internet protocol (IP) applications, such as Internet telephony, are an important component of the emerging mobile Internet. The ubiquitous availability of these services is critical to the success of the mobile Internet. Because all-IP networks will be deployed in phases and current mobile telecommunication systems will be in operation for decades to come, the interworking and migration between current network services and all-IP services is a key problem. In this paper, we address seamless roaming for session initiation protocol-based services across current cellular telecommunication networks and emerging all-IP wireless networks, such as those using third-generation and WiFi networks. We present an abstract mobility model, and map this model to three basic approaches for supporting seamless mobility: a master-slave approach, a federated system, and a unified approach. We discuss the challenges and implementation of an instance of the unified mobility management approach, called the Unified Mobility Manager, and then compare the tradeoffs of the three systems using a comparative performance analysis. We conclude that unified mobility management is most efficient if a great deal of interworking is required, and as more users invoke IP-based services; the federated approach is efficient when a single network technology is dominant and data access is limited, but requires sharing of data across networks; the master-slave approach is the least efficient, but is easy to introduce if the number of network types is small.     

Networking of networks: interworking according to OSI

The formal method of interworking networks in accordance with the overall open systems interconnection (OSI) effort being pursued by both the International Organization for Standardization (ISO) and the International Telegraph and Telephone Consultative Committee (CCITT) is described. The problem is introduced, the applicable OSI concepts are defined, and the basic architectural model for interworking and the resulting requirements on protocols, relaying, addressing, and routing are discussed. The problem of interworking from the perspective of the bottom four layers of the reference model (RM)-OSI is approached in a heuristic and informal fashion. The necessary background material is presented using a rigorous set of tools is developed by the work on the RM-OSI. The concepts of interworking are further developed. Conclusions and observations concerning ongoing work are presented     

Hiperlan/2 Public Access Interworking with 3G Cellular Systems

This paper discusses some of the recent work within the Broadband Radio Access Network (BRAN) project of ETSI (European Telecommunications Standards Institute), regarding the issue of establishing an interworking solution between Hiperlan/2 and 3G cellular systems and introduces the concept of Hiperlan/2 Public Access. So far the BRAN project has identified several fundamentally different types of possible solutions whose differences lie within the level of integration. The most essential requirements identified were authentication, mobility between Hiperlan/2 and 3G, service continuity, and preservation of the applied security levels. Recent agreements between ETSI, IEEE and MMAC may now take this work forward to produce a generic WLAN to 3G and external networks interworking standard. Indeed such work may also form the precursor for post 3G systems.     

Designing the interworking of terrestrial and satellite IP-basednetworks

The design of effective interworking between a multimedia terrestrial backbone and a satellite access platform is a key issue for the development of a large-scale IP system designed for transporting multimedia applications with QoS guarantees. This article focuses on the design of a gateway station that acts as an interworking unit between the two segments of the systems. The guarantee of differentiated QoS for applications within the envisaged global IT system is achieved effectively by assuming that the IP IntServ model in the satellite access system is combined with a DiffServ fixed core network, in which the RSVP aggregation protocol is implemented. Thus, the design activity of the IWU mainly focuses on the following issues: seamless roaming between the two heterogeneous wireless and wired environments, efficient integration between the two IP service models (IntServ and DiffServ), and suitable mapping of terrestrial onto satellite bearer for traffic with different profiles and QoS requirements     

下一代网络的业务互通体系结构

以IP为基础的因特网的出现对传统的电信网络带来了巨大的冲击,它的开放性和业务的灵活性为电信网进一步的发展指出了一个方向.但是,由于IP在提供具有质量保证的等级业务方面缺乏技术的保障;局域网技术、广域网技术的发展使得原来被认为功能简单的第二层传输网络具有越来越强的业务能力,例如QoS、多播、VPN以及安全管理能力,将导致多接入、多业务的下一代网络端到端业务控制和业务集成越来越复杂,使得我们需要重新审视网络互连和业务集成的基本思路,建立下一代网络的新的业务概念.本文对这个问题进行了初步的探讨,结论是:下一代网络具有新的集成业务体系结构,其中的关键是业务互通问题;其中IP用于网络互联,SIP用于建立终端和服务器间的业务会话,提供业务之间的互作用,实现端到端业务能力的集成和最终应用的集成需要新的网格业务技术;下一代网络除要有分别支持网络互联、会话建立和业务集成的能力以外,还必须建立网络、会话和业务之间的新的互作用关系,使得下一代网络的目标得以实现.     

Confirming Connectivity in Interworked Broadcast and Mobile Networks

Industry reactions to major shifts such as mobile broadcast convergence are typically a mixture of opportunities and threats. Both the mobile and the broadcast industries acknowledge the role that convergence will play in their commercial futures, but both would prefer to achieve convergence "on their own patch." For this reason, the most appealing solution to fulfil the contrasting requirements from the different players is represented by interworking between these networks rather than integration. This approach avoids integration, thereby minimizing the changes required in each network and ensuring each network remains an autonomous, independently managed entity. The Internet protocol (IP) is chosen as the "glue" between these heterogeneous networks, providing the generic interworking platform. The main reason behind this choice is that IP was designed as an "interworking protocol" to connect multiple, physically-different networks in such a way as to remain independent of the underlying transport mechanisms used. This article concentrates on the confirm connectivity architecture definition of the interworking model between WLAN, 3G, and DVB. Broadcast networks are uni-directional in nature. When a user wants to receive a service over a broadcast network, there is no way to know whether the broadcast interface of the terminal is configured correctly. In this article we describe a method to automatically configure and test, without user intervention, that the DVB interface of the terminal can receive datagrams from the broadcast network. Furthermore, an optimization method to reduce the total number of confirm connectivity messages (CCMs) sent by the multimode terminals is introduced with simulation results to validate and prove its effectiveness     

Wireless Network Security and Interworking

A variety of wireless technologies have been standardized and commercialized, but no single technology is considered the best because of different coverage and bandwidth limitations. Thus, interworking between heterogeneous wireless networks is extremely important for ubiquitous and high-performance wireless communications. Security in interworking is a major challenge due to the vastly different security architectures used within each network. The goal of this paper is twofold. First, we provide a comprehensive discussion of security problems and current technologies in 3G and WLAN systems. Second, we provide introductory discussions about the security problems in interworking, the state-of-the-art solutions, and open problems.     

Deriving protocol converters for communications gateways

Gateways are introduced for interworking between several, possibly heterogeneous, distributed computer systems. A gateway has to provide for the necessary adaptation between the communication protocols used in the interconnected networks. The adaptation problem is best handled by considering the communication services of the interconnected systems. Once the problem is solved at this level, the remaining problem of conversion between the incompatible communication protocols used in the different systems can be solved automatically, as demonstrated for the case of a simple example of data transmission service from a sender to a receiver process     

媒体网关控制器中H.248与SIP信令互通的研究

H.248和SIP是NGN网络中的两种重要协议,而媒体网关控制器（MGC）则是实现它们互通的重要设备之一。文章在分析了它们互通的必要性的基础上,分别对H.248和SIP协议进行了简单的概述,然后提出MGC的内部结构模型及协议互通的解决方案,最后,通过具体实例来研究它们互通的实现方法。     

Design of the Access Network Segment of Future Mobile Communications Systems

An important component of future mobile communications systems is their access network segment that enables interworking between the mobile unit and the fixed network. In this paper we define and solve two important problems, related to the design of this segment. First, the efficient utilisation of the available radio spectrum. In this context we present a scheme that may be used for reconfiguring the frequency allocation, therefore, improving the spectrum utilisation. The second problem that we address is that of deploying Cell Site Switches (CSSs), and Local Exchanges (LEs). Our aim in this paper is the following. First, to formally define and optimally formulate these problems. Second, to solve them resorting also to computationally efficient heuristic algorithms. Finally, to provide results and draw subsequent conclusions.     

ActiVECOM: An inter-working framework for Corba and DCOM based on a generic protocol

The constant rising of networks and the decrease of computer system costs have enforced the development of distributed platforms. Microsoft dcom (distributed component object model) and omg (object management group) Corba (common object request broker architecture) are two major solutions to develop distributed applications. However, heterogeneity of these platforms is a fundamental problem which prevents applications to inter-work because they depend on their platform support. Then, each of them introduces its own functionality from several perspectives: they define distinct Idls (interface definition language), distinct system mechanisms (for instance, object binding is based either on object references or on interface binding handles) and distinct communication protocols: orpc (object remote procedure call) for dcom and hop (Internet inter-ORB protocol) for Corba. While the commonly used approaches are based on bridges or on parsers, we propose, in this paper, an alternative approach to enable inter-working between Corba and dcom applications. Actually, we present a model called “activecOM” which provides native interworking between Corba and Dcom. In particular, an original solution — called grip for generic remote invocation protocol — obtained by combination of hop and orpc internal protocol behaviours is described. The grip protocol inherits both the robustness of orpc and the simplicity of hop. It also preserves compatibility with those solutions and enables interoperability without the use of bridges.     

Giving Legs to the Legacy — Web Services Integration Within the Enterprise

Behind the hype of Web Services (WS) is the reality of a sound and functional set of technologies for integration. This paper describes how the pragmatic use of WS technology has resulted in better, cheaper and faster integration for BT in its core operational support systems (OSS) system interfaces. BT has embarked upon a programme of enabling key components and middleware layers in its customer handling stack to leverage the benefits of Web Services in addressing the challenge of real-time heterogeneous interworking. It is believed that the WS-enabling of these legacy systems has helped add years to their productive use and protected the huge investment already made in these systems. As well as giving ‘legs’ to such legacy systems, Web Services support the drive to implement a service-oriented architecture inside BT and this paper investigates the ways in which this is being achieved. In order to exploit Web Services on BT's mission-critical platforms we have had to understand and work with WS issues on a wide range of platforms, proving the interoperability, performance and security of the new technologies in large-scale enterprise integration projects. Integration has been the first ‘killer application’ for Web Services and this paper will describe some of the business areas that have benefited from the cleaner integration that Web Services offer. This revised version was published online in July 2006 with corrections to the Cover Date.     

网络简化与多业务交换

PSTN（公用交换电话网）将逐渐向分组化和宽带化的方向演变,在演变过程中,PSTN的网络简化与采用多业务交换平台,将起重要的作用。文中对这两方面作一简要介绍,说明网络简化的目标和应考虑的实际问题,包括远端交换模块和转接局、网关局的合理配置,以及大容量交换系统的选用。并以E-Cube多媒体交换系统为例,说明窄带STM（同步传送模式）和宽带ATM（异步传送模式）的综合交换,窄带业务与IP的结合,以及ATM与IP的结──MPLS（多协议标记交换）。这种多业务交换平台用在ATM／IP骨干网的边缘级,将有利于PSTN与各种新型网络互通。     

Intersegment handover between terrestrial and satellite segments:analysis and performance evaluation through simulation

In future generation communication systems, integration among different segments (terrestrial indoor, terrestrial outdoor and satellite) will be necessary if aiming at providing real global and contiguous coverage without interruption. To achieve integrated or interworking systems efficient algorithms to perform intersegment handover (ISHO) must be implemented. In this way, the switching among different segments can occur without dropping of the call. The paper aims at analyzing some ISHO procedures developed in the frame of some European projects and at evaluating their performance for different system configurations utilizing a dynamic constellation simulator in the time domain. On the basis of the above procedures, aiming at optimizing resources, a new procedure is proposed and analyzed. For each procedure the execution delay and its range of variation have been evaluated for different constellation geometry. Finally, a performance comparison among the various procedures is shown     

20-Gb/s integrated DBR laser-EA modulator by selective area growth for 1.55-/spl mu/m WDM applications

For the first time, selective area growth (SAG) has been used for the monolithic integration of a distributed Bragg reflector (DBR) laser with an electroabsorption (EA) modulator, designed for WDM communication systems at 1.55 /spl mu/m. A 16-GHz bandwidth combined with a 6-nm tuning range make this component compatible with multiwavelength 20-Gb/s transmission experiments.     

WLAN-GPRS integration for next-generation mobile data networks

The ongoing wireless LAN standardization and R&D activities worldwide, which target bit rates higher than 100 Mb/s, combined with the successful deployment of WLANs in numerous hotspots justify the fact that WLAN technology will play a key role in wireless data transmission. Cellular network operators have recognized this fact, and strive to exploit WLAN technology and integrate this technology into their cellular data networks. For this reason, there is currently a strong need for interworking mechanisms between WLANs and cellular data networks. We focus on these interworking mechanisms, which effectively combine WLANs and cellular data networks into integrated wireless data environments capable of ubiquitous data services and very high data rates in hotspot locations. We discuss the general aspects of integrated WLANs and cellular data networks, and we examine the generic interworking architectures that have been proposed in the technical literature. In addition, we review the current standardization activities in the area of WLAN-cellular data network integration. Moreover, we propose and explain two different interworking architectures, which feature different coupling mechanisms. Finally, we compare the proposed interworking architectures, and discuss their advantages and drawbacks.     

号码携带业务对IMS网络互通影响分析

重点讨论了IMS网络在网间互通时的原则,由此引出关口局融合的概念和阶段性建议。特别就号码携带业务对IMS网络互通的影响,结合关口局融合改造的各个阶段提出了具体解决方案。     

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.     

Interworking and interoperability issues for North American PCS

Six air interface standards for personal communications service (PCS) based on two different mobile application parts (MAPs) have been adopted by the TIA TR-46 committee, for PCS to deliver seamless communications, it is important to solve the interworking and interoperability (I&I) issues between similar and dissimilar systems. We examine I&I issues between similar and dissimilar systems. We focus on the I&I issues related to authentication and registration, intersystem startup, intersystem handoff, and privacy, and point out the problems that must be addressed to achieve seamless communications for the PCS environment. The TIA's proposed solution to achieve I&I between the IS-41 and DCS1900 MAPs is also evaluated using a simple traffic model in the metropolitan (urban) environment. The proposed solution puts a significant amount of additional signaling load on the network