利用ADSL接入网开展VOD业务

本文介绍了视频点播 (VOD)业务 ,并重点阐述了利用不对称数字用户环路 (ADSL)作为用户接入网 ,在现有的双绞电话线上开展交互式通信———VOD业务的网络结构。     

广西移动智能网业务发展分析

从广西智能网业务的市场需求和存在问题入手，介绍了广西智能网业务的定位，并对现有业务在智能网上与BOSS上开展进行了比较。     

业务应用--3G成功的决定因素

欧、亚、美等通信发达地区已经开始发展3G商用网络。目前用户享受到的3G网络包括简单话音／消息、多蝶体信息、定位、移动互联网、高级话音等业务。用户关心的热点业务包括多媒体短信、定位、可视电话、移动电子商务、移动游戏等业务。内容更丰富、服务更贴近生活、地域服务差异性成为3G业务的发展方向，     

Quality of Service Schemes for IEEE 802.11 Wireless LANs – An Evaluation

This paper evaluates four mechanisms for providing service differentiation in IEEE 802.11 wireless LANs. The evaluated schemes are the Point Coordinator Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordinator Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11, Distributed Fair Scheduling (DFS), and Blackburst. The evaluation was done using the ns-2 simulator. Furthermore, the impact of some parameter settings on performance has also been investigated. The metrics used in the evaluation are throughput, medium utilization, collision rate, average access delay, and delay distribution for a variable load of real time and background traffic. The simulations show that the best performance is achieved by Blackburst. PCF and EDCF are also able to provide pretty good service differentiation. DFS can give a relative differentiation and consequently avoids starvation of low priority traffic.     

大中型移动城域综合传送网建设思路探讨

结合目前城域综合传送网的建设情况，从网络结构体系的不同层面对目前移动运营商在此类工程中宜采取的建设方案作一简要探讨；在方案论述中针对各传输层面技术要点进行分析，尤其对骨干传输层的建设方案进行经济性、适用性、可扩展性的比较，总结出适合目前大中城市移动城域传送网建设的相关思路。     

Design and demonstration of policy-based management in a multi-hop ad hoc network

In this paper, we propose a policy-based framework for the management of wireless ad hoc networks and briefly describe a characteristics-based taxonomy that provides a platform to analyze and compare different architectural choices. We develop a solution suite that helps achieve our goal of a self-organizing, robust and efficient management system. One of the main contributions of this work is the prototype implementation and testing of the mechanisms and protocols comprising our framework in a multi-hop ad hoc network environment. Experiments are conducted using both an emulated ad hoc network testbed and a true wireless testbed. Degradation in management system performance is observed as the number of hops between a policy server and client increases. Our proposed k-hop clustering algorithm alleviates this problem by limiting the number of hops between a server and client. We demonstrate the operation of our prototype implementation, illustrating QoS management in a multi-domain ad hoc network environment using the proposed cluster management, redirection, and policy negotiation mechanisms.     

A framework for delivering fine granularity and fair service discrimination in DiffServ networks

In order to achieve a quality of service (QoS) capable of satisfying an ever increasing range of user requirements, differentiated services (DiffServ) have been introduced as a scalable solution that emerges ‘naturally’ from today's best effort service approach. Mapping the packet treatment into a small number of per hop behaviours (PHBs) is the key idea behind the scalability of DiffServ but this comes at the cost of loosing some behavioural differentiation and some fairness between flows multiplexed into the same aggregated traffic. The paper proposes a novel simple and effective DiffServ approach, the ‘Simple Weighted Integration of diFferentiated Traffic’ (SWIFT), and uses it in a series of simulations covering a relatively wide range of local network conditions. Measured voice and video traffic traces and computer generated self‐similar background traffic were used in simulations performed at various congestion levels and for in‐profile and out‐of‐profile source behaviour. The resulted throughput, mean delay, maximum delay and jitter are used to asses SWIFT's capabilities—isolation of the in‐profile traffic from congestion effects, treatment differentiation, increased resource utilization, fairness in treatment under congestion, and incentivity for nice behaviour. Comparisons with other approaches employing traffic control are also provided. Copyright © 2003 John Wiley & Sons, Ltd.     

北京本地智能网的应用与发展

本文从北京智能网的网络结构、业务应用两个方面论述了北京本地智能网的应用，并对北京智能网今后的发展提出了作者的见解。     

移动生活方式

移动市场上主要有3类移动门户:移动运营商、Web门户和移动门户的新进入者。无线应用业务提供商(WASP)是移动门户市场领域正在成长的一员,WASP与移动运营商合作将可以帮助运营商门户对客户市场进行细分。移动门户要想获得成功需要制定泛欧或全球战略、寻求合作、依托运营网络的品牌、提供个性化内容和服务以及提供多种接入。移动门户应采取开放式门户的模式,这样可以为其它网络的客户提供接入的机会。     

Analysis of a queueing system with a general service scheduling function,with applications to telecommunication network traffic control

In this paper we analyze a queueing system with a general service scheduling function. There are two types of customer with different service requirements. The service order for customers of each type is determined by the service scheduling function α_k(i, j) where α_k(i, j) is the probability for type-k customer to be selected when there are i type-1 and j type-2 customers. This model is motivated by traffic control to support traffic streams with different traffic characteristics in telecommunication networks (in particular, ATM networks). By using the embedded Markov chain and supplementary variable methods, we obtain the queue-length distribution as well as the loss probability and the mean waiting time for each type of customer. We also apply our model to traffic control to support diverse traffics in telecommunication networks. Finally, the performance measures of the existing diverse scheduling policies are compared. We expect to help the system designers select appropriate scheduling policy for their systems.