基于ZXSS10 SS1b软交换的SIP终端会话设计

软交换技术是现代交换技术中一个重要的分支,其开放的体系结构支持多种信令协议,而SIP协议是其中重要协议之一,主要用于实现实时会话通信。通过对软交换体系结构的介绍以及软交换中SIP协议的应用分析,利用中兴公司的ZXSS10 SS1b软交换控制设备实现了在实验室条件下的SIP终端会话设计,给出了具体的设计过程及实验结果,为高校通信与电子信息类专业建设现代通信实验室、开设相关实验提供了有效方案。     

Network‐initiated simultaneous mobility in voice over 3GPP‐WLAN

VoIP over WLAN (VoWLAN) gradually has become a popular application with the fast maturing of both WLAN and Voice over IP (VoIP) technology. However there exists one problem that heavily affects the satisfaction of the users which is that the mobility of the mobile host (MH) can disrupt or even intermittently disconnect an ongoing real‐time session. Therefore the issue of how to reduce the handover delay gets more and more important. This paper proposes a Network‐Initiated SimUltaneouS mobility (NISUS) mechanism to facilitate terminal mobility with the session initiation protocol (SIP) in Voice over 3GPP‐WLAN. We design the E2E tunnel state model running on the packet data gateway (PDG) referring to the CAMEL concept. The NISUS is triggered at the PDG by detecting the state transition of the E2E tunnel state model that represents the occurrence of a handover. Then the PDG sends the handover request to notify the Mobility Server (MS) to perform a third party call control (3PCC) and a third party registration on behalf of the MH in parallel for session re‐establishment. With the help of the MS we ensure the lost signaling messages could be correctly re‐sent to moving hosts. Moreover the Master‐Slave Determination procedures derived from H.245 are proposed for the MS in order to handle the racing conditions fairly when two MSs involved in a simultaneous mobility issue 3PCC calls respectively at about the same time. We demonstrate the NISUS works well in the simultaneous and non‐simultaneous movement cases. Analytical results show that the handover delay can be improved significantly by using the NISUS compared with the mobile‐initiated simultaneous/non‐simultaneous mobility. Copyright © 2010 John Wiley & Sons, Ltd.     

会话边缘控制器关键技术实现

通过对会话边缘控制器(SBC)及相关的SIP协议、网络地址转换/防火墙、媒体处理、拓扑隐藏及协议修改技术的说明,给出了SBC的核心模块的设计原型,并对信令代理和媒体代理关键子模块进行了设计实现说明。采用B2 BUA、状态机、SIP/RTP/RTCP消息修改、地址映射、回调函数、媒体流处理、服务质量(QoS)控制策略等技术,对系统做了具体实现。测试结果表明,系统具备了作为一个SBC的功能。     

SIP应用于无线链路的时延分析

本文主要研究SIP协议的会话建立时延,在建模分析无线衰落信道的基础上,讨论SIP消息采用不同的传输层协议获得的不同时延,得出UDP协议比TCP具有较小时延的特点。     

Analysis and Applications of Session Initiation Protocol (SIP) in Internet Telephony

1　Introduction　Internet telephony, also known as Voice over IP (VoIP)or IP telephony (IPtel), is the real time delivery of voice(and possibly other multimedia data types) between two ormore parties, across networks using the Internet protocols,and the exchange of information required to control this de livery. Internet telephony offers the opportunity to design aglobal multimedia communications system that may eventual ly replace the existing telephony infrastructure.　Internet Engine…     

TLS会话复用的客户端安全分析与改进措施

为了减少不对称计算带来的性能降低和资源消耗,在传输层安全性协议(TLS)中设计了会话复用机制.该机制使TLS1.2握手过程降为1个往返时延(RTT),并且使TLS1.3实现了0-RTT.基于此,通过研究会话标识(session id)、会话票据(session ticket)和预共享密钥(PSK)3种实现方式,并分析了...     

A call‐state‐based service triggering algorithm for IMS network

To determine the potential signaling traffic reductions, the session establishment procedures were investigated. The investigation showed that the serving call session control function (S‐CSCF) is the major bottleneck in IP multimedia subsystem (IMS) network and the existing third‐generation partnership project (3GPP) service triggering algorithm (3GPP STA) based on initial filter criteria (iFC) increases largely the end‐to‐end session setup delay (SSD). To reduce the SSD and improve the system performance, a call‐state‐based application triggering architecture (CATA) was proposed. In CATA, the call‐state‐based filter criteria and the call‐state‐based service triggering algorithm (CSTA) were proposed, and then the modeling of 3GPP STA and CSTA was presented. Theoretical analysis and simulation results showed that the CSTA avoids the additional signaling traffic load of the S‐CSCF and application server effectively, which exists in 3GPP STA, reduces the SSD considerably, increases the throughput of the S‐CSCF and improves the quality of service of IMS network. Copyright © 2008 John Wiley & Sons, Ltd.     

IMS中SIP会话建立时延的改进机制研究

为了减小会话建立时间，IMS中有必要对SIP消息进行压缩。文章首先给出了一种SIP会话建立时延模型，接着分析了各种与时延相关的因素并提出了改进SIP会话建立时延的方法，最后从SIP压缩角度提出了一种改进SIP会话建立时延的改进机制。     

Efficient and flexible password authenticated key agreement for Voice over Internet Protocol Session Initiation Protocol using smart card

Providing a suitable key agreement protocol for session initiation protocol is crucial to protecting the communication among the users over the open channel. This paper presents an efficient and flexible password authenticated key agreement protocol for session initiation protocol associated with Voice over Internet Protocol. The proposed protocol has many unique properties, such as session key agreement, mutual authentication, password updating function and the server not needing to maintain a password or verification table, and so on. In addition, our protocol is secure against the replay attack, the impersonation attack, the stolen‐verifier attack, the man‐in‐the‐middle attack, the Denning–Sacco attack, and the offline dictionary attack with or without the smart card. Copyright © 2013 John Wiley & Sons, Ltd.     

基于DFA的HTTP会话学习模型

由于Web应用涉及范围广,结构复杂多变等特点,对其采用的入侵检测面临着严峻的考验。具有学习功能的入侵检测有着广阔的研究前景。提出一种异常检测方法,从HTTP连接中提取HTTP会话,按照RFC标准描述HTTP请求,以此构建基于DFA的HTTP会话学习模型。并针对HTTP请求数量庞大的特点,提出模型简化的算法。该模型能够实现自动更新,有助于解决入侵检测保护Web应用时遇到的问题。     

A Session Layer Concept for Overlay Networks

Current day mobility solutions are characterized by a number of essential restrictions that prevent them from being successful in an overlay network environment. This paper proposes 4 properties that mobility solutions must have to address these restrictions: application cooperation, higher layer mobility awareness, general applicability and protocol heterogeneity. Subsequently, a mobility solution that realizes all these properties is described. The solution introduces a session layer in the protocol stack that consists of two subsystems: the connection abstraction system and the address management system. Other mobility solutions found in the literature, session layer and others, typically only realize a subset of the four properties. Tom Mahieu holds a Bachelor's and Master's degree in computer sciences that he obtained at the Catholic University of Leuven. After obtaining his Master's degree in 1997, he was admitted into the Distrinet research group at the Department of Computer Science of the Catholic University of Leuven in Belgium as a research and teaching assistant, where he is current working on flexible component architectures for protocol stacks under the supervision of Prof. Pierre Verbaeten and Prof. Wouter Joosen. His Ph.D. dissertation deals with protocol stack support for applications that operate in dynamically changing network environments, such as mobile and wireless networks. Pierre Verbaeten is the head of the DistriNet research group. His main research interest is on system support and software engineering support for distributed systems. Under his supervision, DistriNet has grown to a group of 40 researchers (both Ph.D. students and postdocs) and 6 professors. He is responsible for teaching courses on computer architecture, computer networks and distributed systems. Wouter Joosen received a Ph.D. degree at the K.U. Leuven in 1996. His main research interests are in the areas of software architecture for distributed systems, aspect-oriented and component-based development, middleware, software security and embedded systems. Over the last 10 years, Wouter Joosen has been researching software development technologies (processes, architectures, notations and prototypes) that enable the construction and management of distributed applications that need support for a number of non-functional requirements, including security, real-time aspects, reliability and load balancing.     

Session Facade在分布式系统中的应用研究

讨论一种J2EE设计模式Session Facade在分布式系统开发设计中的使用,进一步针对分布式系统并行处理的复杂性,结合Singleton模式提出对Session Facade的一种改进方法。通过设计模式的改进可以显著提高某一个领域内系统开发设计的效率,能够有效增强系统的安全性、数据完整性、性能、可维护性和可扩展性。     

Simultaneous mobility: analytical framework,theorems and solutions

The original Mobile IP (MIP) protocol does not perform Route Optimisation but uses Home Agents to forward traffic. Thus, it does not have problems with simultaneous mobility, that is, the special case when both end hosts are mobile and move at about the same time. However, MIP for IPv6 (MIPv6) uses binding updates that are sent directly to a correspondent node. Session Initiation Protocol based mobility management (SIPMM) and MIP with location registers (MIP‐LR) also use direct binding updates between a mobile host and a correspondent node. Thus, MIPv6, MIP‐LR and SIPMM are vulnerable to the simultaneous mobility problem. In this paper, we analyse the simultaneous mobility problem and solution mechanisms, and propose new ways for MIPv6, MIP‐LR and SIPMM to handle simultaneous mobility. Copyright © 2006 John Wiley & Sons, Ltd.     

分布式系统中会话密钥的管理与分配

为解决数据库中敏感信息不被非授权用户的窃取和篡改，提出了通过外购数据库服务（DAS）解决方案。即数据库的拥有者把敏感信息在可信的客户端进行加密，然后把加密的数据库存放在不被自己所控制的服务器上．文中主要介绍在基于角色的密钥管理（RBEM）分布式系统中，关于动态分层中会话密钥的产生和管理方法，以及会话密钥产生的算法。     

基于服务器端会话追踪的Web查询服务的研究

在探讨了Web查询服务的典型模型后,论文阐述了服务器端会话追踪机制的实现方式,设计了基于服务器端会话追踪的Web查询服务的典型解决方案。该设计方案可以较为安全地保存和维护客户的上下文信息,可靠地跟踪用户查询所处的状态,有效地实现有状态的Web查询服务。     

TCP移动性支持方案的研究

传输控制协议(TCP)是在有线环境下设计并调整改善的传输层协议。但是在移动环境中他的端到端性能有所下降，近年来，人们提出了许多新的方案用来提高移动环境下TCP的性能。本文介绍并研究了这些方案，考察了他们的优缺点，并提出了一种新的解决方案。     

一种SIP协议栈中呼叫过程的设计与实现

随着VoIP技术的飞速发展,SIP协议正日益受到业界的重视,越来越多地应用于3G网络。本文提出并基于C语言编程实现一种完全自主设计的SIP协议栈,包括消息编解码模块、状态机模块、传输层模块。实现用户代理客户端和用户代理服务器间的工作状态调度,进而使得两个用户代理能够进行多媒体会话。     

TCP移动性应用层支持方案的研究

如何在无线通信系统中提供高效的移动连接,让移动节点能够随时、随地保持业务的连续性是当前研究的热点。IETF提出的SIP协议以其灵活、容易部署等特性较好地解决了移动节点的全局移动性问题。然而,在利用SIP实现移动TCP应用过程中,频繁的切换过程将会导致TCP连接中断的发生,从而使得各种会话过程和预定业务不能正常进行。就此问题提出了一种基于SIP　EYEagent与SIPINFOmethod实现TCP应用移动性的解决方案。     

基于北京大学无线网的VoIP实现

VoIP利用IP网络实现语音通信,是当前校园网流行的一种网络应用.北京大学利用现有的校园无线网络Wireless PKU实验运行VoIP,实现了用户间利用WiFi手机的SIP语音通信;同时通过与基础电信运营商合作,建立与传统电话业务网的连接,实现真正意义上的IP电话.     

游戏大数据平台工作流引擎研究与实践

随着业务人员对数据分析的需求不断增加,基于开源Hadoop的游戏大数据平台运行着越来越多相互依赖的作业任务.为了更加高效地完成作业管理和调度,升级了Zeus构建工作流引擎,优化Zeus任务启动过程,实现了多线程启动任务,缩短了启动时间.通过扩展Zeus系统,使其支持Oracle存储过程.同时,利用管道技术,实现了异构数据源的无缝高效共享和传输.