IMS与3G电路交换(CS)域的互通研究

从R5版本后,3G核心网分成了CS(电路交换)域、PS(分组交换)域和IMS(IP多媒体子系统),因此IMS需要与CS域以及PSTN等传统网络进行互通,以实现各种业务。本文介绍了IMS的体系结构,分析了IMS与CS域的互通结构以及相应的互通网元。并通过具体的会话建立和会话释放信令流程,重点探讨了IMS与CS域互通的实现过程。     

电路交换域与IMS互通研究

IMS是3GPP组织在R5版本上提出的支持IP多媒体业务的子系统,它最显著的特点是采用了SIP协议。现在,UMTS系统中包含三个域:电路交换域,分组交换域和IMS。IMS必须和传统的电路交换用户如PSTN用户进行交互,这篇文章对电路交换域和IMS的互通作了探讨。文章首先简要介绍了IMS中用于互通的网络实体及其功能,然后分别从控制平面和用户平面描述了IMS用户和电路交换域用户的互通,最后给出了控制平面上的SIP协议和ISUP协议的映射。     

IBM IP多媒体子系统(IMS)解决方案--提供推动提升业务收入和降低成本的下一代电信多媒体服务

在经历一个多世纪的专用网络和垄断后,过去10年来电信行业的重大技术发展(不管是技术推动还是来自政府监管要求的推动)正在将占据主导地位的话音网络向多业务分组网络演进.互联网协议(IP)的优点和光明前景正被延伸到传统的公用交换电话网络(PSTN)及公用陆地移动网络(PLMN)中,而且有望构建一种基于分组技术的新型网络.这种网络是一种更简单、无处不在而且更为灵活、"便宜"的全球多业务网络.这种新的分组交换网络经常被称作下一代网络(NGN).它采用互联网模式,其中话音通信只是网络中的(实时)应用之一.3GPP UMTS第5版中推出的IMS(IP多媒体子系统)使电信公司可以使用分组交换技术来完成话音业务传输,利用会话控制实现数据和多媒体业务.因此,IMS可以认为是移动网络的NGN标准.     

电信运营商网络融合的思考

电信运营商在其全业务运营时如何进行网络和业务的融合已成为重要课题.简要介绍了下一代网络的分层结构,对核心网的两种架构--软交换和IMS(IP多媒体子系统)进行了讨论和比较,并对电信网络由PSTN(公用交换电话网)逐步演进到IMS的进程进行了思考和探讨.     

IMS网络话务路由优化方案

我国部分地区IMS(IP多媒体子系统)用户与PSTN(公共交换电话网络)用户的呼叫一般采用固定软交换系统转接,IMS与PSTN互通的话务路由严重迂回,随着IMS用户量不断增加,对区内话务汇接路由进行优化已迫在眉睫。文章首先对IMS的结构和实体进行简单介绍,然后结合实际对区内电信网络现有的路由进行优化和测试,最终达到优化话务路由的目的。     

PES体系架构实现方案的比较分析

公共交换电话网/综合业务数字网(PSTN/ISDN)仿真子系统作为下一代网络(NGN)多个业务控制子系统之一,其实现架构主要有两种方式:基于呼叫服务器的方式和基于IP多媒体子系统(IMS)的方式.两种方式各有优劣.文章对这两种方式作了简要介绍,并从核心架构、业务实现方式和演进方式等方面进行了比较分析,最后结合国内电信网络的发展和现状对方案的选择提出了建议.     

固网软交换向IMS演进方案

固网软交换向IP多媒体子系统(IMS)演进应采用合理的方法、步骤和策略。演进可以在继承原软交换(SS)公共交换电话网络业务仿真子系统(PES)业务功能的前提下,平滑地向IMS演进,逐步引入、扩展多媒体和移动业务,实现核心网层面的固定和移动融合(FMC)。下一代网络(NGN)核心控制层的软交换和IMS在基本架构上没有实质冲突,软交换主要面向公共交换电话网(PSTN)仿真业务,而IMS为实现FMC和多媒体业务,在移动性、安全、服务质量(QoS)、开放业务架构等方面作了有益的扩展,软交换向IMS演进在技术上是完全可行的。对于已经采用软交换的运营商,采用演进的方式实现基于IMS的全业务的NGN网络,可以节约投资,减小网络改造风险,降低运营成本。     

NGN、软交换和IMS的关系

下一代网络(NGN)是业界的热点话题,其中关于IP多媒体子系统(IMS)、软交换(Softswitch)的定位和未来发展方向需要达成共识。软交换和IMS都是属于NGN的业务网。软交换从设备的实现而言,应该可以平滑演进到IMS,但是从网络的演进而言,由于软交换将主要支持传统的公共交换电话网/综合业务数字网(PSTN/ISDN)业务,而它的基本业务和补充业务都是在本地实现,因此要实现向IMS的平滑演进有一定难度。     

朗讯科技为KPN提供IMS解决方案

朗讯科技宣布与荷兰最大的电信服务提供商KPN签订了一份合同，为KPN全面部署IP多媒体子系统（IMS）解决方案，以取代KPN原有的公共电话交换网络（PSTN）。作为合同的一部分，朗讯科技全球销售与服务部还将为KPN提供包括网络设计、系统集成、部署、维修和支持服务在内的网络转型服务。另外，朗讯将KPN现有业务和客户无缝转移到其新建的全IP网络中，以满足KPN的市场目标。     

IMS的初始过滤规则及业务提供过程分析

IMS（IP Multimedia Subsystem）是第三代合作伙伴计划（3GPP）在Release 5版本提出的支持IP多媒体业务的子系统。它基于UMTS核心网分组域（PS域），利用PS域来传输呼叫控制信令和承载数据业务，独立于电路域（CS域），但保持与CS域的互通。     

Supporting real-time IP multimedia services in UMTS

UMTS, the successor of GSM, is evolving toward a future wireless all-IP network. We explain how it will support real-time IP multimedia services, as these services are expected to drive the adoption of wireless all-IP networks. We not only focus on the centerpiece of IP multimedia support, the IP multimedia subsystem, but also include the GPRS transport capabilities and OSA middleware capabilities. This helps to explain how the IMS fits in with, and builds upon, other pieces of the UMTS network. We analyze the pros and cons of providing IP multimedia session control capabilities as opposed to just providing basic IP connectivity, and highlight selected features of the IMS design for discussion.     

Multi-domain architecture for policy management inumts ip multimedia subsystem

The Universal Mobile Telecommunications System (UMTS) offers IP-based multimedia applications and services with end-to-end Quality of Service (QoS) guarantee. The key component providing these services is the IP Multimedia Subsystem (IMS) that uses Service-Based Local Policy (SBLP) management for QoS control. To support end-to-end QoS, the UMTS IMS network should be scalable, reliable and flexible in policy deployment and enforcement, characteristics that are not found in single-domain policy architecture. A hybrid policy architecture is proposed, in which a hierarchical architecture is applied to the multi-domain environment in a single operator UMTS IMS network, while a peering architecture is employed in a multi-operator UMTS IMS network. The proposed multi-domain policy architecture potentially minimizes the session setup delay and policy exchange traffic while maximizing network scalability.     

SIP在3G网络中的应用

第三代移动通信系统是能提供多种类型IP数据业务的通信系统.会话起始协议SIP是3G的IP多媒体子系统中提供多媒体业务的核心技术.文章首先介绍了SIP的基本工作原理,然后对3GPP UMTS R5定义的IMS进行了简要描述,最后详细阐述了SIP在IMS提供服务的过程及对漫游用户的处理.     

One-pass GPRS and IMS authentication procedure for UMTS

Universal Mobile Telecommunications System (UMTS) supports Internet protocol (IP) multimedia services through IP multimedia core network subsystem (IMS). Since the IMS information is delivered through the general packet radio service (GPRS) transport network, a UMTS mobile station (MS) must activate GPRS packet data protocol (PDP) context before it can register to the IMS network. In the Third-Generation Partnership Project (3GPP) specifications, authentication is performed at both the GPRS and the IMS networks before an MS can access the IMS services. We observe that many steps in this 3GPP "two-pass" authentication procedure are identical. Based on our observation, this paper proposes an one-pass authentication procedure that only needs to perform GPRS authentication. At the IMS level, authentication is implicitly performed in IMS registration. Our approach may save up to 50% of the IMS registration/authentication traffic, as compared with the 3GPP two-pass procedure. We formally prove that the one-pass procedure correctly authenticate the IMS users.     

Security and Authentication in the Mobile World

Mobile systems are evolving into data centric, packet switched,multiacess networks. New types of security threats are emerging in thesenew networks. From the user point of view a seamless solution for thesethreats is required. This paper presents a vision of network convergenceand its implications to authentication and authorization solutions.Security requirements are discussed and current authentication solutionsin GSM, UMTS and operator wireless local area networks (OWLAN) areintroduced. All-IP multimedia session security is discussed.Implications of AdHoc network architecture into security requirement arediscussed.     

浅谈IP多媒体子系统业务平台

文章研究了3GPP在UMTSRel5、Rel6演进版本中提出的IP多媒体子系统(IMS),描述了IMS在基于分组域上提供电话和非电话业务的系统架构。IMS的提出对固网和移动网络的融合起到了很大的推动作用,研究基于IMS的统一业务平台对下一代业务平台体系架构具有一定参考意义。     

SIP Multicast-Based Mobile Quality-of-Service Support over Heterogeneous IP Multimedia Subsystems

The Universal Mobile Telecommunications System (UMTS) all-IP network supports IP multimedia services through the IP Multimedia Subsystem (IMS). This paper proposes a mobile Quality-of-Service (QoS) framework for heterogeneous IMS interworking. To reduce the handoff disruption time, this framework supports the IMS mobility based on the concept of Session Initiation Protocol (SIP) multicast. In our approach, the mobility of a User Equipment (UE) is modeled as a transition in the multicast group membership. With the concept of dynamic shifting of the multicast group's members, the flow of actual data packets can be switched to the new route as quickly as possible. To overcome mobility impact on service guarantees, UEs need to make QoS resource reservations in advance at neighboring IMS networks, where they may visit during the lifetime of the ongoing sessions. These locations become the leaves of the multicast tree in our approach. To obtain more efficient use of the scarce wireless bandwidth, our approach allows UEs to temporarily exploit the inactive bandwidths reserved by other UEs in the current IMS/access network. Analytic and simulation models are developed to investigate our resource reservation scheme. The results indicate that our scheme yields comparable performance to that of the previously proposed channel assignment schemes.     

3G UMTS中的IP多媒体子系统探析

下一代的移动通信系统将基于全IP的网络构架,提供开放的业务生成环境。3GPP在其UMTSR5版本中首次引入了IP多媒体子系统(IMS)的概念,作为下一代网络的重要平台,IMS不仅实现了固网与移动网业务的无缝融合,还有利于运营商快速、灵活地开发更加丰富多彩的移动多媒体业务,从而吸引大量的终端用户。文章在描述IMS体系结构的基础上,特别针对IMS中几个关键要素点进行了重点分析。     

IMS关键技术及业务应用研究

3GPP UMTS体系标准的R5版本中引入的IMS是为支持移动多媒体业务而设计,是第三代移动通信核心网络的重要组成部分。论文首先对IMS的关键技术做了归纳总结,然后重点介绍了IMS的安全功能。在此基础上讨论了IMS中的业务架构和基本业务。