基于NGN的矿用综合业务调度通信系统

针对推进我国三网合一以及完善煤矿通信系统的趋势,分析了现代煤矿调度通信系统的业务需求,提出了一种基于下一代网络技术的矿用综合业务调度通信系统,并构建了一个有效的系统模型。基于TDM和IP的多网融合调度平台,采用功能模块化的开发模式,设计并实现了行政电话、调度电话和IP语音接入等语音功能模块,为煤矿井上井下调度通信提供了一种可行方案。     

空管分局级通信网络IP化方案探讨

根据贵州空管分局业务扩展的需求,业务网络的IP化和承载网络的分组化已经成为通信网转型中一个主要的发展方向,通过相关技术体制的介绍,给出了本场和外台的组网方案,组建一套高可靠综合业务承载IP网络,实现雷达、甚高频,电话、监控信号和网络在IP网上传输.     

利用JAIN SCF实现基于位置呼叫转移业务

下一代网络将电信网和IP网融合在一起,可以提供更多新的融合业务,将给业务提供商和网络运营商带来更多的收益。作为这样一种新的增值业务,基于位置的服务有着巨大的潜力。文章集中分析了一种使用JAIN SCF实现基于位置呼叫转移的融合性业务,最后对这个方案进行了评估。     

IP网与传统电信网开放电信业务的比较

目前,通信发展的热点之一是在IP网络上开放电信业务,我国正在IP网络上进行开放电话/真业务的试验。本文从经济和服务质量两方面对在传统电信网上和在IP网上开放电信业务进行了比较,并提出了在IP网络上开放电信业务的看法。     

利用JAIN SCF实现基于位置呼叫转移业务的研究

下一代网络将电信网和IP网融合在一起，可以提供更多新的融合业务，将给业务提供商和网络运营商带来更多的收益。作为这样一种新的增值业务，基于位置的服务有着巨大的潜力。文章集中分析了一种使用JAINSCF实现基于位置呼叫转移的融合性业务，最后对这个方案进行了评估。     

浅析IP电话与移动通信的融合方案

在IP电话和移动通信融合的领域内,对于IP电话系统将手机作被叫提出了3种解决方案,并分析它们的优缺点,确定优选的方案。提出了长途业务分流方案,同时提出了多种分流策略,以使运营商利用IP技术节省运营成本而资费不受影响。为了提高基于IP电话的手机语音质量,提出了GSM直接打包方案。     

基于PTD2112的VoLTE 4G手机研究

LTE模式下主要的语音解决方案有双待机方案、CSFB和VoLTE。基于VoLTE的方案,有功耗低、软件健壮度好、话音数字信号处理方便等方面的优势。提出了一种采用PTD2112的VoLTE 4G手机实现方法,IP电话采用实现简单的SIP协议,核心业务控制网络是IMS（IP多媒体子系统）网络,配合LTE网络实现端到端的基于分组域的语音、视频通信业务。重点阐述基于PTD2112的VoLTE 4G手机的硬件与软件设计方法,该4G手机在中国移动的LTE网络运行良好,能实现电话的主叫和被叫。     

下一代通信网络建设初探

对于基础网络设施匮乏的电信运营商,为了能在当前竞争激烈的通信市场上取得一席之地,必须寻求一种经 济、灵活,能够快速提供各种业务的综合性网络。NGN的实现是基于IP承载网的,业务上要实现和PSTN用 户的互通,因此结合现网的组织结构来考虑NGN的搭建方案是基本出发点。提出了NGN的初期建设方案, 在这样一个统一、开放的系统构架上,支持话音和多媒体等丰富的NGN业务,不仅实现了网络的融合,而且 实现了业务的融合,使得NGN不仅能够继承原有PSTN中所有的业务功能,而且可以在全省范围内快速开展 丰富的NGN新业务。     

IP电话与IP传真业务融合的关键问题

1概述目前在绝大多数情况下,IP电话是不能用于发传真的。也就是说,IP电话与IP传真通常是分离的,用户不能够像使用传统的固定电话那样,在一条电话线上随意地使用语音业务和传真业务。这主要是因为IP电话采用了压缩技术,如G郾729A或G郾723等编码方式,它们主要是针对语音的,而传真与语音具有完全不同的数据特性,这些语音压缩算法并不适用于传真,并且IP电话和IP传真的数据封装格式也不一样。因此,要实现这两种业务的融合,满足用户的需要,必须对IP电话的相关设备尤其是网关采取一些技术措施。本文针对IP电话与IP传真业务融合时面临的主…     

浅析流控传输协议(SCTP)

随着技术的发展,Intemet和电话网PSTN之间的网络融合已经是一种必然的趋势,如何在IP网上实现语音业务,而且同样具有PSTN的业务质量和安全性保证,这就需要能够在IP网上既可以实现数据传输,也可以实现控制信令的传输。SCTP流控协议就是这样一种协议。本文将详细介绍协议的框架,分析协议的功能,分析此协议之所以能成为下一代网络的基本协议的原因。     

True number portability and advanced call screening in a SIP-basedIP telephony system

Custom local area signaling service features offered in the PSTN have certain limitations due to the closed nature of PSTN network signaling. The adoption of telephony over IP (IP telephony) will enable a new paradigm of services and features that are not possible to implement in today's PSTN. This is especially the case for services that make use of personal, trusted information, which can be provided by a user's personal digital assistant. We demonstrate how personal information can be coupled with an IP telephony service to provide user-customized call handling by the network. In particular, we describe a demonstration architecture that includes Ethernet-attached phones running SIP, with an interface to synchronize with PDAs that supply personal information. The proposed architecture is quite flexible; it can support enhanced versions of the current PSTN and private branch exchange services, in addition to many new features and services. We describe true number portability and advanced call screening as examples of new services in a hybrid PSTN/IP telephony environment     

Vulnerability analysis and best practices for adopting IP telephony in critical infrastructure sectors

IP telephony has been rapidly introduced to replace the traditional circuit switched infrastructure for telephony services. This change has had an enormous impact on critical-infrastructure (CI) sectors, which are expected to become increasingly dependent on IP telephony services. Reliable and secure telephony service is a key concern confronting most organizations in the critical-infrastructure sector today. With the proliferation of voice over IP (VoIP) services in these organizations, it is important for them to understand the security vulnerabilities and come up with a set of best practices during the evolution of the IP telephony services. This article outlines the potential security issues faced by CI sectors as they transform their traditional phone systems into VoIP systems. Vulnerability analyses are conducted to understand the impact of VoIP security challenges in the new convergent network paradigm. The most common security measures are analyzed to identify their strengths and limitations in combating these new security challenges. A set of recommendations and best practices are offered to address the key issues of VoIP security as IP telephony is being introduced into critical infrastructure.     

网络融合的趋势分析和展望

下一代网络业务、控制、承载、接入分离的思想为未来网络融合提供了统一的架构。网络融合包括业务融合、核心网络融合、接入网络融合、终端融合、运维融合等多个方面。未来融合网络的发展趋势将是在核心控制层采用IP多媒体子系统(IMS),在核心承载层采用因特网协议/多协议标记交换(IP/MPLS)技术,在业务层采用统一开放的业务提供架构,在接入层支持固定、移动、窄带、宽带等多种接入技术,终端则呈现多模化和智能化的趋势,最终实现一个用户、一个号码、一个终端、一个账单、一个核心网络、随时随地享受的全业务模式。     

SIP security issues: the SIP authentication procedure and its processing load

Session Initiation Protocol (SIP) is currently receiving much attention and seems to be the most promising candidate as a signaling protocol for the current and future IP telephony services, also becoming a real competitor to the plain old telephone service. For the realization of such a scenario, there is an obvious need to provide a certain level of quality and security, comparable to that provided by the traditional telephone systems. While the problem of QoS mostly refers to the network layer, the problem of security is strictly related to the signaling mechanisms and the service provisioning model. For this reason, at present, a very hot topic in the SIP and IP telephony standardization track is security support. In this work, the security model used by SIP is described, and the different open issues are highlighted. We focus, in particular, on the problem of authentication providing a short tutorial on the solution under standardization. The architecture of a possible commercial IP telephony service including user authentication is also described. Finally, we focus on performance issues. By means of a real testbed implementation, we provide an experimental performance analysis of the SIP security mechanisms, based on our open source Java implementation of a SIP proxy server. The performance of the server has been compared with and without security support, under various scenarios.     

新兴电信运营商的战略选择——统一的IP核心网

在无连接的IP网上,基于SIP的VoIP系统用软件交换机提供VoIP业务,既可完成固定电话的交换传输,也可完成移动电话的交换传输,差别仅仅是接入方式不同。它不但可以提供传统电话智能网的全部功能,还可以提供传统电话智能网和互联网特征融合的新功能。对于新兴运营商而言,采用这样的系统不仅可以以价格优势、更重要的是可以以功能的优势与传统电信运营商竞争。     

下一代网络的发展趋势--融合与开放

随着网络技术的发展,多种网络将不断融合(固定网、移动网和IP计算机网),未来的网络将是一个统一、综合的网络,综合了分布式计算和通信技术,能方便地提供不同质量的应用.同时未来的网络是业务驱动的网络,所以业务能力开放性是关键因素.本文介绍了下一代网络融合的背景,探讨了融合的层次及其融合的步骤,阐述了下一代网络能力开放所采用的合适的接口、业务平台、开发和运营方式.     

Voice over Internet protocol and human-assisted e-commerce

By fostering the finalization of open standards and the convergence of voice, video, and data, the Internet protocol provides an ideal driver for the definition of the infrastructure for new multimedia and advanced communications applications. Voice over IP represents not only the chance to achieve cost-effective real-time voice communication over IP-based networks, but also the opportunity to build an integrated and open communications service delivery infrastructure. Developments of Web-based information systems and IP telephony in order to enable future e-commerce applications are summarized     

Internet上承载的业务分析

Ｉｎｔｅｒｎｅｔ的开放性促使Ｉｎｔｅｒｎｅｔ上的业务种类越来越多。目前常见的网上业务有：Ｅ－ｍａｉｌ、ＷＷＷ、ＦＴＰ、Ｔｅｌｎｅｔ、电子商务等,Ｉｎｔｅｒｎｅｔ上还可传送一些实时业务,如：ＩＰ电话／传真、多媒体会议、远程教学和远程医疗等业务。但Ｉｎｔｅｒｎｅｔ的网络安全１、服务质量及拥塞处理等方面的缺陷,使其在提供实时业务方面受到限制,这也是在Ｉｎｔｅｒｎｅｔ上开放业务时应注意的问题之一。     

IP电话的若干网络技术问题

IP电话近年来发展很快。文章讨论了IP电话的若干重要的网络技术问题,如:在接收端对话音分组进行还原时采取的策略;对不同的分组给予不同的服务以及IP电话的应用层协议等。     

移动通信与IP的融合

Ｉｎｔｅｒｎｅｔ产业的热点之一是ＩＰ电话。与传统电话相比,ＩＰ电话具有诸多优点,其中最吸引用户的是资费。我国电话业务因资费过高而导致网络利用率低,移动袖应抓住ＩＰ电话建设的契机,将ＩＰ引入到移动网中,既可节省长途中继,又可以降低花费以吸引用户。