软交换网中的信令网关组网方式

本文首先提出了软交换网中信令网关的应用场合,并对信令网关所用到的各种协议进行了详细的分析和比较,归纳出信令网关各种协议适用的组网模式,最后提供了信令网关在各种应用场景、各种设置方案情况下的协议选择建议.     

H．248／MEGACO协议在NGN中的信令解析

媒体网关控制协议——H．248／MEGACO协议是下一代网络应用中的主流协议,它通过信令实现了媒体网关控制器（MGC）对控制媒体网关（MG）的控制,同时媒体网关也可以向媒体网关控制器发送必要的信令信息,从而实现呼叫流程的建立。文中首先介绍了H．248／MEGACO协议的基本概念,然后通过对简单呼叫建立流程的实现,解析了H．248／MEGACO协议信令在NGN中的内容和作用。     

SCTP协议和H.248协议在软交换技术中的应用

SCTP协议主要完成PSTN信令消息在IP网中的可靠传送;H.248协议是媒体网关控制器(MGC)与媒体网关(MG)之间的接口协议,完成媒体网关控制器(MGC)对媒体网关MG的控制,具有良好的扩展性。文章重点阐述了SCTP协议和H.248协议的基本     

一种支持EM信令的中继网关设计与实现

虽然IP电话网络发展迅速,但在相当长的一段时间里,PSTN与VoIP互为补充又相互竞争的存在着,传统电话交换网与IP网络的融合互通正是网关要解决的问题。针对企业专网通信中的EM信令接入到IP网络的问题,设计实现了支持EM信令的中继网关。进行了EM信令中继网关的功能模块分解,描述了EM信令的呼入流程和呼出流程,突破了EM信令网关设计中协议适配和冗余处理2项关键技术。支持EM信令的中继网关,实现了专网中EM中继到NGN网络的平滑接入,并可以扩充支持多种模拟协议,满足专网的使用要求。     

SUA协议:SCCP用户消息在No.7信令网与IP网间的互通

SIGTRAN是由IETF提出的,在IP网上传输No.7信令的协议栈。SUA是其中为No.7信令系统SCCP层用户消息传递提供适配功能的协议。本文简要介绍了SUA的架构、服务和功能,描述了SUA在信令网关与SCCP的互通流程,并分析和比较了SUA与其他协议。     

H.323-SIP信令网关的实现

H.323和会话初始化协议（SIP）都是基于IP网络的多媒体通信协议,采用实时传送协议（RTP）传送实时的音频视频传输,二者之间可以通过设置信令网关互通,完成信令消息的翻译和转换功能。要实现H.323与SIP网络之间的互通,必须解决地址格式的转换、消息映射和终端能力协商等方面的问题。H.323-SIP信令网关在H.323和SIP互通中占有得要的地位,它能够使位于不同网络的用户直接和对端进行媒体交换,实现点到点、点到多点之间的通信。H.323-SIP信令网关的功能会越来越完善,也会越来越适应用户更加广泛的业务需要。     

软交换系统七号信令设计

基于公共交换电话网络大规模应用七号信令的实际情况,对软交换体系结构、信令网关、初始会话协议(SIP)进行了描述。并针对下一代网络的分层思想、软交换的互联互通结构和呼叫流程,提出了利用软交换交换核心平台和信令网关及SIP相互配合实现七号信令的解决方案。描述了软交换系统的七号信令软件结构、信令网关的软件结构,阐述了相应呼叫流程的实现。     

ISDN语音网关的设计实现

基于Windows 2000平台的ISDN语音网关,采用网关分解的思想设计,即信令与媒体分离的思想,采用ISDN适配卡与CAPI(COMMON-ISDN-API)接口编程技术,使ISDN网络与LAN有效的连接起来,可以使任何一端的语音数据流低延时地传送到另一端.LAN中采用的VoIP技术使用SIP协议,在ISDN信令网关的实现时主要考虑如何将ISDN控制信令协议转化为SIP协议.作为一种结合ISDN和SIP技术的应用,将ISDN的广泛应用性与SIP的流行发展性有效地结合起来,使ISDN语音网关具有成本低廉,简单实用,效果好,低延时等优点,可广泛应用于呼叫转移和呼叫中心,办公信息化等领域.     

新发布的19项通信行业标准

近日,信息产业部以“信部科[2002]269号”文发布了19项通信行业标准,简介如下: 1.YD/T 1191—2002《No.7信令与IP互通适配层技术规范——消息传递部分(MTP)第二级对等适配层(M2PA)》 该标准规定了M2PA提供的业务和功能、M2PA的消息格式、M2PA链路状态和M2PA程序。适用于采用MTP3协议的信令网关与媒体网关控制器之间、信令网关与IP信令点(IPSP)之间或IP信令点(IPSP)和IP信令点(IPSP)之间。     

基于SIP和CMPP的即时消息网关的设计和实现

文章基于SIP和CMPP协议,提出了一个即时消息网关的设计与实现方案,使IP网络上的SIP即时消息可以与CMPP消息互通.在实现了SIP、CMPP协议的基础之上,进一步给出了一个实现短信网关接口的简单模型,并从网关的体系结构、典型信令流程、协议映射方面进行了分析,最后对整个方案进行了总结.     

SCTP数据传输模式在SG中应用研究

信令流控制传送协议(SCTP)是根据RFC 2960(2000)建议制定的。SCTP协议主要用于在IP网中传送PSTN的信令消息。基于SCTP数据传输模式的基本功能,首先对比分析SCTP与TCP的特点和适用范围,对No.7信令与IP网互通的信令网关(SG)设备进行介绍,详细论述了在M2PA方式下SCTP的应用,并展望SCTP的发展前景。     

SCTP: state of the art in research, products, and technical challenges

The stream control transmission protocol (STCP) is being standardized by the IEFT as a reliable transport protocol to transport SS7signaling messages over IP networks. Due to its attractive features such as multistreaming and multihoming, SCTP has received much attention from the network community, in terms of both research and development. This article introduces the main features of SCTP, and discusses the state of the art in SCTP research and development activities. We also provide a survey of the available products that use SCTP. Finally with a view to stimulating further research in this area, the challenges faced by the SCTP research community are identified.     

流控传输协议SCTP的研究

IETF正式把SCTP标准化为RFC2960，作为一种在IP网上传输七号信令消息的新型传输协议，它继承了TCP和UDP的优点，同时增加了一些新特性，特别是多宿和多流，因此吸引了人们的广泛关注。这里首先要介绍了SCTP产生的背景，接着详细介绍了它所具有的一些特性，最后指出它存在的问题和面临的挑战。     

Evaluation of SCTP for space networks

The stream control transmission protocol has recently been standardized as a new transport layer protocol in the IP protocol suite. SCFP is based on the TCP protocol, but incorporates a number of advanced and unique features that are not available in TCP. Although the suitability of TCP over satellite networks has been widely studied, the suitability of SCTP over satellite networks remains to be evaluated. The objective of this article is to investigate the suitability of SCTP for data communications over satellite networks. We focus on the advanced features of SCTP that enhance its performance in satellite networks. Finally, we provide recommendations on the use of SCTP over satellite networks.     

Improving stream control transmission protocol performance over lossy links

The current stream control transmission protocol (SCTP) does not work well over lossy links. To make SCTP congestion control algorithms robust in lossy networks, the paper first introduces a fine-tuned explicit congestion notification (ECN) mechanism for SCTP in such environment, and then discusses the ECN-D SCTP that can differentiate noncongestion losses from congestion losses. We identify the optimal value of the congestion window for an SCTP source in response to ECN messages in order to maximize the throughput and maintain relatively small end-to-end delay. A simple and practical method to achieve the optimal value is developed by carefully choosing the threshold of queues that support ECN. Because the total goodput performance of SCTP associations is not sensitive to window reduction policies when the network load is heavy, and because fine-tuning SCTP or transmission control protocols congestion window in response to congestion indications using complicated methods may not be worth the increase in complexity of the protocol, the simplified method becomes attractive in achieving the optimal congestion window.     

Secure SCTP – A Versatile Secure Transport Protocol

The Stream Control Transmission Protocol (SCTP) is a new general purpose transport protocol defined by the IETF. Originally intended for the transport of voice signaling data (SS7) over IP networks, SCTP together with newly defined extensions is increasingly considered for other application scenarios as well. These require strong security solutions to authenticate the communication partners and protect sensitive data with respect to integrity and confidentiality. Proposals have been issued on how to protect SCTP transport by using standard security protocols such as TLS and IPsec. However, these solutions introduce limitations or inefficiencies und thus may not be able to fully exploit the capabilities of SCTP. Therefore, we propose a security extension to SCTP named Secure SCTP (S-SCTP) to solve these issues in an efficient and user-friendly way.     

SCTP中引入基于排队延迟的拥塞算法

介绍SCTP拥塞控制机制,并在SCTP关联内引入基于排队延迟的FAST拥塞算法.通过比较分析基于排队延迟和基于数据丢失的两种拥塞算法,阐述基于排队延迟拥塞算法更加适合于网络发展的需求,并提出了SCTP中实现FAST拥塞控制机制的初步框架.     

Chunk Checksum of SCTP for Throughput Enhancement

Stream control transmission protocol (SCTP) uses a checksum in the common header for each packet, by which a corrupted SCTP packet will be regarded as a loss. This letter proposes a new "chunk checksum" scheme for SCTP, in which each data chunk contains its own checksum field to determine a corruption of data chunk. Simulation results show that the proposed scheme could improve the throughput of SCTP transmission in the networks with a high bit error rate     

流控制传输协议研究

文章介绍了流控制传输协议(SCTP)的主要特点:支持多穴主机,支持消息的无序递交,提供端到端的可靠性,提供面向消息的传输,提供相对TCP增强的流量控制和拥塞控制,提供更好的安全性和可扩展性;分析了SCTP的主要应用,强调作为一种通用的传输层协议SCTP是今后发展的方向;综合考察了当前SCTP的研究进展,并给出了相关结论,认为SCTP是一种功能强大的传输层协议.     

SCTP在无线网络上的最佳协议参数配置分析

本文研究了在WLAN、GPRS、UMTS这3种无线网络上运行流控制传输协议(SCTP)时,不同的协议参数配置对系统传输性能的影响。文中找出了达到最大系统传输性能时的SCTP协议参数设置,从而解决了符合IETF-RFC2960的SCTP应用于无线网络上协议最佳参数选择的关键问题。理论分析和仿真结果表明,运行于无线网络上时,采用了最佳参数配置的SCTP协议传输性能明显地高于采用传统参数配置的SCTP协议。