ATU UNI信令的功能划分

ＡＴＭ用户－网络接口（ＵＮＩ）信令采用ＯＳＩ的分层结构，本文首先简要介绍了ＡＴＭ ＵＮＩ信令协议的体系结构以及各层的功能。然后详细描述了ＵＮＩ信令功能模块的划分，以及各模块的功能。     

ATM论坛UNI4.0与ITU—T Q.2971

就ＡＴＭ论坛ＵＮＩ４．０与ＩＴＵ－Ｔ Ｑ．２９７１二者在点到多点信令的实现方面作了对比，分析其相同点及不同点，并着重讨论了ＵＮＩ４．０的ＬＩＪ信令方式，提出了具体的实现策略。     

便携式ATM协议分析仪

Ｒａｄｃｏｍ公司的ＡＴＭａｘ－２００是第一部便携式协议分析仪，可解决公司网络管理人员所面临的各种问题，确保ＡＴＭ交换机和适配器具有与交换虚拟电路（ＳＶＣ）兼容的信令模式。ＡＴＭａｘ－２００具有成套软件，可用来测试ＡＴＭ设备处理ＡＴＭ用户网络接口（ＵＮＩ），即建立和折除ＡＴＭ连接的信令协议的能力。ＵＮＩ是ＡＴＭ论坛的一项规范，对利用ＡＴＭＳＶＣ是极其重要的。凭借Ｒａｄｃｏｍ分析仪，网络管理人员可以模拟ＡＴＭ环境，以测试ＵＮＩ互用性装置和检验产品性能。该分析仪具有多端”口接口卡，这意味着，它能同时产…     

ATM网络安全

本文根据ＡＴＭ论坛有关ＡＴＭ安全的相关标准,分析了ＡＴＭ网络中安全性需求及安全机制实现的有关问题。针对ＡＴＭ ＵＮＩ和ＮＮＩ信令的特点。研究安全协议和加密算法的选择及实现的有关问题,并对ＡＴＭ网络安全标准化中存在问题及进上步的研究方向做了一简短的讨论。     

ATM UNI临时本地管理接口

ＩＬＭＩ是ＡＴＭ论坛标准ＵＮＩ的一部分，ＩＬＭＩ规定了ＵＮＩ两边的ＡＴＭ设备如何通过ＵＮＩ交换有关状态和配置的信息。本文介绍ＩＬＭＩ标准的主要内容，包括通信协议和ＵＮＩＭＩＢ，以及同ＮＭＳ和其他ＭＩＢ的关系。     

ATM用户接入设备内部通信机制的实现

ＡＴＭ用户接入设备是一种将多种业务终端（Ｂ－ＩＳＤＮ非标准业务终端）接入ＡＴＭ骨干网的设备。它集宽带终端适配器（Ｂ－ＴＡ）和宽带网络设备（Ｂ－ＮＴ）功能为一体,为实现将现有业务（如电话、会议电视、计算机和低速多媒体等）接入ＡＴＭ网络,并充分利用Ｂ－ＩＳＤＮ的优点提供了可能。ＡＴＭ用户接入设备功能包括：（１）恒定比特率业务（同步业务）和数据业务（异步业务）的适配功能;（２）ＡＴＭ复接／分接功能;（３）提供多个基于ＳＤＨ（ＳＴＭ－１）的１５５Ｍｂ／ｓ物理接口;（４）信令功能（ＵＮＩ信令,支持点对点和…     

宽带ISDN与ATM交换技术──第二讲B－ISDN用户─网络接口和协议（上）

本文介绍了Ａ－ＩＳＤＮ的协议参考模型，并讨论了其中物理层、ＡＴＭ层、ＡＴＭ适配层以及高层的基本功能。给出了Ｂ－ＩＳＤＮ用户─网络接口（ＵＮＩ）的基本规范，包括ＵＮＩ参考配置、Ｂ－ＩＳＤＮ物理层接口以及ＡＴＭ层的参数规定。最后详细描述了ＡＴＭ适配层的协议，包括ＡＡＬ１、ＡＡＬ３／４和ＡＡＬ５。     

ATM交换虚电路信令

ＡＴＭ可以提供两种类型的连接；永久虚电路（ＰＶＣ）和交换虚电路（ＳＶＣ），后者与前者相比具有很多优点。但ＳＶＣ是否能被用户所接受，在很大程度上取决于其信令是否高效、灵活、可靠。本文首先介绍了用户网络接口（ＵＮＩ）上建立到点ＳＶＣ的信令Ｑ．２９３１及建立点到多点ＳＶＣ的令领协议Ｑ．２９７１。然后指出了现阶段ＳＶＣ信令的局限性。     

ATM网络系统

本文首先介绍了异步转移模式概况，接着讨论了ＡＴＭ服务信息的分类，用户网接口通信协议并给出ＵＮＩ物理分层模型，其中着重讨论了ＡＴＭ网络系统的特性。     

元信令规程在ATM网络中的特殊作用

文章介绍了ＡＴＭ网络信令系统中的元信令,分析了元信令在ＡＴＭ中的作用及元信令规程与ＮＩＳＤＮ信令规程的对应关系,并将元信令的功能作了总结。     

利用软件工程的方法开发B－ISDN的用户／网络信令

Ｂ－ＩＳＤＮ的用户／网络信令是ＡＴＭ（异步转移模式）交换机软件的重要组成部分，本文简要介绍了利用软件工程的方法来开发Ｂ－ＩＳＤＮ用户／网络信令的具体实现方法。     

Broadband ISDN ATM layer management: operations, administration,and maintenance considerations

An overview and characteristics of the broadband integrated services digital network (ISDN) that is based on asynchronous transfer mode (ATM) is presented. ATM layer management across the user network interface (UNI) is discussed. The UNI is described, as are the ATM cell structure and its role in management protocols. There are two management protocol models which are explained; however, the focus is on the ATM layer management protocol. An overview of network management functions is provided. Some examples of ATM layer management functions based on the generic functions are provided     

Leaf Initiated Join handover evaluation

In order to achieve full integration between wired and wireless ATM, a transparent mobile wireless interface to the wired ATM network is required. This paper describes a signalling framework for the handover: the handover is obtained only using standardised UNI 4.0 signalling, without the introduction of mobile specific signalling entities in the fixed network. It is a soft‐forward handover scheme, enabling the handover to comply with the QoS guarantees of the connection. This is achieved using the Leaf Initiated Join (LIJ) capability standardised by UNI 4.0. The handover signalling is proposed taking the propagation characteristics at 60 GHz into account. The evaluation of the performance is performed analytically taking both Poisson and self‐similar traffic into account. The research underlying this paper is performed in collaboration with the ACTS MEDIAN project AC006. This revised version was published online in July 2006 with corrections to the Cover Date.     

Technology interworking for SMDS: from the DXI/SNI to the ATM UNI

As service providers introduce asynchronous transfer mode (ATM) into their networks, they are faced with the issue of technology interworking: for a given service, can a customer who has an ATM user-network interface (UNI) communicate with a customer who does not have an ATM UNI? For switched multimegabit data service (SMDS), technology interworking is well defined. In fact, SMDS is supported by several technology platforms that can interwork with each other. The three major platforms which support SMDS are: a frame-based platform based on the SMDS data exchange interface (DXI), a cell-based platform based on the IEEE 802.6-1990 standard, and a cell-based platform based on ATM. This article examines how SMDS is supported by each of these platforms and how these platforms interwork. Furthermore, this article presents how the major interworking functions required for these platforms appear to be straightforward for suppliers to implement,     

ATM接入信令技术

简要介绍了用于ＡＴＭ网的用户－网络接口令令结构、消息类别和组成以及用户间连接配置和呼叫处理规程。     

宽带ISDN与ATM交换技术第二讲B－ISDN用户－网络接口和协议（下）

宽带ＩＳＤＮ与ＡＴＭ交换技术第二讲Ｂ－ＩＳＤＮ用户－网络接口和协议（下）刘斌（清华大学计算机系北京１０００８４）３ＡＴＭ层前面在介绍ＡＴＭ的基本概念和ＡＴＭ层功能时，已涉及许多有关ＡＴＭ层的内容，这里对一些细节再作补充。简单地讲，ＡＴＭ层的任务就是为...     

Terminal-to-network communication in an ATM-based ISDN

This paper addresses the topic of signalling and connectionless data transfer virtual channels in ATM at the UNI. It recapitulates on the access signalling support in narrowband ISDN, as a representative of an STM network and the predecessor of the coming broadband ISDN. Also, the influence of the customer premises network architecture is taken into account. From there, it is investigated in which ways these principles can be extended, into a general access infrastructure and access configuration management for signalling and connectionless services in the ATM-based broadband ISDN. Some possible implications for the internal architecture of the CPN and the network are discussed. This brings some insight into the restrictions which standardization of these principles at the UNI may bring along for the architecture.     

International standards for the broadband ISDN user-network interface

Recently, a series of international standards on broadband ISDN were approved in CCITT Study Group XVIII. These standards establish fundamental details on transmission, multiplexing and switching for broadband aspects of ISDN. This article reports on the current definition of the BISDN user-network interface. The UNI reference configuration, physical medium, rates, structure, ATM functions, and operations and maintenance functions are addressed with consideration given to open issues and the direction of future standards activities. Objectives for the UNI capabilities have generally been met with the current CCITT specifications. Some of the UNI physical layer ‘options’, however, potentially impose networking cost penalties.     

The ATM Forum's private network/network interface

The ATM Forum completed the first version of its private network/network interface (PNNI) in March 1996 and many ATM switch manufacturers are now offering early implementations. PNNI offers a different type of internetwork or internodal interface from the traditional Signalling System No 7 based approach favoured to date by 'public' network operators, such as BT. In spite of its name, however, PNNI may find its place in network service provider networks as well as in 'private' or customer networks. Some of the perceived limitations of the current specification for such an environment are currently being addressed in version 2, tentatively due for completion in the second half of 1998.The PNNI really consists of two parts, a signalling protocol based around the ATM Forum's UNI signalling specification, and a dynamic source routeing protocol. This paper aims to provide an overview of the functionality and mechanics of PNNI, and to compare and contrast with the functionality offered by ITU-T's B-ISUP.     

ATM Interface Technologies for an ATM Switching System

Realization of the economical, reliable, and efficient ATM interface block becomes an important key to development of the ATM switching system when we consider new issues raised recently. In this paper, we summarize requirements for the ATM interface block and present the UNI (User Network Interface)/NNI (Network Node Interface) architecture to meet these requirements. We also evaluate the performance of the multiplexer adopting the various multiplexing schemes and service disciplines. For ATM UNI/NNI interface technologies, we have developed a new policing device using the priority encoding scheme. It can reduce the decision time for policing significantly. We have also designed a new spacer that can space out the clumped cell stream almost perfectly. This algorithm guarantees more than 99 % conformance to the negotiated peak cell rate. Finally, we propose the interface architecture for accommodation of the ABR (Available Bit Rate) transfer capability. The proposed structure that performs virtual source and virtual destination functions as well as a switch algorithm can efficiently accommodate the ABR service.