Performance analysis of customer access to an ISDN

A simple analytical model has been developed to quantify the performance encountered by voice and data traffic during customer access to an ISDN. This enables a direct comparison of traffic capabilities of various proposed implementation schemes currently under consideration by telecommunications administrations.     

使用ST-BUS总线实现ISDN体系结构

本文简要介绍ISDN的基本概念、特征及主要构成部分,同时介绍了ST-BUS总线结构,具体描述如何使用ST-BUS总线结构来实现ISDN的体系结构。     

Design of integrated data/voice stations for a CSMA/CD LAN

This paper describes the design and implementation of integrated data/voice stations for a LAN environment. The stations are based on the DB16000 Development Board using a 16-bit CPU. Continuously variable slope delta modulation is selected as the voice encoding technique. Protocols were designed and implemented to handle data and voice separately. Prototypes were built to test the station's performance. The stations communicate with one another at a rate of 1.5 Mbit/s. The voice digitization rate is 16 kbit/s and the terminal speed is 9.6 kbit/s.     

ISDN中2B+D转USB网络接口设备的实现

ISDN终端产品能独立实现数字电话、传真、图文、视频等多种功能。如果将PC机虚拟成ISDN终端,就可以利用PC机丰富的软硬件资源融合ISDN终端产品的各种功能。文章分析了电信网中的ISDN2B--DU数字用户接口单元和USB协议框架,提出了一种实用的ISDN2B--DU接口转USB网络接口的实现方案,实现了NT1产品和USB主机通信,从而大大扩展了ISDN的服务领域。     

VSAT卫星通信网与ISDN互连的几个问题

本文主要介绍卫星广域网(SWAN)的组成与应用,TCP/IP协议,VSAT网与ISDN互连的几个问题。     

ISDN基本速率接入技术研究

本文提出了一种实现ISDN基本速率接入的方法并阐述了其基本原理。     

Standardized TTCN-3 specifications for SIP-ISUP/ISDN interworking testing

ETSI technical committee TISPAN currently funds the development of TTCN-3 network integration test suites using TTCN-3. Specialist task forces (STF) have already been initiated to implement and validate abstract test suites focusing on, e.g., SIP/ISUP and SIP/ISDN interworking units. In this paper, we report on our implementation approach and experiences made in the STF on testing interworking between SIP and ISDN/ISUP. Special attention has been given to the reuse of know-how and of existing TTCN-3 code available due to the existing SIP conformance test suite and the TTCN-3 test framework developed by ETSI for IPv6. Validation has been done using the test laboratory of a telecom network provider.     

A two-layer congestion control protocol for broadband ISDN

In this paper, we present a new, effective connection-oriented congestion control protocol for B-ISDN. The protocol employs the traffic viewpoint hierarchical design approach and is implemented by a two-layer scheme at the call and cell layers. The call layer handles call admission (denial) and provides shortest path connection routing when a call is admitted, while the cell layer allocates switch input buffer space for each traffic type according to each type's cell loss probability grade-of-service requirement. There is a direct interaction between the two layers in processing a connection request. A discrete-time queueing system with geometrically distributed service time and state-dependent Markov modulated Bernoulli process (MMBP) arrivals is established to model heterogeneous networking environments for this protocol and an analytical solution is developed for this queueing system. Numerical results obtained by both analysis and simulation show that the protocol can reduce network congestion as input traffic rates approach switch capacity and, thereby, increase network utilization relative to that possible in the absence of congestion control.     

Protocol implementation for Universe

The communications protocols used on the Universe network and the implementor's experiences with them are described. By examining ‘lightweight’ and ‘heavyweight’ protocols, the paper examines the problems of protocols for mixed networks.     

矿井多媒体综合业务数字网关键技术的研究

首次提出矿井多媒体综合业务数字网的实施方案及其基本要求 ,对矿井多媒体综合业务数字网络系统的结构模型及其关键技术进行了深入的研究 ,讨论了其基本原理及功能 ,并研究与设计了矿用本安型网络智能分站、矿用隔爆兼本安型网络交换机、矿用本安型网络视频服务器、矿用本安型IP网络电话     

LANs in an ISDN: consistency with the OSI Reference Model

When LANs are connected to an ISDN, different problems arise, especially when attempting to comply with the OSI Reference Model of the ISO. Different solutions to these problems are proposed with their specific advantages and drawbacks. The choice between these different proposals will depend on the effort a user is prepared to make. The paper emphasizes the introduction of a subsection of the network layer: the internet layer.     

An X.25-compatible protocol for packet voice communications

Developments in packet-switched networks have generated interest in how to integrate voice and data traffic in such networks. The paper deals with a proposed communications protocol for voice transmission within X.25 packet-switched networks. Basic protocol procedures for handling voice communications are examined, and possible formats for the identified types of voice frame and packet fitting for current CCITT standards governing packet data communications are presented.     

Proposed high speed packet switch for broadband integrated networks

The design of a high speed, broadband packet switch with two priority levels for application in integrated voice/data networks is presented. The packet switch can efficiently cope with 128 byte packets converging on it from eight 140 Mbit/s dynamic time division multiplexed fibre optic links. The packet switch throughput varies with the load and traffic composition, and the delay experienced by voice and data packets is within 300 μs and 3 ms, respectively. The design is implemented by task-sharing in a multi-processor configuration. The design of the packet switch, including its subsystems, is detailed here.     

ISDN在面向定做式人工关节的敏捷制造系统中的应用

本文针对面向定做式人工关节的敏捷制造系统中信息交流的需要,讨论了ＩＳＤＮ的优势及ＩＳＤＮ接入ＩＮＴＥＲＮＥＴ的实现,并介绍了ＩＳＤＮ在这个系统中的应用。     

新型电信诈骗案件中的电子数据研究

近年来,电信诈骗手段花样不断翻新,方式越来越隐蔽。新型电信诈骗案件具有智能化、高隐蔽性和组织化等突出特点。通过远程控制软件从受害人计算机上把钱直接从受害人账户上转走,是电信诈骗案件发展的一个新趋势。有效分析、搜索、提取该类电信诈骗案件中的电子数据能为侦查破案提供重要线索,为起诉审判提供证据支撑。     

An efficient location-based compromise-tolerant key management scheme for sensor networks

Location information has been paid much more attention in sensor network key management schemes. In 2006, Zhang et al. proposed a location-based key management scheme by binding private keys of individual nodes to both their identities and locations. In this Letter, however, we show that their scheme cannot resist key compromise impersonation (KCI) attack, and does not achieve forward secrecy. In fact, an adversary who compromises the location-based secret key of a sensor node A, can masquerade as any other legitimate node or even fake a node to establish the shared key with A, as well as decrypt all previous messages exchanged between A and its neighboring nodes. We then propose a new scheme which provides KCI resilience, perfect forward secrecy and is also immune to various known types of attacks. Moreover, our scheme does not require any pairing operation or map-to-point hash operation, which is more efficient and more suitable for low-power sensor nodes.     

基于WSNs的井下应急语音通信系统的研究

针对目前井下语音通信系统的现状,设计了一种基于无线语音传感器网络的矿井应急语音通信系统,该系统以SPCE061A和CC2420芯片为核心设计传感器节点,结合CAN控制器SJA1000设计Sink节点,并对网络通信协议进行了分析,给出了系统的硬件设计和软件流程。克服了传统有线网络的局限性,避免了其他无线通信技术高功耗的缺点。实验表明:该系统简单、可靠、经济,具有很好的应用前景。     

Local networking at the Royal Bank of Scotland

Data communications facilities are vital if essential banking operations are to be computerized; branches and head offices that are dependent upon terminals and corporate data to fulfil their functions must have access to such facilities. Back-up facilities are also essential if normal bank functions are not to be disrupted should a fault develop. Investigations that led to the installation of Hyperchannel at the Royal Bank of Scotland are described and the problems to which Hyperchannel provided the solutions are examined. The implementation of the system and plans for future development are discussed.