Asynchronous transfer mode or synchronous transfer mode or both

Some of the problem areas attendant upon the asynchronous transfer mode (ATM) concept are addressed. Concern is chiefly with the use of small, fixed-length packets and the issue of congestion control. It is argued that broadband ISDN services should not be tied down to ATM as presently standardized, because ATM has several problems when embedded in a wide area network with diverse services     

Asynchronous transfer mode: the ultimate broadband solution

Asynchronous transfer mode (ATM) is a new telecommunications technology which is being developed and standardised for use with broadband services. This tutorial paper describes the main features of ATM     

Asynchronous transfer of video

Video transfers across IP and ATM networks have received much research attention during the last ten years. Various video services are expected in the future, enabled by the rapid development in video coding and broadband network technology. This article gives an introduction to the issues involved in asynchronous video transfers. Brief overviews of video coding, rate control, and multiplexing, as well as delay, error, and loss control are also given     

Asynchronous transfer mode (ATM) operation via satellite: Issues,challenges and resolutions

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.     

Asynchronous transfer mode switching LSI chips with 10-Gb/s serialI/O ports

LSI chips were developed that fit on a switching fabric using chip-to-chip optical interconnections; they have 10-Gb/s serial input and output ports, which facilitates the layout of optically interfaced switching element modules. A test switching module composed of these chips was operated at 10.2 Gb/s without bit errors. Ultrahigh-speed switching LSI chips have been developed for a future asynchronous transfer mode (ATM) switching system with an over-Tb/s capacity. Their serial input and output ports facilitate chip-to-chip optical interconnection. Cell-dropper and crosspoint-router LSI chips, composing the core of the switching element, were fabricated by using GaAs LSI technology. A test switching module composed of these chips was operated at 10.2 Gb/s without bit errors     

Asynchronous sequential machines with request/acknowledge operating mode

A method for the synthesis of asynchronous sequential machines that leads to a realisation directly obtained from the flow graph (or flow table) is described. Each state of the system is materialised with a memory element designed in such a way that the state transitions operate in a request/acknowledge mode. The consequences are that the sequential network is hazard free and only the input transfer functions need to be generated.     

Networking a la mode [asynchronous transfer mode]

The asynchronous transfer mode (ATM) was developed at the behest of the telecommunications industry, but is being deployed principally within private data networks. In this paper, the author explains this apparent paradox     

改进的CBC 模式及其安全性分析

针对CBC模式在分块适应性攻击模型下不安全这一问题,提出了一个新的分组密码工作模式。新方案引进了Gray码,改变了原有模式的输入方式,打乱了前后输出输入的内在联系。同时,利用规约的思想对其安全性进行了分析。结果表明,在所用分组密码是伪随机置换的条件下,方案在分块适应性攻击模型下是可证明安全的。     

Electronic funds transfer security: a network-optimised approach

A network-optimised approach to electronic funds transfer at point-of-sale is described which gives excellent system flexibility, growth capacity and cryptographic operation. End-to-end cryptographic security techniques are examplified for illustrative message protocols and PIN verification strategies.     

Packet power-B-ISDN and the asynchronous transfer mode

The vast expense of installing a new infrastructure for the ISDN has now been accepted. The new type of network should be able to carry not only existing services of voice communication, but also those that might be needed well into the future such as data, facsimile and pictures. The authors discuss the use of the broadband ISDN with the asynchronous transfer mode based on fast packet switching     

Output-buffer switch architecture for asynchronous transfer mode

This paper proposes a new asynchronous transfer mode (ATM) switch architecture for the broadband ISDN. The ATOM switch ATM output-buffer modular switch has a multi-stage network structure, and is highly modular to facilitate capacity expansion. The ATOM switch element is of the output-buffer type with a time-division multiplexed bus and FIFO buffer for each outgoing line. Bit-slice techniques are used to implement the high-speed time-division bus and buffer memories. The output buffer switch has the advantages of no throughput degradation since internal contention is eliminated, and a simple control structure for providing priority and multi-point connections. This paper also deals with switching delay and buffer overflow probabilities for mixed (bursty and non-bursty) traffic.     

基于卷积神经网络的安全防御模式研究

计算机网络在为人们提供各种便利服务的同时也面临着许多的安全威胁,如木马或病毒等.不法分子通过网络攻击,破坏网络服务和用户数据,为人们带来严重的威胁.网络安全专家和企业机构提出了很多安全防御技术,一定程度上提高了网络安全防御能力,但是随着互联网数据和流量的快速增加,网络攻击的种类和数量呈现出指数级增长,急需提出新的防御技...     

基于预约诊疗模式下的医院网络安全设计

针对在预约诊疗模式下医院网络的安全性不强,容易导致病人隐私信息泄露的问题,进行医院网络安全设计,基于隐私保护路由协议,提出预约诊疗模式下的医院网络安全设计方法。首先构建医院网络体系结构模型,设计预约诊疗模式下的医院网络路由协议;然后采用网络诊疗信息融合方法进行隐私保护设计,实现医院网络安全设计;最后通过仿真实验进行性能测试。仿真实验结果表明,构架的预约诊疗模式下的医院网络模型对病人的隐私信息保护能力较强,说明抵御攻击性能较好,保障了医院网络安全。     

云计算应用模式下移动互联网安全问题分析

随着我国科学技术的不断发展和进步,越来越多的用户利用移动终端来对互联网进行了访问,并且进行了信息的获取以及发送.在此种情况下,云计算也逐渐的融入到了人们的生活当中,移动互联网的安全问题得到了社会各界的广泛关注,因此需要对云计算应用模式下的移动互联网的安全问题进行全面的分析.本文首先对云计算的应用进行了概述;其次对移动互联网应用架构下的云计算安全风险与安全体系做出了分析;最后在移动互联网当中的安全问题进行了理性的思考.     

Variable rate speech coding for asynchronous transfer mode

A new speech coding and multiplexing scheme matched to the asynchronous transfer mode is described. A block coding technique that is based on a variable-rate coding algorithm that makes the most of the burstiness of voice information is employed. The main feature of the scheme is considerable bit reduction, which is attained by a fairly simple algorithm. It is demonstrated that the proposed algorithm exhibits better quality than that of a 32 kb/s ADPCM at a mean bit rate of less than 13 kb/s. The effect of statistical multiplexing is verified by means of simulation employing long conversational speech samples. Methods for constructing variable- and fixed-length frames (units of information multiplexed and transferred in the network) are proposed. The proposed coding algorithm is shown to be applicable to both variable- and fixed-length frame strategies     

A novel bus transfer mode (AS transfer) and a performance evaluation methodology

This paper proposes an innovative on-Chip bus transfer mode – the Advanced Encryption Standard (AES) state transfer (AS) and a performance evaluation methodology to estimate the transfer performance. By modeling and collecting several performance metrics including bus latency, bandwidth, valid bandwidth, power and energy consumption using the methodology, it enhances fidelity of the performance analysis and evaluation. As a case study, we formally complete the hardware implementation flow on Advanced High-Performance Bus (AHB), Advanced eXensible Interface 4 (AXI4) and AS bus (ASBUS) DMA, and demonstrate high estimation accuracy by comparing all the experimental results. Both static analysis and hardware implementation results show that the data transfer latency is close to 29% of AHB and 58% of AXI4 by using the AS transfer. Moreover, it is observed that this high-efficiency transfer mode of ASBUS helps to enhance the valid data bandwidth to around 3.4 times that of AHB and 1.7 times that of AXI4, and the energy consumption of ASBUS is only a half of AHB and AXI4. Furthermore, the proposed evaluation methodology is effectively used with sufficient accuracy (the average estimation error: 3.3%) in the design flow.     

银行卡网上支付安全认证模式分析

2.SecureCode 万事达于2002年9月推出了新的网上交易方式——SecureCode,适用于MasterCard 和Maestro 品牌的信用卡和借记卡,它利用了UCAF(此隐藏域为持卡人的认证信息)域和SPA算法(基于发卡行的远程交易安全方法)。为了支持VISA的3-D,它还提供了一种3-D的认证方式,修改了3-D的部分内容来兼容UCAF和SPA运算,但对其定义、消息、协议未做任何改变。下面分别讨论这两种模式。     

Broadband ISDN and asynchronous transfer mode (ATM)

The transfer mode chosen by the CCITT Study Group XVIII Task Group on ISDN Broadband Aspects as the basis of broadband ISDN is called the asynchronous transfer mode (ATM). ATM is a high-bandwidth, low-delay, packetlike switching and multiplexing technique. It is essentially a connection-oriented technique, although it is envisioned as a basis for supporting all services, connectionless as well as connection-oriented. The basic transfer mode concepts are explained. The limits of synchronous transfer mode (ATM) are discussed and reasons for choosing ATM over STM are given. The main technical issues having an impact on the ATM specifications are discussed     

CW and pulsed mode transfer impedance measurements in coaxialcables

Transfer impedance measurements have been performed both in frequency and time domains. CW measurements were performed using a matched triaxial system, a quintaxial system, and stripline injection. For nuclear electromagnetic pulse (NEMP) purposes, measurements up to a maximum frequency of 200 MHz are sufficient. For this frequency range the matched triaxial system was found to be the most convenient. Amplitude and phase measurements in different cables are discussed. Direct and indirect injection was employed in the time domain measurements. A delayed coupling is demonstrated when the diffusion term is dominant in the transfer impedance. In a magnetically shielded cable, hysteresis and saturation effects have been observed. At 5 kA the transfer impedance of the magnetically shielded cable increased by an order of magnitude due to saturation