Classical IP Over ATM规范(下)

ＡＴＭ（异步传输模式）技术是目前最受人瞩目的高速网络技术之一，而如何使ＡＴＭ网络与现有的网络协议（如ＴＣＰ／ＩＰ）相结合是ＡＴＭ技术发展的关键性问题。本文通过对比分析了在ＡＴＭ局域网与传统局域网上ＩＰ协议实现的异同，并较为深入地介绍了在ＡＴＭ上运行ＴＣＰ／ＩＰ协议的技术方案。     

Classical IP Over ATM规范(上)

ＡＴＭ（异步传输模式）技术是目前最受人瞩目的高速网络技术之一，如何使ＡＴＭ网络与现有的网络协议（如ＴＣＰ／ＩＰ）相结合是ＡＴＭ技术发展的关键性问题。本文通过对比分析了在ＡＴＭ局域网与传统局域网上ＩＰ协议实现的异同，并较为深入地介绍了在ＡＴＭ上运行ＴＣＰ／ＩＰ协议的技术方案。     

TCP／IP协议在ATM网上的运用

当前广泛使用的ＴＣＰ／ＩＰ协议与未来潮流的ＡＴＭ结合到一起，是一个带有战略性的技术课题。本文就ＴＣＰ／ＩＰ协议的基本体系结构、ＡＴＭ信元与适应层、ＩＰ在ＡＴＭ网上运用的基本体系结构模型、地址分辨、连接管理等各个侧面进行轮廓性的探讨。     

TCP／IP协议在ATM网上的运用

当前广泛使用的ＴＣＰ／ＩＰ协议与未来潮流的ＡＴＭ结合到一起，是一个带有战略性的技术课题。本文就ＴＣＰ／ＩＰ协议的基本体系结构、ＡＴＭ信元与 适应层、ＩＰ在ＡＴＭ网上运用的基本体系结构模型、地址分辨、连接管理等各个侧面进行轮廓性的探讨。     

基于TCP／IP协议的业务在ATM网络中的流量控制

由于ＴＣＰ／ＩＰ协议在计算机通信网络中的广泛应用，使得基于ＴＣＰ／ＩＰ协议的业务在ＡＴＭ网络中的透明传输成为一个重要问题。为了控制这种业务的流量，人们提出了具有反馈机制的基于速率的控制方法和快速保留协议方法。本文在阐述这两种方法不足的基础上，提出了一种新的流控机制，使基于ＴＣＰ／ＩＰ协议的业务在ＡＴＭ网络中更高效率地传输。     

TCP/IP在ATM网络中的性能分析和优化

分析了造成ＴＣＰ／ＩＰ在ＡＴＭ上性能低的原因,以提高链路利用率和吞吐量为目的对ＴＣＰ协议进行了改进,提出了两种解决方法：反馈重传策略和分组级的流量成形,来提高ＴＣＰ／ＩＰ在ＡＴＭ网络上的性能。     

Internet协议的最新发展

Ｉｎｔｅｒｎｅｔ协议的最新发展邮电部数据通信技术研究所史习军，陈锦章一、ＴＣＰ／ＩＰ与ＩＳＯ／ＯＳＩＴＣＰ／ＩＰ源于六、七十年代的ＡＲＰＡＮＥＴ，并于１９７７～１９７９年之间制定出ＴＣＰ／ＩＰ体系结构和协议标准。２０年来，基于ＴＣＰ／ＩＰ的Ｉｎｔｅｒ...     

TCP／IP路由器的实现

ＴＣＰ／ＩＰ路由器的实现范妮，高锡武，马跃ＡＰＰＡ网上的ＴＣＰ／ＩＰ协议是为了将许多实际分开的网络互连起来，在功能上成为一个整体而提出的网际技术。这种技术把网络硬件细节遮掩起来，从而允许计算机进行通信而与它们的网络物理连接无关。ＴＣＰ／ＩＰ协议是一组...     

TCP／IP的网络体系结构和协议机制

ＴＣＰ／ＩＰ的网络体系结构和协议机制张国清Ｉｎｔｅｒｎｅｔ遵循ＴＣＰ／ＩＰ的网络体系结构和协议机制。本文着重介绍ＴＣＰ／ＩＰ的网络体系结构和特点、协议集功能及其协议机制。一、ＴＣＰ／ＩＰ的形成与发展１９６９年美国国防部高级研究计划署（ＤｅｆｅｎｃｅＡ...     

谈谈数字网络通信中的TCP／IP协议

本文对上前使用广泛的数字通信协议ＴＣＰ／ＩＰ进行了全面的的介绍，并对ＴＣＰ／ＩＰ协议的构成、主要功能及物理介质与应用程序之间关系作了详细介绍，对我们全面了解和运用ＴＣＰ／ＩＰ协议很有用处。     

NASA's broadband satellite networking research

ATM is currently considered the primary WAN technology with Internet protocols providing the routing and transport requirements. Another WAN technology being considered is packet over SONET. Using the Advanced Communication Technology Satellite, NASA has demonstrated and is experimenting with these technologies. This article summarizes some of the major completed and ongoing experiments and demonstrations performed using commercial standard protocols such as ATM and TCP/IP over broadband satellite networks     

How a large ATM MTU causes deadlocks in TCP data transfers

The implementation of protocols, such as TCP/IP, and their integration into the operating system environment is crucial for protocol performance. Putting TCP on high-speed networks, e.g., ATM, with large maximum transmission units causes the TCP maximum segment size to be relatively large. What Nagle's algorithm considers a “small” segment is no longer small, which affects the TCP performance. The authors report on TCP/IP throughput and RPC response time performance measurements for various sizes of send and receive socket buffers, using the Sparc10 architecture machines Axil 311/5.1 running SunOS 4.1.3 connected to a FORE System's ATM network. For some common combinations of socket buffer sizes the authors observe a dramatic performance degradation to less than 1% of expected throughput and to one order-of-magnitude longer response time than expected. The performance degradation is caused by a deadlock situation in the TCP connection which is resolved by the 200 ms spaced timer generated TCP delayed acknowledgment. The authors explain the causes of the deadlock situations, and discuss means to avoid or prevent them     

ATM局域网性能测试与分析

异步传输模式（ＡＴＭ）常被认为是一种解决网络带宽瓶颈的技术，但是应用程序从ＡＴＭ网络获得的带宽受到许多因素的限制。本文通过在ＣＥＲＮＥＴ的ＡＴＭ测试床上的实验，对基于ＡＴＭＡＰＩ的数据交换和基于ＴＣＰ／ＩＰ／ＡＴＭ的数据交换进行了对比。结果表明，原始的ＡＴＭ信元交换其效率是非常好的，但在不同协议栈上的应用所能获得的带宽受系统软件、传统的网络协议和端系统等诸多方面的限制。通过调整这些因素，可以提高应用程序可获得的带宽。     

Proxy PNNI Augmented Routing (Proxy PAR)

ATM networks often carry other popular communication protocols such as TCP/IP. LAN emulation techniques, with LANE and MPOA being the most prominent ones, make it possible to support existing applications, but do not take advantage of many ATM capabilities. Furthermore, such server-based solutions often suffer from single point of failure problems. PNNI Augmented Routing (PAR), based on Private Network–Network Interface (PNNI), enables ATM and TCP/IP to be better integrated than in an emulation environment. In addition to that, Proxy PAR has been introduced as a minimal version of PAR that gives ATM-attached devices the ability to interact with PNNI devices without the complexity associated with a full PAR implementation. Proxy PAR has been conceived as a client/server interaction in which the client side is much simpler than the server side, permitting fast implementation and deployment in existing IPv4 devices. The main purpose of Proxy PAR is to allow non-ATM devices to use the flooding mechanisms provided by PNNI for registration and automatic discovery of services offered. Proxy PAR capable servers support filtering based on Virtual Private Network (VPN) IDs, IP protocols and address prefixes. This enables, for example, routers in a certain VPN running OSPF to find their neighboring routers without the manual configuration implied by other technologies such as Frame Relay. This revised version was published online in August 2006 with corrections to the Cover Date.     

Performance evaluation of TCP extensions on ATM over high bandwidthdelay product networks

Practical experiments in a satellite network environment assist in the design and understanding of future global networks. This article describes the practical experiences gained from TCP/IP on ATM networks over a high-speed satellite link and presents performance comparison studies of such networks with the same host/traffic configurations over local area and wide area networks. These comparison studies on the LAN, WAN, and satellite environments increase our understanding of the behavior of high-bandwidth networks. NASA's Advanced Communications Technology Satellite (ACTS), with its special characteristics and high data rate satellite channels, and the ACTS ATM Internetwork (AAI) were used in these experiments to deliver broadband traffic. Network performance tests were carried out using application-level software (Netspec) on SONET OC-3 (155.52 Mb/s) satellite links. Finally, we experimentally study the performance, efficiency, fairness, and aggressiveness of TCP Reno, TCP New Reno, and TCP SACK end hosts on ATM networks over high BDP networks     

Performance and buffering requirements of Internet protocols overATM ABR and UBR services

ATM networks are quickly being adopted as backbones over various parts of the Internet. This article studies the dynamics and performance of the TCP/IP protocol over the ABR and UBR services of ATM networks. Specifically the buffering requirements in the ATM switches as well as the ATM edge devices. It is shown that with a good switch algorithm, ABR pushes congestion to the edges of the ATM network while UBR leaves it inside the ATM portion. As a result, the switch ABR buffer requirement for zero-packet-loss high-throughput TCP transmission is a sublinear function of the number of TCP connections     

Scalable QoS-based IP multicast over label-switching wireless ATMnetworks

A Mobile IP multicast prototype that integrates a label-switching wireless asynchronous transfer mode, the mobile core-based multicast architecture, and an Internet multicast infrastructure is presented. MCOM creates multiple core-based layer 2 multicast trees that are independently established in member networks. They are interconnected via the Internet using layer 3 multicast routing. Gateways on the border of the Internet and wireless ATM networks convert ATM multicast traffic to suitable IP packets as well as converting from IP packets to ATM cells for MCOM. To solve the cell interleaving problem that results, ATM block transfer/immediate transmission capability is reasonably modified. Additionally, class-based block buffer management for ATM multicast connections is built into wireless ATM switches for soft quality of service control. Dynamic group management, multicast channel rerouting, and reliable multicasting are also studied in relation to existing Internet protocols like Mobile IP, Internet group management protocols, and multicast routing protocols     

Dynamically selecting protocols for socket applications

An application enablement method that enables communications applications to run on protocols for which they were not written is discussed. The focus is on a subset of networks and communications application programming interfaces. The communications interface chosen is Berkeley sockets. The network protocols used are SNA (Systems Network Architecture) and TCP/IP (Transmission Control Protocol/Internet Protocol). The running of existing socket applications over SNA networks, which requires support for transparently masking the differences between TCP/IP and SNA from the applications, is described. Protocol selection, address mapping, and connection management are also described     

Modelling and analysis of routing and resource allocation techniques in multi‐service networks

In this paper a novel call level model based on the extension of the classical Erlang multi‐rate model for broadband integrated services networks is proposed. We use the model to study routing strategies in multi‐service networks where service classes with/without QoS guarantees coexist. Examples for such networks include ATM and IP‐based integrated networks. In ATM, the CBR and VBR service classes provide QoS guarantees, while the ABR and UBR service classes are of the best effort type. In IP, traditional TCP/IP traffic is of the best effort type, while new protocols like the RSVP or the differentiated services with central resource handling attempt to support QoS parameters. The coexistence of guaranteed and best effort traffic gives rise to new challenging problems since for a given elastic (best effort) connection the bottleneck link determines the available bandwidth and thereby puts constraints on the bandwidth at the other links along the connection's path. Since the available bandwidth fluctuates in time following the load on the links, routing and link allocation in this environment together with blocking probability calculations and fairness issues need to be studied. By means of our proposed model we are able to conduct a survey of various routing and link allocation techniques as well as to develop a modified shortest path routing algorithm which, according to the numerical examples, performs well in this environment. Copyright © 1999 John Wiley & Sons, Ltd.     

TCP／IP环境下的OSI协议栈的构建

ＴＣＰ／ＩＰ是当前广泛采用于各种网络中的一种网络体系，它是目前事实上的网络标准。ＯＳＩ则是ＩＳＯ制定的网络体系结构国际标准。从网络现状出发实现一个基于ＴＣＰ／ＩＰ的ＯＳＩ协议环境是很有意义的。本文较为详尽地介绍了该环境的实现，并给出了在ＴＰ２上ＯＳＩ高层协议实现的通用模式。