一种替代路由器的经济办法

路由器是ＯＳＩ／ＲＭ网络结构中属于网络层的进行网络寻址和流量控制的设备,在多个ＬＡＮ之间或者ＬＡ与ＷＡＮ之间不可或缺,但价格较贵。本文介绍一种利用ＮＴ相关功能,在ＬＡＮ／ＷＡＮ和Ｉｎｔｅｒｎｅｔ上实现路由功能的技术。     

Alternative software architectures for parallel protocol executionwith synchronous IPC

The use of parallelism in enhancing protocol execution performance is examined. In particular the use of a separate concurrent task for each protocol layer is discussed. Two layers of the OSI protocol system were implemented and run on a multiprocessor, with from one to five processors at each end of the connection. Potentially concurrent entities included user tasks as data source and sink, the OSI session layer (kernel functional unit only), the OSI transport layer (classes 0 and 2), vestigial network tasks, and tasks to buffer data between layers. Three substantially different design architectures with from nine to twelve tasks at each end of the connection were compared. The design differences centered on different ways to provide interlayer coordination and buffering; the protocol code was kept identical. The implementation used a real-time kernel which provides synchronous (request-reply) interprocess communication. The variation in throughput between designs covered a range of approximately two to one. The best design is found to be symmetrical decentralized two-way pipeline with courier communications     

Analyse des fonctions des protocoles ipsec et leur intégration dans un réseau privé virtuel

Many approaches may lead to integrate security functions in the intranet/internet services. These functions may be placed at the application layer or at lower OSI layers. IPsec suite protocols were specified by IETF in order to integrate security functionality at network layer. This paper describes the features of IPESC protocols and identifies the aspects which are not standardized. The network translation address (nat) functionality used by routers and firewalls is not always compatible with IPESC. We describe and discuss some solutions for the compatibility of ipsec and nat. The last part of this paper describes a typical architecture for ip vpn based on IPSec technology.     

Omissions and ambiguities in CCITT Recommendation Q.921

The data link layer protocol for the integrated services digital network (ISDN) user/network interface, known as link access protocol-D (LAPD), is a protocol that operates at layer 2 of the open systems interconnection (OSI) architecture. Its purpose is to safely convey information between layer 3 entities using the D-channel. The information types that LAPD is intended to transport include call control signaling, packet mode communications, and management information. Observations are made in this article about what are, in the authors' opinion, the most confusing points of CCITT Recommendation Q.921 with comments related to data link layer address field, broadcast connections, terminal endpoint identifier (TEI) management procedures, layer 2 frames exchange, and connection management entity response to MDL-error indication primitives. This article intends solely to clarify the recommendations so that their concepts and procedures become easier to understand and implement, which can lead to significant saving of time for those who must eventually use LAPD procedures or develop the software for handling them     

Evaluation of CDMA2000 support for IP micromobility handover andpaging protocols

Research in Mobile IP has proposed that IP should take support from the underlying wireless network architecture to achieve good performance for handover and paging protocols. The IETF work defines requirements for layer 2 (the data link layer of the OSI model) to support optimized layer 3 (the network layer of the OSI model) handover and paging protocols. Layer 2 can send notification to layer 3 that a certain event has happened or is about to happen. The notification is sent using a trigger. We list the triggers needed by IP handover and paging protocols. We map the triggers to their corresponding events in CDMA2000     

Lightpath routing for intelligent optical networks

An overview of current issues and challenges in lightpath routing for optical networks is given. An architecture is presented in which optical switches are deployed, usually in the core, to interconnect IP routers at the edges. Lightpath routing within this architecture follows the framework of generalized multiprotocol label switching. Our discussion pays particular attention to the aspects of optical routing that differ from routing in irrational IP networks. Such aspects include physical layer constraints, wavelength continuity, the decoupling of the control network topology from the data network topology, explicit routing with wavelength assignment, and diversity routing for fast protection. We also present an algorithmic framework for lightpath computation, highlighting the issue of wavelength continuity and the differences between lightpath computation and traditional IP route computation     

Choosing the appropriate ISO layer for LAN interconnection

The authors discuss the technical ramifications involved in the choice between interconnecting local area networks with a layer 3 (ISO network layer) versus layer 2 (ISO data link layer) approach, that is, routers versus bridges. They consider the distinction between two layers and define routers and bridges. They then argue the case for each. They conclude that neither approach is better, in the sense that each has its appropriate problem space, and suggest a mixture of relays     

多路ISP和多种类出口设备融合控制研究

网络的融合给整个通信产业链带来了巨大的机遇和挑战,是未来发展的趋势。网络的融合给整个通信产业链带来了巨大的机遇和挑战,是未来发展的趋势。真正的融合型设备组必须满足一条标准,那就是从功能和应用上,取代位于网络核心层的所有设备——包括路由器、防火墙、IDS/IPS检测、防垃圾邮件产品等,同时能将以太网交换机、IDS、防病毒网关、防火墙这些分属于不同层面的设备实现联动达成内部上网行为安全管理。基于OSI模型对网络及设备融合进行了分析,设计了立足于社区或大学城模式的融合案例,对兼容性分析和设备配置提出了自己的见解。     

Public-key cryptography and open systems interconnection

The role of public-key cryptography in open systems interconnection (OSI) is discussed. A short tutorial introduction to public-key cryptography is followed by a discussion of how security fits into the OSI architecture, and what standards are being developed in this area. The use being made of public-key cryptography in the network layer and in the message handling system and directory application is also discussed     

Implementing OSI-based interfaces for network management

Experience acquired in the development of an interface between a fiber optic system and a prototype management system developed using an object-oriented approach is discussed. Open System Interconnection (OSI) implementation concerns, the use of an ASN.1 compiler, and the use of standard application programming interfaces (APIs) are described. The role of the seven-layer OSI stack in exchanging information between managing operating systems and managed network elements is reviewed. The implementation of an OSI stack on a SUN workstation using the UNIX operating system is also described. Methods for passive and active testing of the resulting programs are discussed     

A multiprocessor approach for meeting the processing requirementsfor OSI

To meet the increased communication processing requirements of high-speed networks, a multiprocessing network interface is considered for processing multiple layers of a communication protocol stack. In particular, the processing of the open systems interconnection (OSI) layers 2 to 6 on the network interface are considered. OSI processing is computationally expensive because of the inclusion of the transfer syntax conversion at the presentation layer. The approach taken is to process different packets in parallel. The results obtained from simulations indicate that the approach has promise for OSI processing at higher rates     

一种基于CNN的无线路由器指纹识别方法

针对无线设备"指纹"特征提取技术含量较高，且技术手段较为复杂的问题，在无线空间信道状态不变的前提下，提出了一种基于卷积神经网络（convolution neural network，CNN）自动分类无线路由器指纹的识别方法，解决无线设备"指纹"特征提取困难的问题.文章设计并实现了一种通过接收处理多输入多输出（multiple-input multiple-output，MIMO）信号幅度识别无线路由器的方法，该方法通过采集无线路由器的信道状态信息（channel state information，CSI），并对CSI的幅度数据进行预先平滑和去噪处理，然后把预处理后的幅度数据作为设备的指纹特征，最后通过机器学习的算法进行分类和识别.实验采用CNN对10台商用无线路由器进行分类和识别，准确率达到96%以上，证明了使用CSI来识别无线路由器是可行的.     

Ethernet-Based Real-Time and Industrial Communications

Despite early attempts to use Ethernet in the industrial context, only recently has it attracted a lot of attention as a support for industrial communication. A number of vendors are offering industrial communication products based on Ethernet and TCP/IP as a means to interconnect field devices to the first level of automation. Others restrict their offer to communication between automation devices such as programmable logic controllers and provide integration means to existing fieldbuses. This paper first details the requirements that an industrial network has to fulfill. It then shows how Ethernet has been enhanced to comply with the real-time requirements in particular in the industrial context. Finally, we show how the requirements that cannot be fulfilled at layer 2 of the OSI model can be addressed in the higher layers adding functionality to existing standard protocols.     

基于FMC标准的万兆以太网卡

结合FMC标准与IEEE 802.3ae协议标准,设计了一种基于FPGA夹层卡(FPGA Mezzanine Card,FMC)标准的万兆以太网卡,满足现代工业大数据量传输应用的要求。FMC标准接口可实现多通道高速接口,解决应用母板与网卡之间的数据传输瓶颈。使用Verilog硬件描述语言设计了地址解析协议(Address Resolution Protocol,ARP)与用户数据报协议(User Datagram Protocol,UDP)的硬件协议栈,实现开放式系统(Open System Interconnect,OSI)模型的传输层;Xilinx 10 G Ethernet subsystem IP与小型化可热插拔(Small Form-factor Pluggable,SFP)光接口实现OSI模型的网络层、数据链路层、物理层。通过FMC母板、万兆以太网卡、PC上位机组建的网络成功测试了万兆以太网通信。     

CMISE functions and services

The common management information service element (CMISE), an application service element (ASE) developed to support the management application of the Open Systems Interconnection (OSI) applications layer, is discussed. It was developed in response to the need to monitor and control the health of OSI communications entities. Similarly, the simple network management protocol (SNMP) was developed in the Internet community to manage network resources. Although CMISE was developed to manage resources such as OSI protocol entities, its applicability in managing the telecommunication network elements has been accepted in CCITT and ANSI T1 standards because of its powerful features     

B-ISDN and the OSI protocol reference model

The evolution of public telecommunication networks toward broadband integrated services digital networks (B-ISDNs) is presented. The asynchronous transfer mode (ATM), which supports B-ISDNs, and the B-ISDN protocol reference model are discussed. It is shown that the service offered by the ATM layer in the B-ISDN protocol reference model is equivalent to the service offered by the OSI physical layer. It is also shown that the service offered by the ATM adaptation layer (AAL) type 3/4 is similar to an OSI data link service. The emergence of the metropolitan area network (MAN) standard as an intermediate support for broadband services and the similarities between the DQDB MAC and the AAL type 3/4 in its connectionless mode are discussed     

一种基于GEO卫星网络的IP组网方案的设计及仿真

当前,大部分支持IP的卫星系统只是提供了一个连接地面路由器的物理通道,难以满足带宽接入、多媒体服务以及星地网络一体化等新的需求.为此,提出了一个分组传输和交换均基于IP的GEO卫星系统,采用三层路由交换的组网方案,实现了同一交换域内用户信息的链路层快速转发,以及不同交换域间用户IP信息的网络层路由交换处理.最后,研究了最简单的RIP路由协议在此GEO卫星网络中的适应性,利用OPNET仿真软件对其进行了建模仿真及结果分析.     

TIE Breaking: Tunable Interdomain Egress Selection

In a large backbone network, the routers often have multiple egress points they could use to direct traffic toward an external destination. Today's routers select the ldquoclosestrdquo egress point, based on the intradomain routing configuration, in a practice known as early-exit or hot-potato routing. In this paper, we argue that hot-potato routing is restrictive, disruptive, and convoluted and propose an alternative called TIE (Tunable Interdomain Egress selection). TIE is a flexible mechanism that allows routers to select the egress point for each destination prefix based on both the intradomain topology and the goals of the network administrators. In fact, TIE is designed from the start with optimization in mind, to satisfy diverse requirements for traffic engineering and network robustness. We present two example optimization problems that use integer-programming and multicommodity-flow techniques, respectively, to tune the TIE mechanism to satisfy networkwide objectives. Experiments with traffic, topology, and routing data from two backbone networks demonstrate that our solution is both simple (for the routers) and expressive (for the network administrators).     

IP router architectures: an overview

In the emerging environment of high performance IP networks, it is expected that local and campus area backbones, enterprise networks, and internet service providers (ISPs) will use multigigabit and terabit networking technologies where IP routers will be used not only to interconnect backbone segments but also to act as points of attachments to high performance wide area links. Special attention must be given to new powerful architectures for routers in order to play that demanding role. In this paper, we identify important trends in router design and outline some design issues facing the next generation of routers. It is also observed that the achievement of high throughput IP routers is possible if the critical tasks are identified and special purpose modules are properly tailored to perform them. Copyright © 2001 John Wiley & Sons, Ltd.