无连接传送网的分层模型与网络特性

文章借助ITU T的网络模型描述方法和有关传送网承载以太网建议的思想,介绍了无连接传送网的有关概念,并着重对其分层模型与网络特性进行了分析和总结。     

分组传送网操作、管理和维护技术

为了适应面向连接的电信级业务传送,电信级操作、管理、维护（OAM）和保护,业务感知需求等,需要采用面向连接的分组传送技术。分组传送网（PEN）技术包括传送多协议标签交换（T—MPLS）和运营商骨干传送（PBT）。T—MPLS对MPLS技术进行了简化和改造,去掉了与传送无关的转发处理和无连接特性,并增加了传送层的网络模型、保护倒换和OAM功能;PBT技术着重加强了OAM和保护方面的特性,增加了TDM业务仿真和时钟功能,增强了多业务支持能力,关闭了传统以太网的地址学习、地址厂播以及生成树协议（STP）的功能。T—MPLS和PBT均很好地满足了分组传送的需求,T—MPLS相比PBT,OAM功能更完善。     

面向未来的光传送网（OTN）技术

阐述了光传送网的特征、功能和分层、连接、生存技术、网络管理和连接监视技术，并对实现光传送网的关键技术进行了简要的介绍。     

面向未来的光传送网（OTN）技术

阐述了光传送网的特征、功能和分层、连接、生存技术、网络管理和连接监视技术，并对实现光传送网的关键技术进行了简要的介绍。     

多粒度光网络传送平面管理信息模型的研究与设计

利用信息建模的方法,在总结基本传送网管理资源的基础上,分析了多粒度光网络传送平面各粒度层面以及多粒度连接的原子功能点,并对传送平面管理对象进行了分类和具体设计。     

T-MPLS网络的OAM监测处理

T-MPLS是面向连接的技术,是MPLS在传送网中的应用,在MPLS的基础上增加了具有传送风格的面向连接的端到端的OAM功能.主要介绍了T-MPLS层网络中OAM的定义,OAM包的数据格式及OAM故障管理功能的监测处理方式.     

光网络的发展与展望

首先简要介绍了光网络的基本概念,然后阐述了光传送网的主要优势,接下来分别论述了IP业务量对传送网结构的影响、从点到点WDM向光联网演进的必要性和演进的步骤以及全光光交叉连接设备的现状与发展,最后阐述了光传送网络向ASON演进的必然趋势.     

T-MPLS分组传送技术

T-MPLS是一种基于MPLS的面向连接的分组传送技术,它为下一代传送网提供了一种统一的全业务解决方案.本文首先对T-MPLS的国际标准化进程进行了介绍,然后根据ITU-T和IETF相关建议和国内外的研究趋势,对这种新兴的分组传送技术——T-MPLS的体系结构、信号适配与传输、OAM和生存性方面取得的成果和存在的问题进行了阐述.     

面向分组应用的城域传送光网络规划研究

首先介绍了以分组业务为主的需求对城域传送网带来的影响,对目前主流的IPoverSDH/WDM、面向连接的分组传送技术作了介绍;在此基础上重点研究了面向分组的城域传送光网络尤其是接入部分的系统架构和演进,对城域传送网络的发展提出了设想.     

光交叉连接设备（OXC）的基本功能及组成原理

从光传送网当前所面临的问题出发,指出光交叉连接设备(OXC)是解决光传送网络节点问题的有效方法。重点讨论了OXC的基本功能及工作原理,比较详细地介绍了OXC主要功能模块的功能及原理。     

Transmitting time‐critical data over heterogeneous subnetworks using standardized protocols

Current communication networks consist of subnetworks of different types. Therefore a common network protocol has to be used for the transmission of data in such a heterogeneous network. Since some time the requirement of mobility in communication networks is showing up. For that reason wireless networks are playing an increasing role as subnetworks. On the other hand there is the need for multiplexed transmission of time-critical and non time-critical (normal) data within a heterogeneous network. In this paper we discuss the problem of multiplexed transmission of time-critical and of non time-critical data over a wireless type subnetwork using a common standardized network protocol. Many of the available wireless subnetworks are of low or medium transmission speed and guarantee a fixed transmission bandwidth at the access point. We describe a mechanism to transmit time-critical data in such a type of subnetwork using a connectionless transport and a connectionless network protocol. The concurrent transmission of non time-critical data using a connection oriented transport and the same connectionless network protocol is assumed to be of lower priority; it is scheduled in a way to fill the remaining capacity, which has not been reserved for the transmission of time-critical data. In our discussion we concentrate on the standardized ISO/OSI protocools CLNP as connectionless network protocol, CLTP as connectionless transport protocol and TP4 as connection oriented transport protocol. We propose a header compression protocol and a fragmentation protocol for use on low bandwidth subnetworks. This revised version was published online in June 2006 with corrections to the Cover Date.     

A simple and efficient routing protocol for the UMTSA Access network

This paper presents a simple network layer protocol that integrates routing and connectionless transfer of data in a wireless environment. The protocol is specifically geared towards supporting transfer of signalling in mobile networks based on a rooted tree topology. Exploiting the special characteristics of such a topology allows the specification of a very simple and processing efficient routing function. Using the routing function, a connectionless message transport service is implemented. The connectionless transport service is comparable to that of typical network layer protocols of existing data networks. The protocol has originally been specified to carry signalling messages in the control plane of mobile, cellular systems but has the potential to be used also in other environments.     

Connectionless service for public ATM networks

The interconnection of connectionless LANs and MANs over a connection-oriented B-ISDN presents a dilemma with regard to efficient interoperability. In order to provide solutions to this dilemma, there have been many techniques proposed. We describe and evaluate the architectural and conceptual alternatives available for the implementation of a connectionless service for public ATM networks. We also suggest a scheme through which best-effort connectionless service may be provided in public ATM networks using connectionless servers and hop-by-hop flow control. There is as yet no consensus on issues such as bandwidth management, address resolution, connectionless server forwarding modes, or connectionless server topology, and therefore much of the area remains open for research. These research issues must be addressed, however, in order to realize the interoperability, and thereby the acceptance, of ATM     

An advanced channel access scheme for integrated multimediaservices with various bit rates in CDMA networks

For efficient code sharing among users, a wireless medium access control (MAC) protocol for CDMA networks is proposed, which supports connection-oriented, as well as connectionless, services and provides the various bit rates needed for the integrated multimedia services. The proposed MAC protocol allows mobile terminals to use multiple slots and spreading codes based on contention and reservation. Optimum frequency resources are allocated to the connection-oriented and connectionless services with various bit rates. Waiting and response times in the first contention are reduced, and the overall mean delay time is typically minimized in the case of connectionless bulky traffic     

基于无连接传输模式的选路算法

文中借鉴通信中面向无连接传输模式的思路,构建了一个求解最佳路径的虚拟网络,使信息在虚拟网络中交互,自动探索最佳路径。并详细描述了虚拟网络的结构,给出了通信网和公交网两个求解实例。最后,通过计算复杂度分析,用文中所述算法与通用的Dijkstra算法进行比较,验证算法的计算速度。     

Frame transport systems

The evolution of T1-based private networks is reviewed. It is shown that as a result of bursty data, voice/data segregation, and processor advances, data networks are becoming packet-based. The need for efficient transport of data, and possibly voice, point to a frame-based system with the possibility of eventually moving to a cell-based system. An architecture for supporting connectionless transport over wide-area networks (WANs) may be needed eventually, but for now the connection mode is sufficient. Since virtually all data transport will be protocol-oriented, the need for efficiency at high speeds will supersede the need for the network to guarantee delivery. It is shown that frame relay meets these criteria. As a frame-based, connection-oriented fast-packet technology, it provides the needed functions for emerging corporate networks     

Data communications using ATM: architectures, protocols, andresource management

The introduction of ATM is being propelled by the need for fast data communications in public and private networks. What is needed is a clear picture of protocol architectures and traffic characteristics of the various applications to be supported both now and in the future. The authors discuss ATM network architectures with special focus on the support of connectionless LAN interconnection and show which benefits can be obtained from the introduction of a connectionless server in an ATM network. They outline issues related to the use of existing protocols when ATM networks are introduced and show which protocol complexities have to be handled by gateways and servers, again using the example of connectionless LAN interconnection. Having presented network and protocol architectures the issue of data communication in ATM, resource allocation, is treated     

A/I Net: a network that integrates ATM and IP

Future networks need both connectionless and connection-oriented services. IP and ATM are major examples of the two types. Connectionless IP is more efficient for browsing, e-mail, and other non-real-time services; but for services demanding quality and real-time delivery, connection-oriented ATM is a much better candidate. Given the popularity of the Internet and the established status of ATM as the broadband transport standard, it is unlikely that one can replace the other. Therefore, the challenge we face lies in finding an efficient way to integrate the two. This article describes a research project reflecting this trend. The project aims at efficient integration of the two to eliminate the deficiencies of a standalone ATM or IP network     

An analysis of TCP processing overhead

The transport layer of the protocol suite, especially in connectionless protocols, has considerable functionality and is typically executed in software by the host processor at the end points of the network. It is thus considered a likely source of processing overhead. However, a preliminary examination has suggested to the authors that other aspects of networking may be a more serious source of overhead. To test this proposition, a detailed study was made of the Transmission Control Protocol (TCP), the transport protocol from the Internet protocol suite. In this set of protocols, the functions of detecting and recovering lost or corrupted packets, flow control, and multiplexing are performed at the transport level. The results of that study are presented. It is concluded that TCP is in fact not the source of the overhead often observed in packet processing, and that it could support very high speeds if properly implemented