层网络管理系统间关系的研究

根据传送网的分层和分割模型,研究了传送网中各层网络管理系统间的关系,包括不同类型层网络的管理系统间和同一类型层网络的多个管理系统间的关系及其接口,并将研究的结果应用到ATM传送网的管理中。     

ITU-T有关EOT功能架构的标准与关键技术

本文根据最新的ITU-T研究进展,介绍、分析和总结了有关传送网承载以太网的传送功能架构,包括传送网分层网络模型的描述;以太网的分层结构与各层特征信息的详细描述;以太网的OTN/ETH等各类适配功能的分析、总结,网络拓扑结构的简要分析,以及相关标准的历史进程介绍.     

光传送网络可靠性与安全性分析

文章概述了光传送网络技术的发展趋势,分析了影响光传送网可靠性和安全性的主要因素,并从传输设备到整个网络系统,运用层层推理的方法,基于常见的网络模型详细描述了传送网络可用率的计算过程。文章还就如何增强光传送网可靠性和安全性,描述了运用保护和恢复这两种机制在提高传送网可靠性中的重要意义。最后总结了不同因素对传送网可用性影响的敏感性,从而概括了传送网上实现差异化服务的思路。     

下一代传送网融合趋势及演进路线展望

下一代传送网是为了适应IP网络发展而逐步演进的。从网络层次来看，下一代传送网包括接入传送网和核心传送网。从技术体制来看，下一代传送网包括分组传送网和大容量的光传送网，并且无论是分组传送网还是大容量的光传送网，都向着更高速率、更可靠的生存性、更高效的性能、更灵活的控制和管理能力方向发展。下一代传送网的网络架构和演进如图1所示。     

光传送网引入SDN的方案研究

近年来传送网技术发展迅速,分组传送网(PTN)技术、光传送网技术(OTN)相继部署,传送网从原来单一技术的网络发展到目前多种技术网络的融合组网,并且随着网络规模也不断扩大,网络变得越来越复杂.如此大规模的网络其管理和互操作性成为光网络发展的一大难题,不同厂家设备网络、不同域之间电路调度变得十分复杂且代价昂贵.SDN技术为解决该问题提供了很好的途经,本文就目前软件定义光传送网(T-SDN)技术相关标准化进程进行梳理,并对光传送网引入SDN的方案进行研究.     

面向5G的城域传送网规划方法及模型研究

本文面向5G城域传送网网络规划,重点针对PTN/SPN系统提出了一种网络规划方法及模型,对城域传送网网络规划有一定的参考意义。     

基于ASON技术的传送网规划和设计

简要介绍了传送网的演进方向，着重探讨了自动交换光网络（ASON）体制下传送网规划设计中涉及的网络模型、生存性模型、路由策略、可靠性模型、成本模型和成本规划算法等问题。     

城域以太网分层网络模型及若干问题的思考

介绍了城域以太网的网络参考模型和分层网络模型。总结了城域以太网的关键元件，提出对分层网络模型的优缺点、城域以太网的体系结构与下一代网络以及传送网承载的以太网（EOT）的关系等相关问题的思考。     

SDN在传送网络的引入与应用分析

认为软件定义网络(SDN)引入传送网可以较为显著地提升资源利用、运维管理等能力,在基站业务、集客业务、家宽业务、光缆网络等应用场景中可通过软件定义网络+分组传送网(SDN+PTN)、软件定义网络+分组传送网+光传送网(SDN+OTN)、软件定义网络+分组传送网+光传送网+无源光网络(SDN+PON)、智能光配线网络(ODN)等实现网络与SDN的结合,实现业务的灵活调度、资源利用率的有效提升、全局性的资源配置。针对每张网络的特点和技术成熟度,对传送网引入SDN的路径进行了分析,尤其针对SPTN(即SDN+PTN)的网络结构和技术要求展开了分析,并对试点情况进行了介绍。最后,对比了SDN引入前后网管的组织架构,并提出SDN引入后各层功能的变化。     

PTN网络删探讨

随着各种电信业务的IP化,分组传送网（PTN）将逐渐替代传统传送网。分组传送网以IP技术为基础,并融合了传统传送网的优点,是一个全新的网络。对分组传送网的技术进行了分析,并根据其技术特点,从网络结构、组网方式、业务等多方面进行规划,对分组传送网的建设提出了建议。     

无连接传送网的管理信息模型

介绍了面向连接和无连接传送技术特性的异同,概括了无连接传送网在功能抽象方面的特性;比较了无连接与面向连接传送网的功能体系结构;介绍了流的概念和特性;并在此基础上采用UML与文本描述结合的方式,从管理对象的行为、属性、操作、通知、以及管理对象的关系等方面定义了一个与协议无关的通用的无连接传送网的管理信息模型。     

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.     

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。     

The sink tree paradigm: connectionless traffic support on ATM LAN's

Asynchronous transfer mode (ATM) is a connection-oriented technology in which all communication is based on virtual connections established prior to the transfer of data. It is expected that the bulk of traffic carried by the ATM network will be data traffic, e.g., local area network (LAN) internetwork traffic. Hence, a major issue regarding ATM is the support for connectionless (datagram) traffic. A scheme for the efficient support for connectionless traffic in ATM LANs based on trees of virtual connections is proposed. In this scheme, a sink tree is built for every switch in the LAN. Each tree provides an efficient means of routing connectionless traffic from any switch in the network to the sink switch (root) of the tree. The sink tree solution may also be used to broadcast connectionless messages in the reverse direction. The trees can easily be updated to adapt to topological changes or congestion in the network. A protocol for refreshing the tree structure using the ATM switch routing tables is described. An adaptive rate control solution, in conjunction with fast back pressure at the ATM layer, is presented. It is shown that this scheme achieves high utilization of available bandwidth for connectionless traffic, has low cell loss probability, and small overhead     

Architectural issues of ATM based connectionless overlay network

Connectionless service such as SMDS, or its European equivalent CBDS, can be provided by an ATM network by building a separate connectionless overlay network (CLON) on top of the ATM bearer service. A CLON is composed of a number of connectionless servers, CLSs, which provide the routing function, connected by semipermanent virtual paths (VPs). In this paper, architectural issues related to the design of a CLON are studied. In particular, we address the question of the optimal number of CLSs and their interconnection topology, assuming the underlying ATM network and the mean connectionless traffic load are known. The objective of the design process is to meet given design criteria with minimum costs. The QoS requirements of the SMDS/CBDS service are briefly reviewed and a simple cost model for the CLON network is given. The dimensioning of the logical links is also considered. Then the design process to find the optimal solution for the whole network is outlined. A simplified procedure was applied in numerical studies of the topological optimization. In order to find the general dependence of the optimal number of CLSs on the size of the network and other network parameters, the optimization procedure was applied to a large number of sample ATM networks, generated by an algorithm which is briefly described. Results from these studies are presented and discussed.     

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     

PTN技术与IP化移动回传网

融合了分组技术及同步数字体系（SDH）技术优势的分组传送网（PTN）技术以分组交换为核心,先天具备高效统计复用能力,更适应分组业务的高效传输。同时其类似SDH的强大运行维护管理（OAM）及电信级保护能力保障了移动回传业务的高效管理及传输质量。基于多协议标签交换传送应用（MPLS-TP）技术的分组传送网在多协议标记交换（MPLS）体系基础上去除了倒数第二跳（PHP）、标签合并及等价多路径（ECMP）等无连接特性,并在OAM、保护及同步技术方面做了相应增强,更适合承载IP化后的移动回传业务及大客户业务。PTN与原有多业务传送平台（MSTP）、城域以太网及IPoverWDM/OTN网络有机配合,合理分工,将共同服务于全IP时代的电信业务。     

B-ISDN中的无连接业务

以ATM交换为基础的B-ISDN提供高速、面向连接、分组长度固定的信元交换.当代PC和高速LAN的发展需要面向连接的ATM网络传输无连接业务.本文重点介绍ATM网络中无连接业务的分类、协议结构和具体实现形式.