多协议标签交换网络的OAM机制研究与实现

多协议标签交换技术MPLS是可扩展的下一代网络的关键承载技术,为了保障其传输数据质量不依赖于其他服务层,需为其提供独立的OAM机制。文中基于Y.1711协议分析MPLSOAM的基本功能及实现。重点研究MPLSOAM报文传输功能,通过在系统中添加OAM报文转发模块实现,从而对MPLS网络数据平面缺陷的进行检测及定位,及时通知入节点进行保护倒换以维护网络高可用性、降低运营成本。     

基于IP源路由的高速路由协议研究

带宽业务与多领域拓展性是新一代互联网的重要特点,这对网络路由器性能、服务能力提出了更高的要求。文中提出一种基于IP源路由机制的高速路由协议SR-HRP（Source Routing High Router Protocol）,区别于传统的源路由协议,SR—HRP源节点独立探索、维护到达目标节点的有效路径,在报丈传输时为路由器提供基于端口的转发信息,避免路由器因查询庞大路由表消耗的时间与资源。仿真结果表明,SR-HRP能够有效提高网络传输效率。     

MPLS网络中的QoS路由粒度研究

研究了基于约束的路由决策粒度对MPLS网络中QoS路由可靠性和阻塞性能的影响。为实现成本效益的可测量性,这里在现有粒度方案的基础上,提出了使用混合粒度方案：每对/流粒度方案和每对/类粒度方案。有每对/流粒度的每对流方案增加了P缓存和O缓存作为路由缓冲,完成了低阻塞率。有每对/类粒度的每对类方案将流汇聚到几条路由路径,从而允许数据包在有限的缓存规模内被标签转发。仿真结果表明,混合粒度方案减少了路由缓存规模,适合于MPLS网络。     

Ad Hoc网络先应式路由维护机制的优化模型研究

Ad Hoc网络先应式路由算法(Proactive Routing Algorithm)具有寻由时延小,拓扑维护及时的优点,适合在网络负载较大的环境下高效运行.本文针对路由维护机制,以减少协议开销和寻由错误报文为目标,提出了基于Ad Hoc网络的先应式路由维护机制优化模型.通过对优化模型的相关参数讨论,得出如下结论:1.先应式路由协议的最优更新时间周期具有"逆向稳定性";2.节点数目n与更新系数h有比例关系n→h^3/2.通过模型求解和仿真结果相比较,验证了模型的正确性.优化模型的研究为先应式路由算法更新机制和算法的可扩展性支持提供了理论依据.     

IP网络与数字付费电视未来发展试想

基于MPLS/VPN的internet组播技术对数字付费电视发展:MPLS/VPN是基于MPLS技术的IP VPN,在网络交换机和路由设备用应MPLS技术,简化路由的路径选择方式, 利用结合传统路由技术的标签交换实现因特网上IP虚拟专用网络组播技术,是MPLS/VPN对于实现电视视频数据包在IP 网络上传输的QOS保证。     

GMPLS的动态路由机制研究

GMPLS由MPLS演进而来,它是MPLS向光层扩展的必然产物,路由技术是GMPLS的一项关键技术。这里简要回顾了MPLS技术,在此基础上对GMPLS中与路由相关的关键技术做了介绍,讨论GMPLS中现有的路由选择策略,论述基于GMPLS支持的对等网络模型对一种联合的网络结构及其控制平面的结构,最后提出基于GMPLS的网络中一种有QoS保证的动态路由机制。     

基于INT感知的5G核心网用户面流量调度系统

为解决5G移动数据流量激增和新型网络应用不断涌现给网络运维造成巨大压力的问题,设计并实现一个面向5G核心网用户面的流量调度系统,包含网络状态信息感知子系统和路由决策子系统。在网络状态信息感知子系统中,传统带内网络遥测方法带宽开销高,而且不是专门为无线网络系统设计的,此外,在5G核心网中应用带内网络遥测还面临测量精度不高、QoS无法保障等挑战。为此,提出了基于带内网络遥测的5G核心网用户面状态信息感知方案,将遥测信息插入GTP-U报文的扩展头部,实时检测UPF状态信息,实现网络状态动态随路测量。路由决策子系统实现了基于改进蚁群算法的流量调度算法,利用感知到的网络状态信息升级信息素函数更新方式,完成基于实时网络状态的路由决策。实际部署测试结果表明,网络状态信息感知子系统能正常感知网络信息,而且所做路由决策在时延、吞吐量和丢包率方面优于传统路由算法。     

一种基于BGP/MPLS的VPN设计与实现

BGP/MPLS VPN具有良好的可扩展性和灵活性,是目前发展最为迅速的VPN技术之一。首先分析了BGP/MPLS技术的VPN模型,对BGP/MPLS VPN的基本原理进行介绍,然后在基于ATM框架下最大限度地兼顾原有控制平面,在上层控制平面少量修改的情况下,有效地利用内部虚拟 MAC地址信息将控制平面和转发平面有机联系起来,在不支持MPLS标签交换的交换芯片上实现VPN报文转发,并提出了一套完整的设计和实现方案。     

MPLS VPN汇聚层和核心层网络的冗余方案设计与实现

MPLS VPN是一种基于MPLS技术的IP-VPN,是在网络路由和交换设备上应用MPLS技术,简化核心路由器的路由选择方式,利用结合传统路由技术的标记交换实现的IP虚拟专用网络（IP VPN）,可用来构造宽带的Intranet、Extranet,满足多种灵活的业务需求。本文根据MPLS VPN协议集的功能特性和技术原理。针对网络中存在单点故障的可能性,从网络的汇聚层与网络的核心层进行理论分析和采用实验的方法来论证整个网络的冗余性,并对关键技术加以分析和实现。     

论新时期OSPF路由协议故障分析

OSPF,是一种开放式的,以最短路径优先为连接协议原则的内部网关协议.在单一自治系统的内部决策路由环境里,连接状态路由协议的实现可以运作于整个的系统内部.根据OSPF的工作机制,对于开放最短路由优先协议的支持,结合IP子网和外部路由信息的引入,可以提供很好的发送和信息接收方式.支持OSPF协议的路由器维护者描述自制系统拓扑结构的数据库,路由器往往是描述本地状态信息,在多址访问的网络过程中,网络链路状态的广播必须要使用指定的路由器传播,如果区域内路由器的连接信号发生故障,那么就可能建立不成功,无法交换信息.本文希望论述基于OSPF协议的路由链接故障产生原因,并且简述一般的解决办法.     

RATES: a server for MPLS traffic engineering

It has been suggested that one of the most significant reasons for multiprotocol label switching (MPLS) network deployment is network traffic engineering. The goal of traffic engineering is to make the best use of the network infrastructure, and this is facilitates by the explicit routing feature of MPLS, which allows many of the shortcomings associated with current IP routing schemes to be addressed. This article describes a software system called Routing and Traffic Engineering Server (RATES) developed for MPLS traffic engineering. It also describes some new routing ideas incorporated in RATES for MPLS explicit path selection. The RATES implementation consists of a policy and flow database, a browser-based interface for policy definition and entering resource provisioning requests, and a Common Open Policy Service protocol server-client implementation for communicating paths and resource information to edge routers. RATES also uses the OSPF topology database for dynamically obtaining link state information. RATES can set up bandwidth-guaranteed label-switched (LSPs) between specified ingress-egress pairs. The path selection for LSPs is on a new minimum-interference routing algorithm aimed at making the best use of network infrastructure in an online environment where LSP requests arrive one by one with no a priori information about future requests. Although developed for an MPLS application, the RATES implementation has many similarities in components to an intradomain differentiated services bandwidth broker     

Demonstration of the highly reliable Hikari router network based on a newly developed disjoint path selection scheme

Integration of multiprotocol label switching functions and multiprotocol lambda switching functions can enhance the throughput of IP networks and remove bottlenecks that are derived from electrical packet processing. To enhance the packet forwarding capability, NTT proposed a photonic MPLS concept that includes MP/spl lambda/S, and demonstrated IP, MPLS, and photonic MPLS integrated router systems called the photonic MPLS router. This router system is now called the Hikari router. The word Hikari is Japanese meaning beam, light, lightwave, optical, photonic, and sunshine. The amount of IP data traffic has grown remarkably. Massive IP routers and flexible route control mechanisms are now required to cope with the increased amount of traffic. The Hikari router can offer two solutions utilizing photonic switching technologies, and photonic network operation and management technologies. The first solution is utilizing photonic switching technologies realized using optical-switch-based crossconnect systems. The other solution is realized using the MPLS and MP/spl lambda/S signaling protocol and photonic network protection functions. In this article we report on the implementation of the Hikari router systems, propose a newly developed disjoint path selection scheme for generalized MPLS networks with shared risk link group constraints, and demonstrate the signaling protocol and network protection functions. The demonstration system achieves a distributed optical path set-up/tear-down protocol with an extended constraint-based routing label distribution protocol. Fast self-healing through automatic protection switching and a new restoration scheme are also implemented. These functions are successfully implemented, and the performance is verified on a demonstration network. The protection switching scheme achieves protection in less than 20 ms, and the optical path restoration scheme achieves restoration in less than 500 ms.     

A novel IP with MPLS over WDM-based broad-band wavelength switchedIP network

This paper presents a new technology for constructing IP over photonic systems. An IP with multiprotocol label switching (MPLS) over wavelength division multiplexing (WDM)-based broad-band IP network architecture and protocol is proposed and analyzed in this paper, which supports variable-length IP-like optical packet label switching and optical virtual path routing. This system tries to merge into one layer the functionalities of the wavelength switching, SONET mux/demux, and IP routing, and is sometimes known as the concept of optical MPLS. The label banding, forwarding/switching process, and node architecture of the proposed network are discussed and studied. A unique as well as important function of a lambda/label edge router (LER) is a flow assembly device that can encompass MPLS' forward equivalence classes, label stacking, and label switching path aggregation function. At the same time, a particular function of the core label switching router is wavelength merging. A fiber delay line is used to delay the data stream in order to process the label information and resolve contention. Transmission bit error rate measurements of the baseband data stream and back-to-back is also demonstrated to show its feasibility     

A scalable QoS routing model for diffserv over MPLS networks

In this paper, we present a new Quality of Service (QoS) routing model for Differentiated Services (Diffserv) over Multiprotocol Label Switching (MPLS) networks. We use a pre-established multi-path model in which several MPLS label switching paths (LSPs) are established between each ingress-egress router pair in advance. Ingress routers perform per-request admission control and bulk-type resource reservation based on the resource availability on the associated LSPs. We use a utilization-based dynamic load balancing scheme to increase resource utilization across LSPs. The proposed model increases signaling and state scalability in the network core. It also provides hard QoS guarantees and minimizes admission control time. The experimental results verify the achievements of our model under various network topologies and traffic conditions.     

一种基于跳数和时延的MPLS自适应流量工程算法

提出了一种基于跳数和时延的MPLS自适应流量工程算法，该算法根据LSP的跳数和时延来进行流量分配，从而减少由传统路由算法而引起的网络拥塞，优化网络资源的利用。仿真结果表明，该算法简单易行，性能良好。     

SRv6技术探讨

SR技术通过扩展IGP协议实现segment信息的交互,进而实现基于业务、拓扑等的SR-TE流量工程,基于TI-LFA FRR可保障任意网络拓扑的高可靠性。SR在数据平面支持MPLS和IPv6 2种封装方式,既继承了MPLS技术的优势,又能适应IPv6、SDN等技术的发展,极大地降低了网络协议部署的复杂度。分析了基于IPv6协议的SRv6源路由技术,并探讨了SRv6的组网方案,为未来IPv6-only网络发展演进提供参考。     

基于PNNI的ASON路由协议

通用多协议标签交换(GMPLS )是将多协议标签交换 /流量工程(MPLS-TE )进行光网络扩展,并被广泛接受作为自动交换光网络(ASON )控制面协议的理想选择,然而标准化组织正讨论研究将专用网网间接口( PNNI )协议用于 ASON 控制面的潜力。文中主要通过对 PNNI 的路由分层概念、 PNNI 的路由信息分发机制和 PNNI 的路径选择机制的介绍,给出 PNNI 路由的几个扩展,以适合 ASON 的路由需求。     

Differentiated transmission services and optimization based on two‐dimensional forwarding for Internet traffic in the AS

Two‐dimensional routing (TD routing) implements flexible multipath transmission according to the inherent fields of IP packets. However, it may cause large overhead on routers' control plane and data plane. Focusing on autonomous systems with multiple exits, this paper proposes a differentiated transmission services and optimization based on two‐dimensional forwarding for Internet traffic in the autonomous system (AS) (DOTF). The optimal path from the access router to the border router is calculated by the border router. Then two‐dimensional routing information (TDRI) is advertised hop by hop along the reverse path of the optimal path to establish a TD transmission path. DOTF propagates routing information by extending the open shortest path first (OSPF). It compresses message content and optimizes the TDRI structure. TDRI is only released on the specific paths, which greatly reduces the resource consumption in the routers' control plane and data plane. We also analyze the merging of TD routing and one‐dimensional routing (OD routing), reducing the deployment of TD routing entries (TD‐REs). Our experiments on real routers demonstrate the performance of DOTF. The convergence characteristics of TD routing are also analyzed.     

Using tunneling techniques to realize virtual routers

The evolution of the router architecture has gradually changed from a conventional architecture, which processes all functions on one operating system/processor, to a remote architecture, which can be split into a control plane and a data plane with their respective functions. The control plane is mainly responsible for the operations of the routing/signaling protocols and the data plane is responsible for forwarding the large amount of data packets. Furthermore, the remote architecture facilitates the realization of virtual routers. Virtual routers are created basically by logically splitting a routing processor in the control plane into many virtual routing units that have independent routing tables, use independent protocols, and connect to the external network through different interfaces. A virtual router with a remote architecture is more flexible and efficient than conventional routers; however, it requires an additional communication mechanism between the control plane and the data plane. We propose using existing tunneling techniques to provide a communication mechanism between the control plane and the data plane. Many design and implementation issues on the software architecture and protocol ramification are identified. We discuss solutions to these issues and successfully demonstrate a working virtual router with our proposed solutions.