Carriers''''carriers结构的BGP/MPLS VPN解决方案

Carriers＇carriers的BGP/MPLS VPN是一种递归嵌套的VPN网络结构.在分析了现有IPv4网络中其实现方法与不足的基础上,利用BGP的权能属性及多协议扩展属性,提出了一种在IPv4/v6混合网络中,基于跨域Carriers＇carriers结构的BGP/MPLS VPN解决方案.该方案以在核心骨干网及VPN承载网络中增设路由反射器为思路,能够很好地解决各级VPN的路由学习及业务流转发.     

智能光网中的联合路由

在IP/MPLS智能光网络中的LSP路由分为独立路由和联合路由两类。由于综合考虑了光层和IP层的可用资源信息和拓扑信息,联合路由能够提供比独立路由方案更高的资源利用率。文中提出了联合路由算法的设计目标,综述了联合路由算法的研究现状,并给出了下一步的研究方向。     

SR软件路由器的设计与实现

分段路由(segment routing,SR)是近几年IETF提出的一种路由机制,其目的是使IP/MPLS网络面向服务并且更高效.SR减少现有MPLS网络控制平面复杂的协议(LDP/RSVP-TE),并实现流量工程等机制.与基于RSVP的显式路径中隧道中间节点维护报文流的状态不同,基于SR的显式路径只在入口边界路由器中维护报文流的状态,从而提高了网络的可扩展性,因此SR对于下一代互联网具有重要的研究意义.对SR的实现机制进行了研究,利用软件路由平台Click,对基于PCE架构的SR控制平面子系统和基于MPLS的SR数据平面子系统的各个模块进行实现,并在实际中进行部署,以验证SR软件路由器的可行性.     

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。     

对IP QoS问题的研究及一种MPLS Diff-serv解决方案（下）

MPLS的设计实际上就是面向区别业务模型的。MPLS技术的基本原理是将网络层的路由机制与链路层的标记交换机制结合在一起。在MPLS网络域的入口处,入口LSR依据转发等价类的概念,给每一个分组分配一个固定长度的标记。随后,在MPLS区域的内部,各网络节点将根据每个分组上所携带的标记对它们进行转发,而不必再去关心各个分组原来的头标。     

一种自路由群组交换结构的无缓存能耗优化模型

考虑到缓存是路由交换通信设备能耗的主要来源,该文从交换网络无缓存节能的构想出发,提出了一种自路由群组交换结构的无缓存能耗优化模型。该模型采用G倍统计线复用路由单元和Banyan类交换互连建立群组交换结构,在满足业务对阻塞率和时延性能要求的基础上,采用无内部缓存、路由单元输入输出端口数扩展和级间互连线优化设计来达到节能的目的。相同网络性能下,缓存能耗和结构能耗的量化比较表明该无缓存结构能耗小。仿真实验结果证明:结构参数G越大,网络级数k越小,路由单元能耗越小,在Banyan类交换互连结构中,分治(Divide-and-Conquer, DC)互连方式的级连线能耗最小。     

智能光网中的联合路由

在IP／MPLS智能光网络中的LSP路由分为独立路由和联合路由两类。由于综合考虑了光层和IP层的可用资源信息和拓扑信息，联合路由能够提供比独立路由方案更高的资源利用率。文中提出了联合路由算法的设计目标，综述了联合路由算法的研究现状，并给出了下一步的研究方向。     

基于ATM的MPLS流量工程研究

研究了基于ATM的MPLS,重点研究和分析了具体实现MPLS流量工程的ATM流控措施、使用约束路由的标记分发协议、路由协议,为MPLS流量工程的具体实施提供了参考。同时研究了MPLS多协议标记交换技术融合IP路由技术、ATM的QoS（Quality of Service）及交换技术,使得流量工程模式可以部署在基于IP的网络,其中包括ATM网上承载IP业务的模式。     

一种基于网络最大流的MPLS流量工程动态路由算法

在MPLS技术基础上提出了一种基于网络最大流的有带宽保证的动态路由算法-MBGRA,该算法通过链路对结点对之间的网络最大流的贡献程度以及链路的带宽利用率来定义链路权重,并且链路对将来建立新的标签交换路径的影响一同考虑.     

基于网络处理器路由转发的微码设计技术研究

针对网络技术和通信技术的飞速发展对路由器等网络核心设备的带宽和业务多样性提出了全新要求的问题,提出了一种基于网络处理器的多协议路由转发设计方案。该方案采用一款异构的网络处理器,结合IPv4、IPv6和MPLS(Muxtiprotocol Label Switch)路由转发规则,将路由转发任务合理分解到该网络处理器的四类微引擎上。实验结果证明,此实现方法能同时实现支持以上三种协议的路由转发应用,且能获得10Gbps线速级别的转发效率,满足人们对接入层面的路由转发需求。     

QoS routing granularity in MPLS networks

This study investigates how constraint-based routing decision granularity significantly affects the scalability and blocking performance of QoS routing in an MPLS network. Coarse granularity, such as per-destination, has lower storage and computational overheads but is only suitable for best effort traffic. On the other hand, fine granularity, such as per-flow, provides lower blocking probability for bandwidth requests, but requires a huge number of states and high computational cost. To achieve cost-effective scalability, this study proposes using hybrid granularity schemes. The overflowed cache of the per-pair/flow scheme adds a per-pair cache and a per-flow cache as the routing cache, and performs well in blocking probability. The per-pair/class scheme groups the flows into several paths using routing marks, thus allowing packets to be label-forwarded with a bounded cache     

An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks

This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated.     

Protection approaches for dynamic traffic in IP/MPLS-over-WDM networks

Due to the explosive growth of data-related traffic driven by the Internet, network reliability becomes an important issue. We investigate various protection approaches to handle failures for dynamic traffic demands in IP/MPLS-over-WDM networks. An LSP can be protected at either the IP/MPLS layer or the optical layer. In IP/MPLS layer protection, an LSP is protected by providing a link-disjoint backup LSP between its end nodes. In optical layer protection, an LSP is protected by the backup lightpath of each lightpath traversed by the LSP. We present two integrated routing algorithms: hop-based integrated routing algorithm and bandwidth-based integrated routing algorithm (BIRA) to set up the restorable bandwidth-guaranteed paths efficiently. Then we present a multilayer protection scheme for multiclass traffic in such networks. This scheme takes into account the different QoS and recovery requirements of the traffic to provide protection capability either at the MPLS layer or at the optical layer in a cost-effective manner. We use the connection blocking probability and number of optical-electrical-optical conversions as performance metrics to compare various protection approaches.     

内容中心网络中基于温度场的路由算法

内容中心网络（content-centric networking,CCN）作为一种全新的网络体系结构,对路由算法的设计提出了许多新的挑战。针对CCN的特点,提出了一种基于温度场的路由（temperature field based routing,TFBR）算法,将物理学中稳态温度场的概念引入CCN,并采用有限元法求解稳态温度场,形成路由转发决策。仿真实验表明,TFBR 算法能够充分利用CCN 的路由节点缓存功能,在降低网络平均时延性能的同时,提高了CCN 的负载均衡性能。     

On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code (OOC)/Wavelength Label

To accommodate the explosive packet-based data traffic in WDM networks, intelligent optical routing and switching are required in optical transport networks. Optical multiprotocol label switching networks emerged to meet this demand. In this paper, different schemes for implementing an OMPLS network are introduced. An optical MPLS network using OOC/wavelengths as labels is proposed. Based on an all-optical code converter, the architecture of the optical core router is demonstrated. The fundamental limits on scalability of the proposed core router, namely the label capacity, and the blocking probability of the label switched path setup are investigated, and closed-form solutions are derived.     

面向运营的MPLS VPN网络设计研究

随着MPLS技术应用的普及,本文面向运营需要探讨MPLSVPN网络设计问题,首先对MPLSVPN技术实现模式进行对比分析,阐述BGP/MPLSVPN和L2MPLSVPN两种方式的技术特点,在此基础上,提出MPLSVPN路由及相关配置方案,并分别从链路连接、设备选择等方面阐述MPLSVPN网络部署方案,为MPLSVPN网络设计提供借鉴和参考。     

Strategy for Dynamic Routing and Grooming of Data Flows into Lightpaths in New Generation Network Based on the GMPLS Paradigm

This paper reports on a novel strategy and related algorithm for realizing dynamic routing and grooming into wavelengths of data flows (label switched paths, LSPs) in new generation optical networks based on generalized MPLS (GMPLS). The method allows arbitrary granularities of LSPs. The new generation network is modeled as a multi-layer network consisting of an IP/MPLS layer and an optical layer. In particular, the proposed solution adopts a dynamic routing algorithm based on the Dijkstra algorithm, that makes use of a weight system, integrated with a suitable method for grooming LSPs into wavelengths based on the packing criterion, thus harmonizing the features of MPLS packet flows whose bandwidth vary in a continuous range of values, with the optical world, where the wavelength bandwidth ranges according to discrete values. The weight system is based on the concepts of least resistance routing that allows to evenly distribute the traffic at the MPLS layer, while packing improves the use of optical resources by favoring more filled wavelengths with respect to the emptier ones. To assess the validity of the proposed solution a simulation model has been realized. The results obtained by simulation show that the packing criterion allows reducing the refused bandwidth from two down to about four times, for a network load of 70% and 55%, respectively, when compared with the alternative method named spreading. The dependence of the proposed solution on bandwidth granularity has been also investigated. Moreover, in order to demonstrate the superior performance of the proposed routing solution, a comparison between the proposed strategy with relevant solutions known in the literature, based on either a single or multi-layer approach, is also reported. In order to perform the comparison, all the reference routing solutions that have been considered adopt the packing method for LSP grooming into the lightpaths. The results show that our solution outperforms the others in terms of amount of traffic that can be on-line accommodated. For instance, assuming a blocking probability of 10^–3, the proposed solution is able to further reduce the refused bandwidth of the best routing algorithm considered in the analysis by a factor of three times, thanks to the knowledge of optical resource availability.     

Evolution of multiprotocol label switching

Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates     

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.