宽带综合IP网的MPLS技术及其应用

多协议标记交换（MPLS）技术是综合利用网络第二层交换技术的有效性和第三层IP路由的灵活性等优点而产生的多层交换技术。通过在传统的IP包里加入标记，使路由转发依赖于标记，大大地提高IP包的转发速度，同时可使传统IP网络具有服务质量（QoS）能力。现主要分析MPLS体系结构，指出MPLS的一些应用。     

下一代网络--多协议标记交换MPLS思想剖析

多协议标记交换MPLS通过在传统的IP包里加入标记，使原来依赖于IP头标分析的路由转发转变为依赖于标记的转发，这不仅可以大大地提高IP包的转发速度，更可使传统IP网络具有QoS能力。本文深入分析了标记转发的思想．并指出了MPLS实现其优点所用的机制与原理。     

SEAL2: An SDN‐enabled all‐Layer2 packet forwarding network architecture for multitenant datacenter networks

This paper presents the design and development of a new network virtualization scheme to support multitenant datacenter networking (MT‐DCN) based on software‐defined networking (SDN) technologies. Effective multitenancy supports are essential and challenging for datacenter networking designs. In this study, we propose a new network virtualization architecture framework for efficient packet forwarding in MT‐DCN. Traditionally, an internet host uses IP addresses for both host identification and location information, which causes mobile IP problems whenever the host is moved from one IP subnet to another. Unfortunately, virtual machine (VM) mobility is inevitable for cloud computing in datacenters for reasons such as server consolidation and network traffic flow optimization. To solve the problems, we decouple VM identification and location information with two independent values neither by IP addresses. We redefine the semantics of Ethernet MAC address to embed tenant ID information to the MAC address field without violating its original functionality. We also replace traditional Layer2/Layer3 two‐stage routing schemes (MAC/IP) with an all‐Layer2 packet forwarding mechanism that combines MAC addresses (for VM identification and forwarding in local server groups under an edge switch gateway) and multiprotocol label switching (MPLS) labels (for packet transportation between edge switch gateways across the core label switching network connecting all the edge gateways). To accommodate conventional IP packet architecture in a multitenant environment, SDN (OpenFlow) technology is used to handle all this complex network traffics. We verified the design concepts by a simple system prototype in which all the major system components were implemented. Based on the prototype system, we evaluated packet forwarding efficiency under the proposed network architecture and compared it with conventional IP subnet routing approaches. We also evaluated the incurred packet processing overhead caused by each of the packet routing components.     

MPLS支持移动IP技术研究

移动IP是一种在全球Internet上为移动节点提供移动功能的方案。同时,鉴于MPLS是一种基于三层边缘路由、二层核心标签交换的技术,可以较大程度地提高分组的转发速度,业界对扩展MPLS功能使其支持移动性产生了极大的兴趣。文章主要讨论MPLS支持移动IP的技术细节。     

Layer 3 VPN Services over IPv6 Backbone Networks: Requirements, Technology, and Standardization Efforts

Layer 3 virtual private networks (L3VFN) enable organizations to connect geographically dispersed sites to one another across the packet switched network of a service provider. The most popular form of L3VPN is based on BGP/MPLS (border gateway protocol/multiprotocol label switching) technology in which the service provider offers a network-based IP VPN routing and forwarding service to its customers across its own IPv4-based MPLS backbone network. With the deployment of IPv6-based backbone networks underway, there is an emerging requirement to support these same L3VPN services across a native IPv6 backbone network. This introduces a requirement to provide routing and tunneling of IPv6 VPN (and IPv4 VPN) packets across an IPv6 backbone network. Softwires is an Internet Engineering Task Force (IETF) Working Group chartered to address the requirement of providing a generalized, network-based, multi-address family, IP routing and tunneling capability across native IP backbone networks pursuant to IPv6 transitions. Elements of the softwires work can form the basis of an L3VPN over IPv6 solution. After providing a brief overview of how L3VPN works in various topologies, this article presents the requirements for L3VPN services over an IPv6 backbone network and discusses a possible solution set that builds over the softwire technology and related IETF standards. Finally, we outline future directions and how the softwire technology can support new services and improved scalability     

Reliable services in MPLS

MPLS (multiprotocol label switching) is a convergence of various implementations of IP switching using ATM-like “label swapping” to speed up packet forwarding without changes to existing IP routing protocols. An important practical issue is the capability to recover quickly from faults. We examine distributed methods for fast fault recovery using modified label distribution protocol messages. To maintain and verify service continuity, methods are proposed for traffic and performance monitoring     

MPLS的关键技术及其应用

说明MPLS是一种较好的IPOverATM解决方案 ,简要地描述MPLS多协议标记交换的基本原理和MPLS的优势 ,探讨实现MPLS的几个关键技术 ,并介绍基于MPLS的VPN应用。     

Dynamic cache allocation routing strategy of Internet of things satellite node based on traffic prediction

Aiming at the routing problem of low earth orbit (LEO) Internet of things (IoT) satellite systems,a dynamic cache allocation routing strategy based on traffic prediction for IoT satellite nodes was proposed.Firstly,the space-time characteristics of traffic distribution in the LEO coverage area were analyzed,and an end-to-end traffic prediction model was proposed.Then,according to the traffic prediction result,a dynamic cache allocation routing strategy was proposed.The satellite node periodically monitored the traffic load of the inter-satellite link,dynamically allocated the cache resources of each inter-satellite link between the neighboring nodes.The cache allocation process was divided into two phases,initialization and system operation.At the same time,the traffic offload and packet forwarding strategy when the node was congested was proposed.By comparing the queuing delay and the forwarding delay,it was determined whether the data packet needs to be rerouted.The simulation results show that the proposed routing strategy effectively reduces the packet loss rate and average end-to-end delay,and improves the traffic distribution in the whole network.     

MPLS-Linux体系结构及交换路由性能分析

本文详细介绍了MPLS-Linux的体系结构、核心数据结构、标签交换过程和QoS运行等实现技术，通过对MPLS-Linux组成的交换路由系统进行性能测试和分析，发现：在链路轻载或预留带宽的情况下，交换路由系统对数据流的服务质量优于传统路由系统；只有综合应用策略路由、数据报分类调度和标签交换才能实现Internet环境下对端到端服务质量的控制。     

Stateless overlay multicast with in-packet bloom filters

Due to the difficulty of deploying Internet protocol (IP) multicast on the Internet on a large scale, overlay multicast has been considered as a promising alternative to develop the multicast communication in recent years. However, the existing overlay multicast solutions suffer from high costs to maintain the state information of nodes in the multicast forwarding tree. A stateless overlay multicast scheme is proposed, in which the multicast routing information is encoded by a bloom filter (BF) and encapsulated into the packet header without any need for maintaining the multicast forwarding tree. Our scheme leverages the node heterogeneity and proximity information in the physical topology and hierarchically constructs the transit-stub overlay topology by assigning geometric coordinates to all overlay nodes. More importantly, the scheme uses BF technology to identify the nodes and links of the multicast forwarding tree, which improves the forwarding efficiency and decreases the false-positive forwarding loop. The analytical and simulation results show that the proposal can achieve high forwarding efficiency and good scalability.     

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     

水下传感网络中基于链路质量和位置的协作路由

水下传感网络是开发水域环境的有效技术手段。但在水下环境传输数据,信号衰减快,通信链路质量差,降低了数据包传递率。提出基于链路质量和位置的协作(LQLC)路由。LQLC路由引用协作路由思想,利用链路质量和节点能量信息,构建候选转发节点集;再从候选转发节点集中选择具有最优链路质量的节点作为转发节点;最后在候选转发节点集中选择离转发节点最近的节点作为协作节点。仿真结果表明,提出的LQLC路由提高了数据包传递率。     

MPLS security: an approach for unicast and multicast environments

Multi-Protocol Label Switching (MPLS) network architecture does not protect the confidentiality of data transmitted. This paper proposes a mechanism to enhance the security in MPLS networks by using multi-path routing combined with a modified (k, n) threshold secret sharing scheme. An Internet Protocol (IP) packet entering MPLS ingress router can be partitioned into n shadow (share) packets, which are then assigned to maximally node disjoint paths across the MPLS network. The egress router at the end will be able to reconstruct the original IP packet if it receives any k share packets. The attacker must therefore tap at least k paths to be able to reconstruct the original IP packet that is being transmitted, while receiving k???1 or less of share packets makes it hard or even impossible to reconstruct the original IP packet. In this paper, we consider the multicast case in addition to the unicast. To our best knowledge, no work has been published for MPLS multicast security. We have implemented our model and measured its time complexity on variable packets size.     

WSNs中基于转发区域调整的能效地理路由

针对无线传感网络(WSNs)的数据传输问题,提出基于转发区域调整的能效地理位置路由(FAEG)。FAEG限定了数据包的转发区域,构建候选转发节点集,并从节点集中选择权重大的节点传递数据包;通过节点剩余能量和离目的节点距离信息计算节点权重,使剩余能量大和离目的节点近的节点具有优先传递数据包的资格,提高了路由稳定性。节点遭遇路由空洞时,则调整转发区域,在更广范围内选择传输数据包的节点。仿真结果表明,提出的FAEG降低了能耗,并提高了数据包传递率。     

An implementation framework for trajectory-based routing in ad hoc networks

Routing in ad hoc networks is a complicated task because of many reasons. The nodes are low-memory, low-powered, and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad hoc networks. Also, for traffic engineering, multi-path capabilities are important. So, it is desirable to define routes at the source like in source based routing (SBR) while performing greedy forwarding at intermediate nodes.We investigate trajectory-based routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible.In this paper, we address various issues regarding implementation of TBR. We also provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms     

MPLS and the evolving Internet architecture

The Internet architecture has evolved over time, adapting to the needs of its users and incorporating new technology as it has been developed. The introduction of multiprotocol label switching (MPLS) as a part of the Internet forwarding architecture has immediate applications in traffic engineering and virtual private networks. In the longer term, MPLS may affect how traffic transits the Internet and the services that the Internet delivers     

Active routing

Active routing permits individual customers, network managers, or network owners to control the paths that their data takes through the network. The objective is to allow routing mechanisms that provide quality of service (QoS), mobility, etc., to be quickly deployed, without waiting for standards, and to allow different routing mechanisms, that provide similar services, to compete. The current work on label switching (MPLS) can also be used to give high level customers, such as virtual private networks (VPNs), more control over their paths. We show how active routing can extend the capabilities of MPLS. We address several implementation issues, including pricing and distributed sandboxes. Pricing or policing must be used to limit the resources that customers acquire, in order to encourage them to use network resources economically. Sandboxes must be used to limit the resources that the participants acquire, in order to limit the harm that they can inflict on other participants. Active routing creates a free market system where network providers compete to sell their resources and implementers compete to sell their active routing programs. We establish a framework to quantitatively compare networks and service providers. As an example, we route Internet protocol (IP) telephony over combinations of circuit and packet networks     

A Class of Shaped Deficit Round-Robin (SDRR) Schedulers

In the egress linecards of very high-speed Internet routers, packet schedulers must possess extremely low computation complexity and be able to handle flows of variable-length packets. Existing examples of such schedulers include deficit round-robin (DRR). In addition, it may be desirable to limit the variation about the peak-rate of certain egress flows (e.g., those under expedited forwarding (EF) service) so that their packets are not deemed out-of-profile downstream or possibly dropped as a result. Based on Shaped Weighted Round-Robin (SWRR), we propose a scheduler called Shaped Deficit Round-Robin (SDRR) and prove that it strictly limits the variation about the allocated peak-rate of every output flow. As such, our proposed SDRR is suitable for the modern Internet routers of a differentiated-service/MPLS.     

下一代网络路由交换关键技术研究

下一代网络是近来业界积极讨论的一项崭新网络技术,简要分析了下一代网络的特征,进而说明了下一代网络对路由交换技术的基本需求。着重针对几项路由交换关键技术进行了分析、论证和阐述,包括技术体制、宽带路由交换平台、大容量交换,高速数据转发、路由协议、MPLS协议以及业务服务质量保证等,并且概要设计了下一代宽带路由交换平台的整体框架,提出了一种高速数据转发技术的基本流程。     

High-speed IP routing with binary decision diagrams based hardware address lookup engine

With a rapid increase in the data transmission link rates and an immense continuous growth in the Internet traffic, the demand for routers that perform Internet protocol packet forwarding at high speed and throughput is ever increasing. The key issue in the router performance is the IP address lookup mechanism based on the longest prefix matching scheme. Earlier work on fast Internet protocol version 4 (IPv4) routing table lookup includes, software mechanisms based on tree traversal or binary search methods, and hardware schemes based on content addressable memory (CAM), memory lookups and the CPU caching. These schemes depend on the memory access technology which limits their performance. The paper presents a binary decision diagrams (BDDs) based optimized combinational logic for an efficient implementation of a fast address lookup scheme in reconfigurable hardware. The results show that the BDD hardware engine gives a throughput of up to 175.7 million lookups per second (Ml/s) for a large AADS routing table with 33 796 prefixes, a throughput of up to 168.6 Ml/s for an MAE-West routing table with 29 487 prefixes, and a throughput of up to 229.3 Ml/s for the Pacbell routing table with 6822 prefixes. Besides the performance of the scheme, routing table update and the scalability to Internet protocol version 6 (IPv6) issues are discussed.