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.     

Paris: An approach to integrated high-speed private networks

This paper describes a design of a high-speed packet switching system for integrated voice, video and data communications. The system makes use of a simplified network architecture in order to achieve the low packet delay and high nodal throughput necessary for the transport of voice and video. A prototype of this system has been implemented and is now being tested under a variety of packet traffic loads. We have demonstrated that this system provides a cost-effective solution for private integrated networks.     

三层以太网交换机CPU收发包相关问题分析

三层以太网交换机发展迅速,一方面网络设备的带宽及交换容量大幅提升,另一方面设备所支持的协议种类也随着用户的需求不断增加。如何在大业务量的网络环境下确保各设备之间协议包的正常交互,是以太网交换机设计面临的重要问题。文章以基于ASIC的三层以太网交换机为例,从CPU负载、软硬件队列配置、CPU和交换芯片的通信机制等方面入手,讨论并分析在多进程环境中与CPU收发包功能相关的一些典型问题,得到解决办法。解决方法对于网络处理器(NP)同样适用。     

Ethernet-over-SONET(EoS) over WDM in Optical Wide-Area Networks (WANs): Benefits and Challenges

Ethernet has been playing an increasingly important role in wide area networks (WANs), from both a service perspective and a transport-technology perspective. Unlike its dominant presence in local area networks (LANs), Ethernet in WANs has been increasing its popularity in three different directions, i.e., Ethernet-based layer-2 virtual private network (L2VPN) over layer-3 network, Ethernet over SONET (EoS), and Ethernet directly over WDM channels or optical fibers. In this paper, we investigate the benefits and challenges of using next-generation SONET/SDH techniques—namely SONET/SDH virtual concatenation (VCAT) and link-capacity adjustment scheme (LCAS)—to support Ethernet-based data services in intelligent optical WDM wide area networks. In particular, we evaluate the network performance improvement after employing VCAT. In order to fully utilize VCATs inverse-multiplexing capability, several simple and effective heuristic algorithms are proposed and evaluated.*Part of the work was accomplished while Keyao Zhu was a Ph.D. student in the Networks Research Lab. at University of California, Davis, under the supervision of Professor Biswanath Mukherjee. Summarized versions of this paper were presented at the IEEE/OSA Optical Fiber Communication Conferences OFC03 and OFC04 in Atlanta, GA, in March 2003 and in Los Angeles, CA, in March 2004, respectively.Corresponding author     

多业务宽带交换

网络交换经历着一系列发展演变;从电路交换到分组交换;从软件交换到硬件交换;从单一网络业务交换到多种业务交换。多业务宽带交换需要协议机制的支持,如业务类型划分,网络资源预约和用户业务最监控等。目前主要的宽带交换网技术有千兆比以太网,千兆比路由器网和ＡＴＭ网三种。文章最后论述了多业务宽带分组交换网的原理和结构。     

Experience with PACS in an ATM/Ethernet switched networkenvironment

Legacy local area network (LAN) technologies based on shared media concepts are not adequate for the growth of a large-scale picture archiving and communication system (PACS) in a client-server architecture. First, an asymmetric network load, due to the requests of a large number of PACS clients for only a few main servers, should be compensated by communication links to the servers with a higher bandwidth compared to the clients. Secondly, as the number of PACS nodes increases, the network throughput should not measurably cut production. These requirements can easily be fulfilled using switching technologies. Here asynchronous transfer mode (ATM) is clearly one of the hottest topics in networking because the ATM architecture provides integrated support for a variety of communication services, and it supports virtual networking. On the other hand, most of the imaging modalities are not yet ready for integration into a native ATM network. For a lot of nodes already joining an Ethernet, a cost-effective and pragmatic way to benefit from the switching concept would be a combined ATM/Ethernet switching environment. This incorporates an incremental migration strategy with the immediate benefits of high-speed, high-capacity ATM (for servers and high-sophisticated display workstations), while preserving elements of the existing network technologies. In addition, Ethernet switching instead of shared media Ethernet improves the performance considerably. The LAN emulation (LANE) specification by the ATM forum defines mechanisms that allow ATM networks to coexist with legacy systems using any data networking protocol. This paper points out the suitability of this network architecture in accordance with an appropriate system design     

Architecture design for ATM statistical multiplexers

Both high-speed packet switches and statistical multiplexers are critical elements in the ATM (asynchronous transfer mode) network. Many switch architectures have been proposed and some of them have been built, but relatively fewer statistical multiplexer architectures have been investigated to date. It has been considered that multiplexers are a special kind of switches which can be implemented with similar approaches. The main function of a statistical multiplexer, however, is to concentrate traffic from a number of input ports to a comparatively smaller number of output ports; ‘switching’ in the sense that a cell must be delivered to a specific output port is often not required. This implies that the channel grouping design principle, in which more than one path is available for each virtual circuit connection, can be applied in the multiplexer. We show that this technique reduces the required buffer memory and increases the system performance significantly. The performances of three general approaches for implementing an ATM statistical multiplexer are studied through simulations with various bursty traffic assumptions. Based on the best performing approach (sharing output channels and buffers), we propose two architecture designs to implement a scalable statistical multiplexer that is modularly decomposed into many smaller multiplexers by using a novel grouping network.     

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     

一种IPv6下直接基于IP封装的简单VPN模型

针对IPv6环境下IPSec实现VPN的复杂性,提出一种IPv6下直接基于Linux的IP封装来实现VPN的新体系框架,描述了扩展的IPIP报文结构和系统处理流程,并对直接基于IP封装的VPN和StrongSWAN实现之问进行了比较,得出新的系统在实现的结构上和性能上都具有较强的优势.     

智能虚交换技术研究和性能测试

本文首先针对以太网固有问题,提出了IVS(智能虚交换)技术体系,然后阐述了ⅣS核心运行机制,并对IVS系统进行性能测试,最后指出IVS是一种可用于城域范围的新型传送技术.     

AFDX-based flight test computer concept

With the introduction of the Airbus A380, the commercial aircraft industry was in the process of defining new standards that incorporate the latest digital information techniques, such as the avionics full-duplex switched Ethernet (AFDX) on-board, real-time network. The AFDX standard, a major innovation in aircraft technology first deployed on the Airbus A380, introduces telecom Ethernet-based technology as well as a switch connection topology, rather than part-to-part links or buses. This article describes the different modular elements of the ground and flight test computers, as well as the hardware and software tuning and performance analysis tools that have been developed around these computers. All of these elements are now in operation and have demonstrated the utility of the AFDX tools as real concepts that can be reused for other programs.     

Multiservice Ethernet access

Ethernet is evolving from its origins in the local area network into a cost-effective and reliable wide area network technology. Market research shows that business customers are moving away from traditional leased lines and selecting Ethernet as the access network technology of choice due to its low cost, simplicity and flexibility. Developments in Ethernet technology are now offering service providers the opportunity to deliver cost-effective carrier class Ethernet services. In particular, a new generation of Ethernet network termination equipment (NTE) is emerging which provides remote management, flexible bandwidth and fault diagnosis while supporting access to multiple services delivered over a single physical connection. This paper describes the advantages and potential cost savings of using Ethernet in the access network. A case study for a city demonstrates significant capital expenditure cost savings and highlights the advantages of using new Ethernet NTEs, which can be up to ten times cheaper than SDH technology, delivering equivalent bandwidth. Remote management and fault diagnosis features can also reduce operational expenditure by avoiding unnecessary site visits. A network architecture is presented which supports delivery of Ethernet services over a combination of circuit-switched and packet-switched domains. New standards which are maturing in the IETF, IEEE and ITU to support Ethernet delivery of interoperable services with carrier class reliability are also discussed.     

云数据中心的安全虚拟网络

虚拟网络安全是云计算安全的重要组成。为了保障虚拟网络流量的可控性和安全性,文中提出了一种基于Ethsec加密压缩技术的安全虚拟网络解决方案。该方案设计了虚拟化安全层、虚拟化安全交换机、安全虚拟网络管理平台和安全虚拟网络密钥分发系统等组件,通过文中提出的Ethsec技术,采用国产商用密码算法SM2和SM4算法,对虚拟机的以太网MAC帧进行压缩和解密,实现虚拟化安全交换机对所有虚拟网络流量的监控和分析。     

The knockout switch under nonuniform traffic

The knockout switch is a nonblocking, high-performance switch suitable for broadband packet switching. It allows packet losses, but the probability of a packet loss can be kept extremely small in a cost-effective way. The performance of the knockout switch was analyzed under uniform traffic. In this paper, we present a new, more general analytic model of the knockout switch, which enables us to evaluate the knockout switch under nonuniform traffic. The new model also incorporates the effects of a concentrator and a shared buffer on the packet loss probability. Numerical results for nonuniform traffic patterns of interest are presented     

Architecture, performance, and implementation of the tandem banyanfast packet switch

The authors propose a new space-division fast packet switch architecture based on banyan interconnection networks, called the tandem banyan switching fabric (TBSF). It consists of placing banyan networks in tandem, offering multiple paths from each input to each output, thus overcoming in a very simple way the effect of conflicts among packets (to which banyan networks are prone) and achieving output buffering. From a hardware implementation perspective, this architecture is simple in that it consists of several instances of only two VLSI chips, one implementing the banyan network and the other implementing the output buffer function. The basic structure and operation of the tandem banyan switching fabric are described, and its performance is discussed. The authors propose a modification to the basic structure which decreases the hardware complexity of the switch while maintaining its performance. An implementation of the banyan network using a high-performance BiCMOS sea-of-gates on 0.8-μm technology is reported     

The building blocks of a data-aware transport network: deploying viable Ethernet and virtual wire services via multiservice ADMs

SONET/SDH technologies constitute the core transport infrastructure of major telecom service providers worldwide. As the percentage of packet-oriented traffic in the overall traffic demand continues to rise, prompted by the widespread adoption of the Internet protocol suite, and recently by the fast adoption of Ethernet services, there is increasing pressure to improve the service provider's transport infrastructure in ways that make it data-aware and cost-effective for packet-oriented applications. Steps in this direction include the adoption of native physical interfaces, for Ethernet and storage area networks as service interfaces, or full integration of packet switching capabilities from Ethernet, resilient packet ring, and MPLS technologies. This article discusses the emerging building blocks for next-generation data-aware transport networks and next-generation transport network elements.     

20.8 Gb/s GaAs LSI self-routing switch for ATM switching systems

An 8×8 self-routing hardware switch providing 20.8 Gb/s throughput has been developed for asynchronous transfer mode (ATM) switching systems. The basic architecture of this switch is a Batcher-Banyan network. A new mechanism for data processing and distributing high-speed signals is proposed. This switching system consists of three LSIs using a 0.5-μm gate GaAs MESFET technology. These LSIs are a switching network LSI for exchanging packet cells with eight cell channels, a negotiation network for screening of cells destined for the same output port, and a demultiplexer LSI for converting the cell streams from the switching network LSI to the eight streams per channel. These LSIs are mounted in a 520-pin multichip module package. The total number of logic gates is 13.3 k, and the power dissipation is 24 W. The switching system fully operates at a data rate of 2.6 Gb/s, and its throughput is 20.8 Gb/s     

High-Performance Hybrid-Switching Optical Router for IP over WDM Integration

Because pure electrical routers with their bandwidth limitations can hardly keep up with the tremendous traffic growth in the Internet, optical routers based on various optical switching techniques including optical wavelength switching (OWS), optical burst switching (OBS), and optical packet switching (OPS) have been suggested to cope with this problem. However, because OBS and OPS are both in their early experimental phase and OWS only provides coarse granularity switching, a hybrid-switching optical router with combined OWS and electrical packet switching is a necessity in order to accommodate the entire multi-granularity traffic with multi-service requirements in a cost-effective manner. Its coordination capability of optical circuit switching and electrical packet switching enables efficient/intelligent usage of network resources. In this paper, we first review research and developments of such IP routers employing optical switching/interconnection techniques and examine how these techniques can be used inside routers to scale node capacity and to improve optical Internet performance. We also present and study the performance of a terabit optical router with an optical-electrical hybrid-switching fabric. The node architecture is based on the idea of IP over WDM integration with Generalized Multi-Protocol Label Switching (GMPLS). The network-level performance evaluations show that the proposed hybrid-switching optical router is a cost-effective solution for building the next generation GMPLS-based multi-granularity optical Internet.     

网络存储的发展历程及新兴的iSCSI

目前SAN和NAS存储正在迅速发展，DAS的生存空间越来越小。今天超过1／3的存储是网络化的，如果不是因为FC的高成本和复杂性．这个数字还会更大。iSCSI是IETF一种新的标准协议．它将SCSI命令压缩到TCP／IP包．使数据块在IP网络上传播。和FC-SAN相比．高速千兆iSCSI耙SCSI、以太网和TCP／IP结合起来，具有许多优势．如建立在稳定和熟悉的标准上；较低的总拥有成本，安装和维修费用很低；较高程度的可操作性，减少了异构网络和电缆．使用一般的以太网交换机而不是特殊的FC交换机；等等。     

基于以太网传输的E1到IP适配设计

利用包网络传输成本的优势,在现有的以太网 /IP网络上仿真电路业务,可以实现传统时分复用(TDM)设备间的无缝连接,从而保护投资。本文提出了在基于以太网的IP网络上传输E1业务的一种整体解决方案,介绍了适配电路的设计和实现。