基于LACP多激活检测方法和处理机制的研究

虚拟交换机技术可将汇聚层的两台物理设备虚拟为一台虚拟设备,该虚拟设备通过跨设备链路聚合与接入层设备相连.这种简化后的组网因无需配置MSTP、VRRP而简化了网络配置.当成员设备出现故障时,接入层设备依靠跨设备链路聚合,提高了网络连接可靠性.但虚拟设备内,成员设备间链路出现故障时,虚拟设备发生分裂,形成两个虚拟设备,出现多激活,导致网络瘫痪.因此如何快速检测到多激活及检测后的处理,对虚拟交换技术的发展是极其重要的,介绍了一种多激活检测方法,可较快速地检测到多激活,是一种高效的多激活处理方法;还提出了一种多激活处理方法,可有效保证网络业务正常运行.     

VRRP应用研究

VRRP(Virtual Router Redundancy Protocol)虚拟路由冗余协议,能解决局域网主机访问外部网络的可靠性问题。通过以华为S9300系列交换机为载体,给出了如果配置VRRP来实现提高局域网访问外部网络的可靠性。     

IP城域网引入虚拟交换机技术的研究

首先重点介绍虚拟交换机及部署方式,多虚一技术和一虚多技术两种虚拟技术在网络中的应用,然后论述虚拟交换机在现网中的实验和数据统计分析,最后给出虚拟交换机在城域网中的部署方案建议,虚拟交换技术的引入不仅能够大幅降低故障率,减轻运维压力,提高链路和端口的利用率,降低总体投资成本,而且还能够为后期城域网的大规模提速打下坚实的网络基础。     

利用IP宽带网开展虚拟局域网业务的安全措施

1　物理链路的安全性问题为了防止交通肇事、偷盗、线路改道、自然灾害等造成通信链路中断 ,影响数据传输 ,在网络结构上 ,将核心交换机和 6个骨干交换节点建成光纤环网 ,保证链路上有冗余光纤和冗余的路由备份。在主干环上 ,对层二的ＶＬＡＮ采用快速Ｓｐａｎｎｉｎｇ -ｔｒｅｅ技术 ,保证链路快速自愈。另外 ,随着业务的发展 ,逐步将所有的边缘交换节点连成环网 ,确保网络安全运营。2　设备的安全性问题设备的安全性主要表现为设备的稳定运行和配置的安全性。美国Ｅｘｔｒｅｍｅ网络设备是电信级运营产品 ,设备安全运营无故障率达 99.999%…     

基于MPLS第二层VPN

虚拟专用网络（VPN）是目前构建类似企业网等专用网络的主要方法，而多协议标签交换（MPLS）技术又是目前唯一标准化的IP交换技术，随着IP网络主干链路宽带的不断提高，IP网络的骨干路由器也随之成为标签交换路由器（LSR），用标签交换路径（LSP）作为互连专用网络各个本地LAN的点对点虚拟专用链路也日益成为用户和ISP的选择。本结合一个实例详细介绍了基于MPLS第二层VPN的工作机制。     

校园网中的三层交换和虚拟局域网技术

讨论了局域网技术的发展，校园网采用虚拟局域网技术的原因和必要性，虚拟局域网的概念、分类和特点以及三层交换和路由的区别。并用一些例子介绍了在校园网中利用三层交换和基于端口的虚拟局域网技术的网络配置方法。     

基于三层交换的VLAN设置技术研究

基于三层交换与路由技术的交换机的应用,已从最初网络骨干层、汇聚层渗透到接入层。论文对三层交换和路由技术、Trunk和VTP技术、VLAN技术的应用进行了全面详尽的描述,并介绍了思科交换机的VLAN配置方法。     

基于三层交换的虚拟局域网技术在校园网中的应用

在校园网的建设中,应用三交换技术作为局域网搭建方式已经成为了一种普遍流行的方式。基于三层交换的虚拟局域网技术主要采用VLAN技术对网段进行划分,可以满足校园网络应用中不同方式的网络访问与应用。其对复杂的数据和不同类型的数据都具有良好的网络传输效能。文章首先对三层交换技术进行介绍,主要介绍涉及到的VLAN技术和三层交换技术原理。其次根据学校局域网应用特点设计基于三层交换技术的校园虚拟局域网,对网络结构设计和VLAN规划设计进行介绍。最后,针对基于三层交换的虚拟局域网技术在校园网中的应用实现介绍虚拟服务器的安装与配置和系统的调试。     

OBS网络中的虚拟突发交换技术

针对由于网络复杂度提高,突发数据在预留时冲突可能性增大,导致OBS网络性能下降的情况,提出OBS网络中的虚拟突发交换技术和相应的实现技术。其汇聚机制是基于服务类别的虚拟汇聚,调度策略对应有两种：非抢占调度策略和抢占调度策略。利用虚拟突发交换技术有利于减少信道碎片,提高链路利用率,提供可靠的QOS保证。用OPNET系统仿真工具进行验证,结果表明：虚拟突发交换与OBS传统交换方式相比有较高网络链路的利用率,较少的控制分组和数据突发的丢包率,增加了整个网络的吞吐量。     

一种云计算虚拟化平台网络安全模式的研究

针对目前WMware虚拟化平台的网络特点及网络要求,从网络安全与网络性能两个方面,对WMware虚拟化平台的虚拟交换机网络进行分析,从虚拟主机功能分类、网络安全、网络规划、网络性能负载均衡等几个方面进行探讨。结合目前市面上常见的不同网口数的物理服务器的情况,通过3种类型的虚拟化负载均衡技术,在保障安全的基础上,同时优化网络的性能,针对目前虚拟化技术的网络安全性能方面给出一种网络安全解决方案和网络链路聚合方案。     

VRRP及其在专网中的应用

随着网络应用的不断普及,用户对网络的可靠性提出越来越高的要求。采用虚拟路由器冗余协议(VRRP)的优势在于不需要在终端进行动态路由和路由发现协议的配置,即可以获得一个高可靠性的缺省路由通道。介绍了VRRP的基本原理,结合在专网上进行的验证性试验,提出在该专网上应用VRRP进行IP业务可靠传输的方案。该方案提高了网络的稳定性和可靠性,节省了用户投资。     

Designing a practical ATM LAN

The adaptor cards and driver software for workstations and local asynchronous transfer mode (ATM) switches and switch control software used in an ATM local area network (LAN) system are discussed. It is shown that the ATM hardware and software components together provide services that are essential for ATM to be considered a realistic alternative to current shared-media LANs. These services include: completely transparent support for the TCP/IP protocol suite, an application programming interface for full access to the underlying ATM capabilities, support for AAL5, AAL3/4, and the null AAL, both connection-oriented and connectionless service, dynamic connection establishment or switched virtual circuits, resource reservation of guaranteed bandwidth and quality of service, full-bandwidth multicast and broadcast, virtual path and channel routing among multiple switches, automatic configuration and failure recovery, dynamic address assignment and internetwork address resolution, and network management via the simple network management protocol (SNMP)     

A MEMS reconfigurable matching network for a class AB amplifier

This letter presents the design of a reconfigurable amplifier with an adaptive matching network implemented by shunt MEMS switches. In particular, the MEMS switches are used as capacitive stubs in double-stub matching circuit designs. The effective capacitance of the switches can be varied by switch activation which results in a change of the matching configuration. The RF response of the adaptive matching network is studied and the power performance of the amplifier is presented.     

一种虚拟路由冗余协议负载均衡技术实现机制

标准VRRP（虚拟路由器冗余协议）解决在配置默认网关环境下消除网络单点故障问题,其协议自身不够灵活,即虚拟路由器中只有主设备进行流量转发,其他备用设备均作为备份不进行流量转发,无法负载分担,不能最大程度提高带宽和设备利用率。针对该局限,在此基于与某公司的合作项目,论述了一种虚拟路由冗余协议负载均衡实现机制,在标准VRRP协议分析研究基础上引入虚拟转发器和转发状态机,实现一个虚拟IP对应多个虚拟MAC的机制,无需配置多个备份组就能同时实现路由冗余备份和流量负载均衡,使局域网内用户能够通过每台虚拟转发器与外界通信,极大地提高资源利用率,最后以实验验证了设计可行性。     

Autonet: a high-speed, self-configuring local area network usingpoint-to-point links

Autonet is a self-configuring local area network composed of switches interconnected by 100 Mb/s, full-duplex, point-to-point links. The switches contain 12 ports that are internally connected by a full crossbar. Switches use cut-through to achieve a packet forwarding latency as low as 2 ms/switch. Any switch port can be cabled to any other switch port or to a host network controller. A processor in each switch monitors the network's physical configuration. A distributed algorithm running on the switch processor computes the routes packets are to follow and fills in the packet forwarding table in each switch. With Autonet, distinct paths through the set of network links can carry packets in parallel, allowing many pairs of hosts to communicate simultaneously at full link bandwidth. A 30-switch network with more than 100 hosts has been the service network for Digital's Systems Research Center since February 1990     

Crosstalk-free conjugate networks for optical multicast switching

High-speed photonic switching networks can switch optical signals at the rate of several terabits per second. However, they suffer from an intrinsic crosstalk problem when two optical signals cross at the same switch element. To avoid crosstalk, active connections must be node disjoint in the switching network. In this paper, a sequence of decomposition and merge operations, called conjugate transformation, performed on each switch element to tackle this problem, is proposed. The network resulting from this transformation is called the conjugate network. By using the numbering schemes of networks, the authors prove that if the route assignments in the original network are link disjoint, their corresponding ones in the conjugate network would be node disjoint. Thus, traditional nonblocking switching networks can be transformed into crosstalk-free optical switches in a routine manner. Furthermore, it has been shown that crosstalk-free multicast switches can also be obtained from existing nonblocking multicast switches via the same conjugate transformation.     

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.     

Performance comparison of switch architectures with shareable parallel memory modules

The class of switches with shareable parallel memory modules include those switches that use parallel memory modules which are physically separate but logically shared. The two main classes of such architectures namely the Shared Multibuffer (SMB) based switch and the Sliding-Window (SW) based packet switch both deploy shareable parallel memory modules, however they differ in the switching scheme used by them to store incoming packets and transfer packets among different switch ports. In this letter, we investigate and compare the performance of switching schemes deployed by these two classes of switching architectures. We compare throughput and packet loss performance of these two switches under conditions of identical traffic type, switch configuration and memory resource deployed.     

MPCP based active optical access network with PLZT high-speed optical switch

An active optical access network architecture with our newly developed PLZT ((Pb,La)(Zr,Ti)O₃) high-speed optical switch is introduced, with a view to realizing the next-generation high capacity scalable access network. This system is developed based on the latest IEEE standard of PON (10G-EPON; IEEE802.3av) in consideration of the coordination with future high capacity PON. PLZT high-speed optical switches are able to switch an optical signal at nano-second speed (<5-10 ns). Generally, the merits of using optical switches are increasing the number of subscribers and transmission distance easily, preventing malicious ONUs from interfacing with the communication between OLT and the other ONUs, realizing fast fiber and OLT protection/restoration and providing various services by controlling optical switches dynamically. This paper focuses on two key technologies; a PLZT optical switch and a new discovery process for active optical access network based on MPCP defined at IEEE802.3. A major challenge in designing active optical access network is supporting the discovery process of MPCP because it does not offer broadcast transmission unlike the regular PON. We propose here a new discovery process; it has been tested successfully in an implementation of our proposed system.