Tree-Based Proactive Routing Protocol for Wireless Mesh Network
Routing Protocol
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7.2 路由协议路由协议是路由器软件中的重要组成部分。
路由器为互联的网络之间选择最佳的通信路都是通过这些路由协议来完成的。
路由协议的作用还在于建立以及维护路由表。
路由表用于为每个IP包选择输出端口或下一跳地址。
开放的路由协议主要包含RIP、OSPF、IS-IS以及Cisco公司私有的IGRP。
RIP是距离向量路由协议,一般用于企业内部小规模网络。
OSPF 和IS-IS协议的原理和实现都类似,是链路状态协议,一般用于大规模企业网或运营商网络。
7.2.1 静态路由与默认路由静态路由是在路由器中设置固定的路由表,即指定固定的传输路径,除非网络管理干预,否则将不会自动更改。
所以当网络的拓扑结构或链路的状态发生变化时,需要手动去修改路由表中相关的静态路由信息。
静态路由信息在默认情况下是私有的,不会传递给其他的路由器。
当然,网管员也可以通过对路由器进行设置使之成为共享的。
1.静态路由静态路由是一种特殊的路由,它由管理员手工配置而成。
通过静态路由的配置可建立一个互通的网络,但这种配置问题在于:当一个网络故障发生后,静态路由不会自动发生改变,必须有管理员的介入。
在组网结构比较简单的网络中,只需配置静态路由就可以使路由器正常工作,仔细设置和使用静态路由可以改进网络的性能,并可为重要的应用保证带宽。
静态路由还有如下的属性:可达路由。
正常的路由都属于这种情况,即IP 报文按照目的地标示的路由被送往下一跳,这是静态路由的一般用法。
目的地不可达的路由。
当到某一目的地的静态路由具有“丢弃”属性时,任何去往该目的地的IP报文都将被丢弃,并且通知源主机目的地不可达。
目的地为黑洞的路由。
当到某一目的地的静态路由具有“黑洞”属性时,任何去往该目的地的IP报文都将被丢弃,并且不通知源主机。
其中“丢弃”和“黑洞”属性一般用来控制本路由器可达目的地的范围,辅助网络故障的诊断。
通过配置静态路由,可以人为地指定对某一网络访问时所要经过的路径。
水声通信组网技术第五讲水声网络路由
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2020/4/12
第六讲 水下通信网络的路由机制
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1.水声网络路由概述 ——Ad Hoc网络路由
网络拓扑动态变化的特性使得传统的有线网路由 协议产生大量的控制信息。不仅会消耗掉原本非 常有限的带宽资源,而且还会增加信道竞争,大 量消耗便携终端的能量。
可以通过无线声链路构成任意拓扑 这种网络建立快捷、灵活 可广泛应用于水下军事防御、海洋环境监测和保护、
海洋地质灾害预报、矿产资源勘探等场合
2020/4/12
第六讲 水下通信网络的路由机制
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Seaweb 2005 UUV Experiments Monterey Bay, May 9-11, July 20-22
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1.水声网络路由概述
路由问题 • 解决网络中结点如何将分组从源结点正确的发送
到目的结点的问题 • 即结点如何对分组进行转发的问题 路由协议 • 路由算法:在获知网络拓扑和链路状态的条件下,
选择源结点到达目的结点的路径的法则。如最小 代价路由选择算法(代价可以为时延、距离、能 耗等) • 路由策略:解决路由的选择如何适应网络拓扑和 状态变化的问题
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第五讲 水声网络路由
3. 三种典型的路由协议
DSR (Dynamic Source Routing) AODV (Ad Hoc On-demand Distance Vector Routing) OLSR (Optimized Link State Routing)
2020/4/12
第六讲 水下通信网络的路由机制
• 优点:不存在特殊结点,路由协议的鲁棒性较好, 通信流量平均的分散在网络中,不需要结点移动 性管理
【2015-12】水下传感器网络综述
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1水声通信由于声音(Acoustic)在水中的衰减低,声波通信成为在水下环境中最通用和应用最广泛的技术,尤其是在热稳定的深水区域。
声波通信的主要限制因素是浅水区域中的温度梯度差异、海面噪声和反射折射引起的多径传播;次要的限制因素是水中声速(约为1500米/秒)慢,也限制了其通信效率。
所以,水声通信受到严重的带宽限制和干扰限制,难以实现短距离、高带宽通信。
综观整个水声通信的发展历程,就是不断地与这些干扰相抗争的过程。
例如:根据不同的干扰特点,选择抗干扰能力强的编(解)码方法和调制方式;采用各种抑制干扰的技术;采用分集的办法来抵抗衰落;采用均衡技术抵消信道缺陷引起的畸变;采用自适应技术来适应信道特性的变化以及增加功率等。
水声通信在几KHz到几十KHz的带宽下,可以实现1-2000公里距离的通信,在小于1公里范围的短距离通信中,水声通信在几十KHz带宽下,数据传输速率可达100kbps,带宽效率可达几个bits/sec/Hz。
2水下无线通信网络安全关键技术研究研制低成本、高能效、高可靠性、高安全性的水下无线通信网络对于海洋环境监控、海洋资源开发等研究领域具有重要的理论意义和经济价值。
由于受自身特性限制和水声通信环境制约,水下无线通信网络面临各种威胁和攻击,然而现有的水下通信研究多以节省能耗、延长网络寿命为出发点,忽视了潜在的安全问题。
因此,研究现有水下无线通信技术存在的安全隐患,针对其面临的安全威胁和安全需求,设计适用于水下无线通信网络的安全技术和安全体系,具有重要的意义。
本文对水下无线通信网络的若干安全关键技术进行了研究,并提出了一种适用于水下无线通信网络的安全体系。
无线传感器网络(Wireless Sensor Networks, WSN)最早可以追溯到20 世纪末,它以其低成本、低能耗、自组织和分布式的特点为网络带来了一场信息感知的变革。
无线传感器网络在城市管理、环境监测、军事国防、生物医疗等领域都表现出了很好的应用前景。
Routing Protocol
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RIPRIP 路由协议是目前在使用的路由协议中最简单的一种,RIP是为TCP/IP环境中开发的第一个路由协议标准,距离矢量协议,使用UDP520端口来操作1. 它每30秒发送一次广播更新,正因为它是使用了广播进行发送的更新,所以在大型网络中,如果路由条目多,所有主机都会监听接受路由更新,因此这样的路由协议是非常消耗带宽的。
2. 不适用触发更新。
触发更新就是一旦拓扑有所变化触发就会发送更新包。
加上它是每30秒钟发送一次,所以它的拓扑收敛速度非常的慢,在当今现在目前使用的网络中是不能接受的。
3.有类路由,也就是它不能发送子网掩码,这种也是在大型网络所不能接受的。
也正因为它是有类路由,所以它广播的路由可以没有掩码,这也就意味着能够在整个网络中进行发送。
默认为ver1RIP v2普遍应用于无类域间路由CIDR和可变长子网掩码VLSM支持无类路由和通过网络中子网掩码的发送,支持触发更新RIPv2的更新包使用广播地址224.0.0.9进行广播能够配置邻居包,配置了邻居后,能够使用单播进行发送,这样就减少了网络带宽流量支持在路由器之间支持Authentication无类路由协议在发送子网的时候会自动汇总,也就是意味着我一段10.10.10.0/24的网络将会被他使用10.0.0.0/8的这个大网络进行汇总过去。
一般在设备上默认都是汇总的。
所以我们在配置的路由协议的时候不要忘记配置no auto-summaryEIGRP它全称是增强型内部网关路由协议,属于无类路由协议它是一个非常流行的路由协议,(当然这是对cisco的设备来讲的。
别的设备不支持。
因为这是Cisco的私有路由协议)它是一个非常好的路由协议,当一个网络中规划好IP addr,它将会表现的更加出众特别是在大型网络中。
它是一种距离矢量协议,但它的特性看起来特别像是链路状态协议。
1.使用触发更新,只在拓扑有变更的时候才会有更新。
2.收敛速度非常快,特别是在大型网络中,一个网络中使用RIP 要数分钟的收敛,但通过EIGRP只需要几秒。
ip route学习
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路由协议(routing protocol):用于routers动态寻找网络最佳路径,保证所有routers拥有相同的路由表.一般,路由协议决定数据包在网络上的行走的路径.这类协议的例子有OSPF,RIP,IGRP,EIGRP等可路由协议(routed protocol):当所有的routers知道了整个网络的拓扑结构以后,可路由协议就可以用来发送数据.一般的,可路由协议分配给接口,用来决定数据包的投递方式.这类例子有IP和IPX 路由:把1个数据包从1个设备发送到不同网络里的另1个设备上去.这些工作依靠routers来完成.routers并不关心主机,它们只关心网络的状态和决定网络中的最佳路径router可以路由数据包,必须至少知道以下状况:1.目标地址(destination address)2.可以学习到远端网络状态的邻居router3.到达远端网络的所有路线4.到达远端网络的最佳路径5.如何保持和验证路由信息The IP Routing Process路由原理:当IP子网中的一台主机发送IP包给同一IP子网的另一台主机时,它将直接把IP包送到网络上,对方就能收到.而要送给不同IP于网上的主机时,它要选择一个能到达目的子网上的router,把IP包送给该router,由它负责把IP包送到目的地.如果没有找到这样的router,主机就把IP包送给一个称为缺省网关(default gateway)的router上.缺省网关是每台主机上的一个配置参数,它是接在同一个网络上的某个router接口的IP地址,router转发IP包时,只根据IP包目的IP地址的网络号部分,选择合适的接口,把IP包送出去.同主机一样,router也要判定接口所接的是否是目的子网,如果是,就直接把包通过接口送到网络上,否则,也要选择下一个router来传送包.router也有它的缺省网关,用来传送不知道往哪儿送的IP包.这样,通过router把知道如何传送的IP包正确转发出去,不知道的IP包送给缺省网关,这样一级级地传送,IP包最终将送到目的地,送不到目的地的IP包则被网络丢弃了当主机A发送个IP包到主机B,目标MAC地址使用的是默认网关的以太网接口地址.这是因为帧不能放置在远端网络.show ip route:查看路由表信息,比如:Router#sh ip route(略)Gateway of last resort is not setC 192.168.10.0/24 is directly connected, FastEthernet0/0C 192.168.20.0/24 is directly connected, Serial 0/0Router#C代表的是:直接相连Configuring IP Routing in Our Network当1个router收到1个目标网络号没有在路由表中列出的包的时候,它并不发送广播寻找目标网络,而是直接丢弃它几种不同类型的路由:1.静态路由(static routing)2.默认路由(default routing)3.动态路由(dynamic routing)Static Routing静态路由:手动填加路由线路到路由表中,优点是:1.没有额外的router的CPU负担2.节约带宽3.增加安全性缺点是:1.网络管理员必须了解网络的整个拓扑结构2.如果网络拓扑发生变化,管理员要在所有的routers上手动修改路由表3.不适合在大型网络中静态路由的配置命令:ip route [dest-network] [mask] [next-hop address或exit interface][administrative distance] [permanent]ip route:创建静态路由dest-network:决定放入路由表的路由表mask:掩码next-hop address:下1跳的router地址exit interface:如果你愿意的话可以拿这个来替换next-hop address,但是这个是用于点对点(poi nt-to-point)连接上,比如广域网(WAN)连接,这个命令不会工作在LAN上administrative distance:默认情况下,静态路由的管理距离是1,如果你用exit interface代替next -hop address,那么管理距离是0permanent:如果接口被shutdown了或者router不能和下1跳router通信,这条路由线路将自动从路由表中被删除.使用这个参数保证即使出现上述情况,这条路线仍然保持在路由表中静态路由的具体配置:Router Network Address Interface AddressRouterA 192.168.10.0 fa0/0 192.168.10.1192.168.20.0 s0/0 192.168.20.1RouterB 192.168.20.0 s0/0 192.168.20.2192.168.40.0 s0/1 192.168.40.1192.168.30.0 fa0/1 192.168.30.1RouterC 192.168.40.0 s0/0 192.168.40.2192.168.50.0 fa0/0 192.168.50.1准备工作:先配置RouterA,B和C的基本信息,注意RouterB作为DCE提供时钟频率:RouterA(config)#int fa0/0RouterA(config-if)#ip address 192.168.10.1 255.255.255.0RouterA(config-if)#no shutRouterA(config-if)#int s 0/0RouterA(config-if)#ip address 192.168.20.1 255.255.255.0RouterA(config-if)#no shutRouterA(config-if)#^ZRouterA#copy run startRouterB(config)#int fa0/0RouterB(config-if)#ip address 192.168.30.1 255.255.255.0RouterB(config-if)#no shutRouterB(config-if)#int s 0/0RouterB(config-if)#ip address 192.168.20.2 255.255.255.0RouterB(config-if)#clock rate 64000RouterB(config-if)#no shutRouterB(config-if)#ip address 192.168.40.1 255.255.255.0RouterB(config-if)#clock rate 64000RouterB(config-if)#no shutRouterB(config-if)#^ZRouterB#copy run startRouterC(config)#int fa0/0RouterC(config-if)#ip address 192.168.50.1 255.255.255.0RouterC(config-if)#no shutRouterC(config-if)#int s 0/0RouterC(config-if)#ip address 192.168.40.2 255.255.255.0RouterC(config-if)#no shutRouterC(config-if)#^ZRouterC#copy run start配置RouterA静态路由:RouterA了解自己的网络192.168.10.0和192.168.20.0(直接相连),所以RouterA的路由表必须加入192.168.30.0和192.168.40.0, 192.168.50.0的信息,注意下1跳接口,如下: RouterA(config)#ip route 192.168.30.0 255.255.255.0 192.168.20.2RouterA(config)#ip route 192.168.40.0 255.255.255.0 192.168.20.2RouterA(config)#ip route 192.168.50.0 255.255.255.0 192.168.20.2验证路由信息:RouterA#sh ip route(略)S 192.168.50.0 [1/0] via 192.168.20.2(略)S代表静态路由,[1/0]分别为管理距离和度配置RouterB静态路由:RouterB所必须学习到的网络应该是192.168.10.0和192.168.50.0,注意它们的下1跳接口地址,配置如下:RouterB(config)#ip route 192.168.10.0 255.255.255.0 192.168.20.1RouterB(config)#ip route 192.168.50.0 255.255.255.0 192.168.40.2配置RouterC静态路由:RouterC所必须学习到的网络应该是192.168.10.0,192.168.20.0和192.168.30.0,注意它们的下1跳接口地址,配置如下:RouterC(config)#ip route 192.168.10.0 255.255.255.0 192.168.40.1RouterC(config)#ip route 192.168.20.0 255.255.255.0 192.168.40.1RouterC(config)#ip route 192.168.30.0 255.255.255.0 192.168.40.1Verifying Your Configuration根据上面的拓扑结构,我们来验证下是否能够端到端的ping通:RouterC#ping 192.168.10.1(略)Sending 5, 100-byte ICMP Echos to 192.168.10.1, timeout is 2 seconds:!!!!!(略)RouterA#ping 192.168.50.1(略)Sending 5, 100-byte ICMP Echos to 192.168.50.1, timeout is 2 seconds:!!!!!(略)2端都能ping通,说明没问题Default Routing默认路由:一般使用在stub网络中,stub网络是只有1条出口路径的网络.使用默认路由来发送那些目标网络没有包含在路由表中的数据包.根据上面的拓扑图,你就不能把默认路由定义在RouterB上,因为RouterB拥有不止1个出口路径接口.其实你可以把默认路由理解成带通配符(wildcard)的静态路由配置默认路由:首先要去掉之前配置的静态路由RouterC(config)#no ip route 192.168.10.0 255.255.255.255 192.168.40.1RouterC(config)#no ip route 192.168.20.0 255.255.255.255 192.168.40.1RouterC(config)#no ip route 192.168.30.0 255.255.255.255 192.168.40.1接下来配置默认路由:RouterC(config)#ip route 0.0.0.0 0.0.0.0 192.168.40.1额外的命令,使各个接口打破分类IP规则,12.x的IOS默认包含这条命令,如下:RouterC(config)#ip classless再验证下:RouterC(config)#^ZRouterC#sh ip route(略)S* 0.0.0.0/0 [1/0] via 192.168.40.1S*代表默认路由Dynamic Routing动态路由协议,有很多优点,灵活等等,但是缺点也有,比如占用了额外的带宽,CPU负荷高组网利用到的2种路由协议:内部网关协议(Interior Gateway Protocols,IGPs)和外部网关协议(E xterior Gateway Protocols,EGPs)自治系统(Autonomous System,AS):同1个管理域的网络集合,意味着在这里面的所有routers共享相同的路由表信息IGPs:在相同的AS内交换路由信息EGPs:AS间的通信Routing Protocol BasicsAdministrative Distances管理距离(AD): 0到255之间的1个数,它表示一条路由选择信息源的可信性值.该值越小,可信性级别越高.0为最信任,255为最不信任即没有从这条线路将没有任何流量通过.假如1个router收到远端的2条路由更新,router将检查AD,AD值低的将被选为新路线存放于路由表中.假如它们拥有相同的AD,将比较它们的度(metric).度低的将作为新线路.假如它们的AD和度都一样,那么将在2条线路做均衡负载.一些常用路由协议默认的AD:1.直接相连:02.静态路由:13.EIGRP:904.IGRP:1005.OSPF:1106.RIP:120记住,如果你在条线路上配置了静态路由,又配置了RIP,默认情况下,router只会使用静态路由,因为它的AD为1小于RIP的ADRouting Protocols3种路由协议:1.距离向量(distance vector)2.链路状态(link state)3.混合型(hybrid)距离向量:用于根据距离(distance)来判断最佳路径,当1个数据包每经过1个router时,被称之为经过1跳.经过跳数最少的则作为最佳路径.这类协议的例子有RIP和IGRP,它们将整个路由表向与它们直接相连的相邻routers链路状态:也叫最短路径优先(shortest-path-first)协议.每个router创建3张单独的表,1张用来跟踪与它直接相连的相邻router;1张用来决定网络的整个拓扑结构;另外1张作为路由表.所以这种协议对网络的了解程度要比距离向量高.这类协议例子有OSPF混合型:综合了前2者的特征,这类协议的例子有EIGRPDistance-Vector Routing Protocols距离向量路由算法将完整的路由表传给相邻router,然后这个router再把收到的表的选项加上自己的表来完成整个路由表,这个叫做routing by rumor,因为这个router是从相邻router接受更新而非自己去发现网络的变化。
HP 6125G 1Gb 刀片交换机说明说明书
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HP 6125G Ethernet Blade Switch
DA - 14427 Worldwide — Version 4 — September 30, 2013
Page 2
QuickSpecs
Standard Features
HP 6125G Ethernet Blade Switch
Performance Management
1. Unit ID (UID) LED 2. Ejector lever 3. IRF/SFP port 4. SFP port 5. Release tab 6. 10/100/1000Base-T auto-sensing Ethernet port
HP 6125G Blade Switch 7. Reset button 8. 10/100/1000Base-T Ethernet port LED 9. Console port 10. SFP port LED 11. IRF/SFP port LED 12. Health LED
IEEE 802.1X user authentication MAC-based authentication with RADIUS server Access Control Lists (ACLs) Secure FTP STP Root Guard DHCP Protection from unauthorized DHCP servers IP Source Guard Dynamic ARP protection to prevent eavesdropping Guest VLAN Endpoint Admission Defense (EAD) RADIUS/TACACS+ Secure management via SSHv2 and SNMPv3 Unicast Reverse Path Forwarding (URPF)
思科华为生成树对接
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思科与华为生成树协议的对接Cisco交换机支持的生成树协议类型Cisco交换机所支持的生成树协议类型分别有:PVST(Per VLAN Spanning Tree)、PVST+(Per VLAN Spanning Tree Plus)、Rapid-PVST+(Rapid Per VLAN Spanning Tree Plus)、MISTP(Multi Instance Spanning Tree Protocol)和MST(Multiple Spanning Tree)。
在使用IOS 12.2及之后版本的catalyst系列交换机中,支持PVST+、Rapid-PVST和MST三种类型STP协议。
同时,Cisco所采用的STP协议的BPDU报文格式和标准STP协议的BPDU报文格式不一样,而且发送的目的地址也改成了C友商自己的保留地址01-00-0C-CC-CC-CD。
H3C交换机支持的生成树协议类型H3C交换机支持的生成树协议有三种类型,分别是STP(IEEE 802.1D)、RSTP(IEEE 802.1W)和MSTP(IEEE 802.1S),这三种类型的生成树协议均按照标准协议的规定实现,采用标准的生成树协议报文格式,大多数交换机采用固定的MAC地址00-E0-FC-09-BC-F9作为生成树协议报文的源MAC地址,目的MAC地址为01-80-C2-00-00-00。
当Cisco设备使用Trunk端口与其他厂商设备的Trunk端口互联时,虽然可以做到STP的互通,以及消除环路,但是无法做到PVST协议自身的负载,原因是在其他VLAN中H3C 的设备会把Cisco的BPDU报文当作普通的多播报文进行转发,而不会处理这些报文。
Cisco设备在非VLAN1中的BPDU报文不是标准的STP协议BPDU报文,而是其私有的PVST协议报文。
当H3C交换机与Cisco交换机使用MSTP协议互通时,必须要在全局配置stpconfig-digest-snooping命令,同时在与Cisco设备互联的端口上也要配置该命令,才能完成与Cisco的域内MSTP协议互通。
移动Adhoc网络的特点及应用
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移动Adhoc⽹络的特点及应⽤移动Ad hoc⽹络的特点及应⽤1 Ad hoc⽹络的定义Ad hoc⽹是⼀种多跳的、⽆中⼼的、⾃组织⽆线⽹络,⼜称为多跳⽹(Multi-hop Network)、⽆基础设施⽹(Infrastructure less Network)或⾃组织⽹(Self-organizing Network)。
整个⽹络没有固定的基础设施,每个节点都是移动的,并且都能以任意⽅式动态地保持与其它节点的联系。
在这种⽹络中,由于终端⽆线覆盖取值范围的有限性,两个⽆法直接进⾏通信的⽤户终端可以借助其它节点进⾏分组转发。
每⼀个节点同时是⼀个路由器,它们能完成发现以及维持到其它节点路由的功能。
Ad hoc⽹络凭借其基于IP的分组交换技术,可以提供⾼速率(现有的移动蜂窝⽹的传输速率不超过2Mbit/s,⽽Ad hoc⽹络在2~6GHz频段上可提供2~50Mbit/s的数据速率)的数据业务和多媒体业务,从⽽成为第三代全球移动通信系统的⼀个重要补充;另⼀⽅⾯,Ad hoc⽹络也可以作为Internet⽹络的⽆线延伸。
2 Ad hoc⽹络的特点Ad hoc⽹络的主要特征有以下⼏点:1)最⼩化的基础设施⽀持。
2)⾃组织和⾃管理。
既然⽹络基础结构是不具可⽤性的,这些节点必须通过⾃⼰组织和维护⽹络(要求有⾃主的分布式控制)。
节点能侦测到其它节点的存在,并和它们⼀起加⼊⽹络。
3)⼤部分甚⾄所有节点都在移动,导致⽹络拓扑动态变化。
当节点移动时,⽹络拓扑变化,新的节点加⼊,⼀些节点离开,或者是⼀些路由中断。
经常出现频繁的、临时的、突发性的⽹络连接损失。
4)⽆线链路。
既然⼤多数节点是移动的,那就意味着只能是⽆线通信⽅式。
5)节点既是⼀个主机,⼜是⼀个路由器。
⼀个节点可能想连接到超出单跳距离外的另⼀个节点,那么对每⼀个节点⽽⾔,路由功能是必需的,因为⽹络没有下部结构⽀持,节点不必是同⼀类型(可以是电话、PDA、膝上型电脑、传感器等)。
七年级下英语保护树木作文
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七年级下英语保护树木作文Preserving the Verdant Canopy: A Seventh-Grade Reflection on Protecting TreesTrees, the silent sentinels of our natural world, play a pivotal role in sustaining the delicate balance of our ecosystem. As we embark on our journey through the seventh grade, it is our responsibility to cultivate a deep appreciation for the intrinsic value of these magnificent living beings and take proactive steps to safeguard their well-being. In this essay, we shall delve into the importance of tree conservation and explore practical ways in which we can contribute to this noble cause.At the heart of the matter lies the undeniable truth that trees are the lungs of our planet, absorbing carbon dioxide and releasing life-giving oxygen. Their verdant foliage not only enhances the aesthetic beauty of our surroundings but also serves as a crucial habitat for a myriad of species, from the chirping birds to the scurrying insects. By preserving these arboreal sanctuaries, we ensure the continued flourishing of biodiversity, which is essential for the maintenance of a healthy and thriving ecosystem.Furthermore, trees play a pivotal role in regulating the climate and mitigating the effects of global warming. Their extensive root systems stabilize the soil, preventing erosion and reducing the risk of landslides. Additionally, the shade they provide can help lower the ambient temperature, thereby reducing the energy demands for cooling and contributing to more sustainable living practices.Beyond their environmental significance, trees also hold immense cultural and historical value. They have been revered in many ancient civilizations as symbols of life, wisdom, and resilience. Some trees, with their towering trunks and sprawling branches, have borne witness to the passing of generations, serving as silent guardians of our collective heritage. Preserving these living monuments not only honors our past but also inspires future generations to cultivate a deeper connection with the natural world.However, the unfortunate reality is that our forests and urban tree canopies are facing unprecedented threats due to factors such as deforestation, urbanization, and climate change. The loss of these precious resources has far-reaching consequences, including the disruption of delicate ecological balances, the displacement of wildlife, and the exacerbation of environmental challenges such as air pollution and flood risks.As seventh-grade students, we have the power to make a meaningfuldifference in the fight to protect our trees. One of the most important steps we can take is to raise awareness and educate our peers, families, and community about the importance of tree conservation. Through school-based initiatives, we can organize tree-planting events, participate in park clean-ups, and engage in discussions that highlight the environmental, social, and economic benefits of a thriving urban forest.Furthermore, we can advocate for policy changes and support local government initiatives that prioritize tree preservation and sustainable urban planning. By voicing our concerns and actively engaging with decision-makers, we can ensure that the protection of trees becomes a key priority in our community's development agenda.In our personal lives, we can also make small but impactful changes. We can choose to plant native tree species in our backyards, maintaining them with care and ensuring their long-term health. We can also support eco-friendly businesses and organizations that prioritize sustainable forestry practices and promote the responsible use of wood products.By embracing a holistic approach to tree conservation, we can create a ripple effect that inspires others to join the movement. As we grow and develop, our commitment to protecting the verdant canopy thatgraces our world will become a defining characteristic of our generation, a testament to our collective responsibility as stewards of the environment.In conclusion, the preservation of trees is not merely an ecological imperative but a moral obligation that we, as seventh-grade students, must embrace. By fostering a deep appreciation for the intrinsic value of these living giants and taking proactive steps to safeguard their well-being, we can secure a more sustainable and vibrant future for our planet. Let us be the generation that leaves an indelible mark on the world, not through the destruction of our forests, but through the nurturing and preservation of their verdant splendor.。
第八章 Routing Protocol
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192.168.1.0/24 New York 192.168.4.0/24 Tokyo 192.168.2.0/24 192.168.6.0/24 London 192.168.3.0/24
RIP协议度量值
RIP以到目的网络的跳数(Hop) 作为度量,可用跨越路由器个 数来计算 RIP最大度量值为15,16意味 着不可达,因此RIP网络适用 的网络规模较小
定时器
30s 停止更新 路由无效 路由刷新
有限路由更新
可以在某一接口配置,用来对指定的路由协议,指定的接口不传 送路由更新报文 如: Router rip Passive-Interface e0 Network 192.168.0.0 Network 192.168.1.0
RIP设计约束
D
C
B
G
E F
A
触发定时器(Update)
路由器定期更新的时间间隔,对于RIP协议来说为30秒 不总是确切的等于30秒,为了防止设备发送路由更新引起的 路由开销将最终引起设备改变路由更新时间到同步状态
无效定时器(Invalid)
用来探测网络介质故障,确定路由无效的时间 对于RIP来说Invalid Timer=180秒,即上次更新路由之后的180秒 后,如果没有收到指定网络的路由更新则认为路由无效 Invalid定时超时后,将向邻居路由器发送指定网络的不可达信息
New York
London
Tokyo 192.168.3.0/24
毒性逆转(Poison Reverse Update)
简单的水平分割(Split Horizon) 技术忽略了路由更新报文中在信 息获得方向上发送的路由信息 通过采用反向通告一个度量值 =16(无穷大)的路由到源端的 方法,可立即消除两相邻路由器 将可能发生的任何环路 这虽然增加了路由更新报文的大 小,但对防止路由环路很有帮助
物联网的核心技术-传感器网络幻灯片PPT
![物联网的核心技术-传感器网络幻灯片PPT](https://img.taocdn.com/s3/m/80fe8008998fcc22bdd10dbb.png)
成熟,集数据采集、处理,数据传输、
网络的突出特性是具备自组织能力。
通信等一体的无线传感器网络引起了 • 根据网络中节点是否可移动,无线Ad hoc
人们极大的重视。
网络又可分为两类(如图1): 一类为移
• 目前无线网络可分为两类:其一为有基 础设施网,需要有线连接的固定基站来
动Ad hoc网络(Mobile Ad hoc Network,简 称MANET),1997年IETF(网络工程任务组)
环境监测
© BLOVUE TOI LAB, All Rights Protected.
无线传感器网络典型应用
空中管制
FLOWERS BY HANDS FLOWERS IN EYES
海洋管制
© BLOVUE TOI LAB, All Rights Protected.
无线传感器网络典型应用
交通监控
无线传感器网络的特征与体系结构 与传统网络相比,传感器网络具有以下特征:
• 节点分布极其稠密且数目很大。 • 传感器网络中节点能量、存储空间及计算能力等资源非常有限,且能量资源等无法补
充。 • 在传感器网络中,传感节点在布置完毕后,除了少数节点需要移动以外,大部分节点
都是静止的。 • 多跳通信。由于低功率射频器件的信号传播范围有限,WSN 应该能支持多跳通信,下
• 物理层(Physical Layer) 无线通讯方式有射频(RF-radio frequency)和红外(IR-infrared)两种。由于红外方式的方向 性限制,使其应用更多的局限在点对点直接通讯,故无线传感器网络倾向于射频通讯。 在通迅频带使用上可参考免申请的ISM(Industrial Security Manual,工业安全手册)(工 业、科学和医疗)开放频段——2.4GHz(全球)、433MHz(欧洲)和917MHz(美国)。 当通讯网络工作在开放频带时也会受到其它外部系统的影响,使用时必须采取抗干扰 (微波炉、802.11b和蓝牙等设备)措施。
AD-HOC自组网路由协议
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中间节点维护动态路由表项
本地HELLO消息:用于决定本地连接
可以减少路由请求的响应时间 在必要时,可以触发更新
解决信息新鲜度问题 节点顺序号 广播IDAODV(1)
路由条目和序列号绑定
每个节点维护两个计数器
15
AODV(3)- 路由请求
当节点N想和节点M通信,但是没有到节点M的路由时,节点N 会发起对M的路由请求 节点N广播一个RREQ(Route Request)的报文给它的邻居 顺序号
LSDB A-B A-C
LSDB A-B
LSDB B-D A-C B-C
LSDB B-D
LSDB A-B A-C B-C C-D
B-C C-D
A
C
D
A
C
D
B
LSDB A-B B-C
B
LSDB
LSA from D
A-B B-C A-C C-D
hello
LSA from C
10
AD-HOC路由 VS. 传统路由
应用场景
军事,比如一个小分队偏远地区/无人区/敌区实施任务 救灾,通信基础设施被破坏,营救团队之间的通信 传感器网络,没有通信基础设施 智慧家庭
BTS Backhau BSC l
Network Core MSC Netwo rk 3
AD-HOC网络简介(2)- 标准化情况
Wifi MESH over 802.11 (802.11s)
OLSR:优化的链路状态路由协议
Performance: AODV vs OLSR
AD-HOC网络简介(1)- 为啥需要AD-HOC
Cisco Nexus 3048交换机数据手册说明书
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Data SheetCisco Nexus 3048 SwitchProduct OverviewThe Cisco Nexus® 3048 Switch (Figure 1) is a line-rate Gigabit Ethernet top-of-rack (ToR) switch and is part of the Cisco Nexus 3000 Series Switches portfolio. The Cisco Nexus 3048, with its compact one-rack-unit (1RU) form factor and integrated Layer 2 and 3 switching, complements the existing Cisco Nexus family of switches. This switch runs the industry-leading Cisco® NX-OS Software operating system, providing customers with robust features and functions that are deployed in thousands of data centers worldwide. The Cisco Nexus 3048 is ideal for big data customers that require a Gigabit Ethernet ToR switch with local switching that connects transparently to upstream Cisco Nexus switches, providing an end-to-end Cisco Nexus fabric in their data centers. This switch supports both forward and reversed airflow schemes with AC and DC power inputs.Figure 1. Cisco Nexus 3048 SwitchMain BenefitsThe Cisco Nexus 3048 provides the following main benefits:●Wire-rate Layer 2 and 3 switching◦Layer 2 and 3 switching of up to 176 Gigabit per second (Gbps) and more than 132 million packets per second (mpps) in a compact 1RU form-factor switch●Robust and purpose-built Cisco NX-OS operating system for end-to-end Cisco Nexus fabric◦Transparent integration with the Cisco Nexus family of switches to provide a consistent end-to-end Cisco Nexus fabric◦Modular operating system built for resiliency◦Integration with Cisco Data Center Network Manager (DCNM) and XML management tools●Comprehensive feature set and innovations for next-generation data centers◦Virtual PortChannel (vPC) provides Layer 2 multipathing through the elimination of Spanning Tree Protocol and enables fully utilized bisectional bandwidth and simplified Layer 2 logical topologies without the need to change the existing management and deployment models.◦Power On Auto Provisioning (POAP) enables touchless bootup and configuration of the switch, drastically reducing provisioning time.◦Cisco Embedded Event Manager (EEM) and Python scripting enable automation and remote operations in the data center.◦Advanced buffer monitoring reports real-time buffer utilization per port and per queue, which allows organizations to monitor traffic bursts and application traffic patterns.◦The 64-way equal-cost multipath (ECMP) routing enables Layer 3 fat tree designs and allows organizations to prevent network bottlenecks, increase resiliency, and add capacity with little networkdisruption.◦EtherAnalyzer is a built-in packet analyzer for monitoring and troubleshooting control-plane traffic and is based on the popular Wireshark open source network protocol analyzer.◦Precision Time Protocol (PTP; IEEE 1588) provides accurate clock synchronization and improved data correlation with network captures and system events.◦Full Layer 3 unicast and multicast routing protocol suites are supported, including Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), Enhanced Interior Gateway Routing Protocol(EIGRP), Routing Information Protocol Version 2 (RIPv2), Protocol Independent Multicast sparse mode (PIM-SM), Source-Specific Multicast (SSM), and Multicast Source Discovery Protocol (MSDP).●Network traffic monitoring with Cisco Nexus Data Broker◦Build simple, scalable and cost-effective network tap or Cisco Switched Port Analyzer (SPAN) aggregation for network traffic monitoring and analysis.Configuration●48 fixed 10/100/1000-Mbps Ethernet ports● 4 fixed Enhanced Small Form-Factor Pluggable (SFP+) ports●Locator LED●Dual redundant power supplies●Fan tray with redundant fans●Two 10/100/1000-Mbps management ports●One RS-232 serial console port●One USB port●Locator LED and buttonSupport for both forward (port-side exhaust) and reversed (port-side intake) airflow schemes is available.Transceiver and Cabling OptionsFor uplink connectivity, the Cisco Nexus 3048 supports SFP+ direct-attach 10 Gigabit Ethernet copper, an innovative solution that integrates transceivers with Twinax cables into an energy-efficient and low-cost solution. For longer cable runs, multimode and single-mode optical SFP+ transceivers are supported. Table 1 lists the supported 10 Gigabit Ethernet transceiver options.Table 1. Cisco Nexus 3048 10 Gigabit Transceiver Support MatrixFor more information about the transceiver types, see/en/US/products/hw/modules/ps5455/prod_module_series_home.html.Cisco NX-OS Software OverviewCisco NX-OS is a data center-class operating system built with modularity, resiliency, and serviceability at its foundation. Cisco NX-OS helps ensure continuous availability and sets the standard for mission-critical data center environments. The self-healing and highly modular design of Cisco NX-OS makes zero-impact operations a reality and enables exceptional operation flexibility.Focused on the requirements of the data center, Cisco NX-OS provides a robust and comprehensive feature set that meets the networking requirements of present and future data centers. With an XML interface and a command-line interface (CLI) like that of Cisco IOS® Software, Cisco NX-OS provides state-of-the-art implementations of relevant networking standards as well as a variety of true data center-class Cisco innovations.Cisco NX-OS Software BenefitsTable 2 summarizes the benefits that Cisco NX-OS offers.Table 2. Benefits of Cisco NX-OS SoftwareCommon software throughout the data center: Cisco NX-OS runs on all Cisco data center switch platforms: Cisco Nexus 7000, 5000, 4000, 3000, 2000, and 1000V Series. ●Simplification of data center operating environment●End-to-end Cisco Nexus and Cisco NX-OS fabric ●No retraining necessary for data center engineering and operations teamsSoftware compatibility: Cisco NX-OS interoperates with Cisco products running any variant of Cisco IOS Software and also with any networking OS that conforms to the networking standards listed as supported in this data sheet. ●Transparent operation with existing network infrastructure●Open standards●No compatibility concernsModular software design: Cisco NX-OS is designed to support distributed multithreaded processing. Cisco NX-OS modular processes are instantiated on demand, each in a separate protected memory space. Thus, processes are started and system resources allocated only when a feature is enabled. The modular processes are governed by a real-time preemptive scheduler that helps ensure timely processing of critical functions. ●Robust software●Fault tolerance●Increased scalability●Increased network availabilityTroubleshooting and diagnostics: Cisco NX-OS is built with unique serviceability functions to enable network operators to take early action based on network trends and events, enhancing network planning and improving network operations center (NOC) and vendor response times. Cisco Smart Call Home and Cisco Online Health Management System (OHMS) are some of the features that enhance the serviceability of Cisco NX-OS. ●Quick problem isolation and resolution●Continuous system monitoring and proactive notifications●Improved productivity of operations teamsEase of management: Cisco NX-OS provides a programmatic XML interface based on the NETCONF industry standard. The Cisco NX-OS XML interface provides a consistent API for devices. Cisco NX-OS also supports Simple Network Management Protocol (SNMP) Versions 1, 2, and 3 MIBs. ●Rapid development and creation of tools for enhanced management●Comprehensive SNMP MIB support for efficient remote monitoringUsing the Cisco Nexus Data Broker software and Cisco Plug-in for OpenFlow agent, the Cisco Nexus 3048 Switch can be used to build a scalable, cost-effective, and programmable tap or SPAN aggregation infrastructure. This approach replaces the traditional purpose-built matrix switches with these switches. You can interconnect these switches to build a multilayer topology for tap or SPAN aggregation infrastructure. ●Scalable and cost effective●Robust traffic filtering capabilities●Traffic aggregation from multiple input ports across different switches●Traffic replication and forwarding to multiple monitoring toolsRole-based access control (RBAC): With RBAC, Cisco NX-OS enables administrators to limit access to switch operations by assigning roles to users. Administrators can customize access and restrict it to the users who require it. ●Tight access control mechanism based on user roles●Improved network device security●Reduction in network problems arising from human errorsCisco NX-OS Software Packages for Cisco Nexus 3048The Cisco NX-OS Software package for the Cisco Nexus 3048 offers flexibility and a comprehensive feature set along with consistency with Cisco Nexus access switches. The default system software has a comprehensive Layer 2 feature set with extensive security and management features. To enable Layer 3 IP unicast and multicast routing functions, additional licenses need to be installed. Table 3 lists the software licensing details.Table 3. Cisco NX-OS Software Package in the Cisco Nexus 3048* The Base license (N3K-C3048-BAS1K9) is required to take advantage of LAN Enterprise license (N3K-C3048-LAN1K9) features. Table 5 later in this document provides a complete feature list.Cisco Data Center Network ManagerThe Cisco Nexus 3048 is supported in Cisco DCNM. Cisco DCNM is designed for hardware platforms enabled for Cisco NX-OS, which consist of the Cisco Nexus Family of products. Cisco DCNM is a Cisco management solution that increases overall data center infrastructure uptime and reliability, hence improving business continuity. Focused on the management requirements of the data center network, Cisco DCNM provides a robust framework and comprehensive feature set that meets the routing, switching, and storage administration needs of present and future data centers. In particular, Cisco DCNM automates the provisioning process, proactively monitors the LAN by detecting performance degradation, secures the network, and streamlines the diagnosis of dysfunctional network elements.Cisco Nexus Data BrokerThe Cisco Nexus 3048 Switch with Cisco Nexus Data Broker can be used to build a scalable and cost-effective traffic monitoring infrastructure using network taps and SPAN. This approach replaces the traditional purpose-built matrix switches with one or more OpenFlow-enabled Cisco Nexus switches. You can interconnect these switches to build a scalable tap or SPAN aggregation infrastructure. You also can combine tap and SPAN sources to bring the copy of the production traffic to this tap or SPAN aggregation infrastructure. In addition, you can distribute these sources and traffic monitoring and analysis tools across multiple Cisco Nexus switches. For more details, visit /go/nexusdatabroker.Product SpecificationsTable 4 lists the specifications for the Cisco Nexus 3048, Table 5 lists software features, and Table 6 lists management standards and support.Table 4. Specifications* Please refer to Cisco Nexus 3000 Series Verified Scalability Guide for scalability numbers validated for specific software releases: /en/US/products/ps11541/products_installation_and_configuration_guides_list.html.Table 5. Software FeaturesPort-based CoS assignmentModular QoS CLI (MQC) complianceACL-based QoS classification (Layers 2, 3, and 4)MQC CoS markingDifferentiated services code point (DSCP) markingWeighted Random Early Detection (WRED)CoS-based egress queuingEgress strict-priority queuingEgress port-based scheduling: Weighted Round-Robin (WRR)Explicit Congestion Notification (ECN)Security ●Ingress ACLs (standard and extended) on Ethernet●Standard and extended Layer 3 to 4 ACLs: IPv4, Internet Control Message Protocol (ICMP), TCP, UserDatagram Protocol (UDP), etc.●VLAN-based ACLs (VACLs)●Port-based ACLs (PACLs)●Named ACLs●ACLs on virtual terminals (vtys)●DHCP snooping with Option 82●Port number in DHCP Option 82●DHCP relay●Dynamic Address Resolution Protocol (ARP) inspection●CoPPCisco Nexus Data Broker ●Topology support for tap and SPAN aggregation●Support for QinQ to tag input source tap and SPAN ports●Traffic load balancing to multiple monitoring tools●Traffic filtering based on Layer 1 through Layer 4 header information●Traffic replication and forwarding to multiple monitoring tools●Robust RBAC●Northbound Representational State Transfer (REST) API for all programmability support Management ●Switch management using 10/100/1000-Mbps management or console ports●CLI-based console to provide detailed out-of-band management●In-band switch management●Locator and beacon LEDs●Port-based locator and beacon LEDs●Configuration rollback●SSHv2●Telnet●AAA●AAA with RBAC●RADIUS●TACACS+●Syslog●Syslog generation on system resources (for example, FIB tables)●Embedded packet analyzer●SNMP v1, v2, and v3●Enhanced SNMP MIB support●XML (NETCONF) support●Remote monitoring (RMON)●Advanced Encryption Standard (AES) for management traffic●Unified username and passwords across CLI and SNMP●Microsoft Challenge Handshake Authentication Protocol (MS-CHAP)●Digital certificates for management between switch and RADIUS server●Cisco Discovery Protocol Versions 1 and 2●RBAC●Cisco Switched Port Analyzer (SPAN) on physical, PortChannel and VLAN interfacesTable 6. Management and Standards Support Description SpecificationMIB support Generic MIBs●SNMPv2-SMI●CISCO-SMI●SNMPv2-TM●SNMPv2-TC●IANA-ADDRESS-FAMILY-NUMBERS-MIB●IANAifType-MIB●IANAiprouteprotocol-MIB●HCNUM-TC●CISCO-TC●SNMPv2-MIB●SNMP-COMMUNITY-MIB●SNMP-FRAMEWORK-MIB●SNMP-NOTIFICATION-MIB●SNMP-TARGET-MIB●SNMP-USER-BASED-SM-MIB●SNMP-VIEW-BASED-ACM-MIB●CISCO-SNMP-VACM-EXT-MIBEthernet MIBs●CISCO-VLAN-MEMBERSHIP-MIB●LLDP-MIB●IP-MULTICAST-MIBConfiguration MIBs●ENTITY-MIB●IF-MIB●CISCO-ENTITY-EXT-MIB●CISCO-ENTITY-FRU-CONTROL-MIB●CISCO-ENTITY-SENSOR-MIB●CISCO-SYSTEM-MIB●CISCO-SYSTEM-EXT-MIB●CISCO-IP-IF-MIB●CISCO-IF-EXTENSION-MIB●CISCO-NTP-MIB●CISCO-IMAGE-MIB●CISCO-IMAGE-UPGRADE-MIB Monitoring MIBs●NOTIFICATION-LOG-MIB●CISCO-SYSLOG-EXT-MIB●CISCO-PROCESS-MIB●RMON-MIB●CISCO-RMON-CONFIG-MIB●CISCO-HC-ALARM-MIBSecurity MIBs●CISCO-AAA-SERVER-MIB●CISCO-AAA-SERVER-EXT-MIB ●CISCO-COMMON-ROLES-MIB●CISCO-COMMON-MGMT-MIB●CISCO-SECURE-SHELL-MIB Miscellaneous MIBs●CISCO-LICENSE-MGR-MIB●CISCO-FEATURE-CONTROL-MIB ●CISCO-CDP-MIB●CISCO-RF-MIBLayer 3 and Routing MIBs●UDP-MIB●TCP-MIB●OSPF-MIB●BGP4-MIB●CISCO-HSRP-MIBStandards ●IEEE 802.1D: Spanning Tree Protocol●IEEE 802.1p: CoS Prioritization●IEEE 802.1Q: VLAN Tagging●IEEE 802.1s: Multiple VLAN Instances of Spanning Tree Protocol●IEEE 802.1w: Rapid Reconfiguration of Spanning Tree Protocol●IEEE 802.3z: Gigabit Ethernet●IEEE 802.3ad: Link Aggregation Control Protocol (LACP)●IEEE 802.3ae: 10 Gigabit Ethernet●IEEE 802.1ab: LLDP●IEEE 1588-2008: Precision Time Protocol (Boundary Clock)RFC BGP●RFC 1997: BGP Communities Attribute●RFC 2385: Protection of BGP Sessions with the TCP MD5 Signature Option●RFC 2439: BGP Route Flap Damping●RFC 2519: A Framework for Inter-Domain Route Aggregation●RFC 2545: Use of BGPv4 Multiprotocol Extensions●RFC 2858: Multiprotocol Extensions for BGPv4●RFC 3065: Autonomous System Confederations for BGP●RFC 3392: Capabilities Advertisement with BGPv4●RFC 4271: BGPv4●RFC 4273: BGPv4 MIB: Definitions of Managed Objects for BGPv4●RFC 4456: BGP Route Reflection●RFC 4486: Subcodes for BGP Cease Notification Message●RFC 4724: Graceful Restart Mechanism for BGP●RFC 4893: BGP Support for Four-Octet AS Number SpaceOSPF●RFC 2328: OSPF Version 2●8431RFC 3101: OSPF Not-So-Stubby-Area (NSSA) Option●RFC 3137: OSPF Stub Router Advertisement●RFC 3509: Alternative Implementations of OSPF Area Border Routers●RFC 3623: Graceful OSPF Restart●RFC 4750: OSPF Version 2 MIBRIP●RFC 1724: RIPv2 MIB Extension●RFC 2082: RIPv2 MD5 Authentication●RFC 2453: RIP Version 2●IP Services●RFC 768: User Datagram Protocol (UDP)●RFC 783: Trivial File Transfer Protocol (TFTP)●RFC 791: IP●RFC 792: Internet Control Message Protocol (ICMP)●RFC 793: TCP●RFC 826: ARP●RFC 854: Telnet●RFC 959: FTP●RFC 1027: Proxy ARP●RFC 1305: Network Time Protocol (NTP) Version 3●RFC 1519: Classless Interdomain Routing (CIDR)●RFC 1542: BootP Relay●RFC 1591: Domain Name System (DNS) Client●RFC 1812: IPv4 Routers●RFC 2131: DHCP Helper●RFC 2338: VRRPIP Multicast●RFC 2236: Internet Group Management Protocol, version 2●RFC 3376: Internet Group Management Protocol, Version 3●RFC 3446: Anycast Rendezvous Point Mechanism Using PIM and MSDP●RFC 3569: An Overview of SSM●RFC 3618: Multicast Source Discovery Protocol (MSDP)●RFC 4601: Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)●RFC 4607: Source-Specific Multicast for IP●RFC 4610: Anycast-RP using PIM●RFC 5132: IP Multicast MIBSoftware RequirementsCisco Nexus 3000 Series Switches are supported by Cisco NX-OS Software Release 5.0 and later. Cisco NX-OS interoperates with any networking OS, including Cisco IOS Software, that conforms to the networking standards mentioned in this data sheet.Regulatory Standards ComplianceTable 7 summarizes regulatory standards compliance for the Cisco Nexus 3000 Series.Table 7. Regulatory Standards Compliance: Safety and EMCOrdering InformationTable 8 provides ordering information for the Cisco Nexus 3048.Table 8. Ordering InformationService and SupportCisco offers a wide range of services to help accelerate your success in deploying and optimizing the Cisco Nexus 3000 Series in your data center. The innovative Cisco Services offerings are delivered through a unique combination of people, processes, tools, and partners and are focused on helping you increase operation efficiency and improve your data center network. Cisco Advanced Services uses an architecture-led approach to help you align your data center infrastructure with your business goals and achieve long-term value. Cisco SMARTnet®Service helps you resolve mission-critical problems with direct access at any time to Cisco network experts and award-winning resources. With this service, you can take advantage of the Cisco Smart Call Home service capability, which offers proactive diagnostics and real-time alerts on your Cisco Nexus 3000 Series Switches. Spanning the entire network lifecycle, Cisco Services helps increase investment protection, optimize network operations, support migration operations, and strengthen your IT expertise.For More InformationFor more information, please visit /go/nexus3000. For information about Cisco Nexus Data Broker, please visit /go/nexusdatabroker.Printed in USA C78-685363-0510/14。
Research Summary
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Research SummarySandeep K.S.Gupta1Research Accomplishments in Wireless Networks and Mobile Computing The combination of wireless communication infrastructure and portable computing devices has laid the foundation for a new network computing paradigm,called mobile computing,which permits access to information and collaboration with others while on the move[30].Wireless mobile networks are characterized by severe constraints on resources, such as bandwidth and battery power,and by rapidfluctuations in availability of these resources;this makes it difficult for the system software to provide guaranteed quality-of-service at levels required by many distributed and collabora-tive applications.Further,mobility adds a new dimension to the distributed computing paradigm which has implications for specification,design,verification,and implementation of both system and application software[41].A challeng-ing issue is to determine the interface and the guarantees that system software can efficiently provide to developers of both location-independent and location-dependent(context-aware)[47]applications on mobile networks[42].This has resulted in research on adaptive applications and system software which can gracefully respond to changes in oper-ating conditions[4].My current research is focused on developing adaptive solutions for resource allocation,location management,unicast and multicast routing protocols and caching schemes in wireless networks for supporting mobile computing.1.1Adaptive Unicast and Multicast Protocols for Mobile Ad Hoc NetworksA mobile ad hoc network consists of mobile computing devices with radio transmission and reception capability.Two node are neighbors in the network and can communicate directly when they are within transmission range of each other and radio propagation condition in the vicinity of these nodes is munication between non-neighboring nodes requires a multi-hop routing protocol.Although mobile ad hoc networks have been mainly used in military ap-plications,they are being increasingly used for civilian applications such as virtual class rooms,wireless local area networks,and law enforcement.It is predicted that in the future such ad hoc networks in collaboration with cellular and overlay networks will provide a ubiquitous computing environment[56].Design and development of commu-nication support for distributed and collaborative applications on mobile ad hoc networks is the current emphasis of my research.The motivation for this work stems from the challenges mobile ad hoc networks pose for supporting the reliable and efficient communication services necessary for distributed computing[43,24].Mobile ad hoc networks present a different network model from the ones used for traditional communication protocol design and implementa-tion.The topology of the network changes with node movements,variations in the radio propagation conditions,and depletion of battery power of the nodes.The rate of topological changes can be different at different times,as well as in different regions of the network.The network can experience frequent network partitioning and may require reconfig-uration of partitioned subnetworks.Moreover,radio bandwidth is a comparatively precious resource and needs to be conserved.Since this dynamic network model is considerably different from that of the current static network model used for developing communication protocols,it is necessary to investigate the appropriateness of existing protocols and develop efficient,reliable,and scalable collective communication protocols for mobile ad hoc networks.In our work,we have defined a mobility-tolerant communication protocol[26]to be one which can function cor-rectly in the presence of transient failures due to mobility of hosts in the network.Development of efficient and scalable mobility-tolerant protocols for group communication is one of my major research thrust.The goal is to develop group communication protocols for one-to-many and many-to-many interaction patterns which adapt to the rate of change of mobility,distribution(spread)and size of the group,and size of the network.We are developing efficient protocolswhich maintain minimal state information,use a minimal number of control messages,react to topological changes only when necessary,and localize the reaction to the neighborhood of the topology change.We aim to provide solutions to the following questions:What guarantees/interface group communication services on mobile ad hoc networks should provide to the tra-ditional and emerging distributed and collaborative applications?How can these group communication services be efficiently implemented in a mobility-tolerant manner on mo-bile ad hoc networks using the underlying point-to-point(unicast)routing and data link layer support?How to characterize the performance of a mobility-tolerant protocol through analysis and simulation?1.1.1Adaptive Protocol for Reliable Multicast[24,28]In this work,we have developed a multicast protocol which combines the advantages of multicast protocol presented by Gerla et.al[5]and by Pagani and Rossi[43].This protocol uses core-based tree(CBT)and incorporates mechanisms for gluing together fragments of this tree when it gets fragmented due to movement of A graph-theoretic notion of for-warding region is introduced which is used to glue together fragments of a multicast trees.The gluing process involves flooding of the forwarding region of only those nodes that witness topology change due to node mobility.Delivery of multicast messages to mobile nodes is expedited through(i)pushing of the message by witness nodes in their forward-ing regions and(ii)pulling of messages by a mobile node during(re)joining process.Hence,the protocol conserves network bandwidth by using a combination of the push-pull approach and by restrictingflooding only to the essential parts of the network that is affected by topology change.We have developed a theoretical model to compute the proba-bility of packet loss(as a function of the mobility rate)for our proposed scheme compared to the the CBT protocol;we have also evaluated the effectiveness of forwarding regions as compared to traditionalflooding.Our analysis shows that the proposed scheme significantly outperforms CBT.1.1.2Self-Stabilizing Multicast Communication Protocols[27,26,7]We are currently applying the paradigm of self-stabilization in distributed fault tolerant algorithm design to tackle the problem of topology change in mobile networks.Self-stabilizing distributed algorithms converge to a global legiti-mate state in presence of any number of intermittent faults while using only local knowledge for actions at each node. Hence,self-stabilizing protocols provide means for tolerating transient faults.However,self-stabilizing protocols pro-vide a non-masking approach to fault tolerance.The service provided by a self-stabilizing protocol may be unavailable while it is stabilizing.Further,the self-stabilizing protocols only guarantee that the protocol will eventually stabilize. Hence,providing no guarantee on how soon the service will become available after the occurrence of faults.These two features of self-stabilizing protocols present many interesting challenges in employing self-stabilizing protocols in mobile ad hoc networks;some of which are i)how can the self-stabilizing protocols be enhanced so that the service remains available while the multi-cast tree is being adapted to the new topology?and ii)how can the self-stabilization protocol be triggered in a controlled manner so as to not overwhelm the system in presence of high mobility?Efficient solutions for performing multi-casting in mobile ad hoc networks will rely on what support underlying data link layer can provide and how the network layer multi-cast protocol can exploit these facilities to intelligently control the overheads while providing desirable QoS.Our goal is to take a synergistic approach in designing the multi-cast protocols so as to make them compatible with the underlying networking layers.In our preliminary work,we have adapted two self-stabilizing protocol for maintaining multicast tree in a mobile ad hoc networks.Thefirst is based on pruning and rooting a minimum spanning tree[27,26]and the other one is based on pruning and rooting a shortest-path tree[7].This work is supported by a grant from NSF.Under this grant we will develop adaptive multi-cast protocols for mobile ad hoc networks with different performance/cost tradeoffs.1.1.3Witness-Aided Routing(WAR)Protocol[1,2]Host mobility and higher link instability are the most prominent factors which affect the performance of routing pro-tocols for ad hoc networks.Unlike proactive protocols,which attempt to reduce the effect of mobility by periodically upgrading routing information(at the expense of network resources),reactive-style protocols are more prone to routingfailures due to the lack of up to date information about network topology.Furthermore,end-to-end guarantees are more difficult to obtain as the network size increases,which hints that end-to-end error recovery may not be a feasible idea for large networks.Further,mobile ad hoc networks may exhibit unidirectional links due to the nature of wireless com-munication.Presence of unidirectional links interferes with the controlflow of many existing unicast routing protocols for such networks,which adversely effects their performance and limits their applicability.We have developed a new protocol designed to support unicast routing over both bidirectional and unidirectional links in ad hoc networks.The WAR(Witness-Aided Routing)protocol is a reactive routing protocol.It is based on the concept of witness host,whose role is to help in bypassing a unidirectional or a failed link along the path.Hence,WAR uses local error recovery as opposed to end-to-end error recovery used by other reactive protocol such as Dynamic Source Routing(DSR)protocol.We have analytically compared the effect of local error recovery vs.end-to-end error recovery in reactive protocols.Our results show that the performance of DSR degrades extremely fast as the route length increases(that is,DSR is not scalable),while WAR maintains both low latency and low resource consumption regardless of the route length.1.2Adaptive Channel Allocation for Wireless Networks[25,29,31]A problem related to efficiently performing communication in mobile networks is the problem of channel(bandwidth) allocation.Channel allocation is needed for supporting connection-oriented traffic.Along with Pradip Srimani,I have developed a distributed and dynamic channel allocation techniques which combines the previously known basic search and basic update scheme[25,29].We have developed another channel allocation scheme[31].This scheme combines the static and dynamic scheme to further minimize the channel allocation time as well as maintain the advantage of dis-tributed dynamic allocation.In this scheme,each node(cell)in the system continually monitors its own load(rate of request of channels)and switches back and forth between static(fixed channel allocation scheme)and dynamic(search-based or update-based)modes of allocation depending upon threshold values of loads.The threshold values are used tofine-tune the overall system performance.Each node adapts to its own load independent of other nodes in its inter-ference region.1.3Adaptive Location Management[53,54]Location management is an essential service in mobile networks.It provides mechanisms for recording and querying location of mobile units in the network.This is needed for establishing calls or delivering messages to mobile units.In personal communication service(PCS)networks,location management protocols such as IS-41and GSM use statically defined Registration Areas(RAs).Each RA consists of all the communication cells in its geographical area.Associ-ated with each RA is a database called Location Registrar.Further,each mobile unit has a pre-assigned Home Location Registrar(HLR).A mobile unit informs its location(location update operation)whenever it moves from one communi-cation cell to another.When the move results in move from one registration area to another updates are made to home location registrar.In order to locate a mobile unit the initiator of the call or(sender of the message)first contacts the HLR of the destination mobile unit to know its current location(registration area).Location Management based on statically defined registration areas is unable to adapt to changing mobility and call patterns of the users.We developed an extension to PCS location management protocol which uses dynamically overlapped registration areas.Overlapping of registration areas helps in reducing the number of location updates for afixed mobility pattern. Further,dynamically changing the registration area is used to adapt to changes in aggregate mobility and call pattern. This reduces and balances the signaling and database access load on the mobile services stations(MSS).In order to study the adaptiveness of the proposed scheme,we have simulated our scheme under various mobility and call patterns. Our simulation results show that by dynamically adapting the registration areas to aggregate mobility and call pattern of the mobile units is useful when the mobility pattern exhibit locality.For such mobility and call patterns,the proposed scheme can greatly reduce the average signaling and database access load on MSSs.Further,the cost of adapting the registration areas is shown to be low in terms of memory and communication requirements.1.4Efficient Cache Management Scheme[32,33]Caching data at the mobile hosts(MHs)in a wireless network helps alleviate problems associated with slow,limited bandwidth wireless links,by reducing latency and conserving bandwidth.Battery power is conserved by reducing the number of up-link requests.A mobile computing environment is a distributed system,thus when data at the server changes,the client hosts must be made aware of this fact in order for them to invalidate their cache otherwise the host would continue to answer queries with the cached values returning incorrect data.The nature of the physical medium coupled with the fact that disconnections from the network are very frequent in mobile computing environments de-mand a cache invalidation strategy with minimum possible overheads.We have developed a new cache maintenance scheme,called AS.The objective of the proposed scheme is to min-imize the overhead for the MHs to validate their cache upon reconnection,to allow stateless servers,and to minimize the bandwidth requirement.The general approach is i)to use asynchronous invalidation messages,and ii)to buffer invalidation messages from servers at the MH’s Home Location Cache(HLC)while the MH is disconnected from the network and re-deliver these invalidation messages to the MH when it gets reconnected to the e of asyn-chronous invalidation messages minimizes access latency,buffering of invalidation messages minimizes the overhead of validating MH’s cache after each disconnection and use of HLC off-loads the overhead of maintaining state of MH’s cache from the servers.The MH can be disconnected from the server either voluntarily(e.g.switching off the laptop) or involuntarily(e.g.wireless link failure,handoff delay);we capture the effects of both by using a single parameter s:the percentage of time a mobile host is disconnected from the network.We have demonstrated the efficiency of our scheme through simulation and performance modeling.In particular, we have shown that the average data access latency and the number of up-link requests by a MH decrease by using the proposed strategy at the cost of using buffer space at the HLC.We have compared our AS scheme with other caching schemes such as Barbara and Imilienski’s TS and AT scheme[3]in terms of performance metrics like latency,number of up-link requests etc.under both high and low rate of change of data at servers for various values of the parameter. We have also developed a mathematical model for the scheme which matches closely with the simulation results. 1.5Performance Evaluation of IEEE802.11MAC Protocol[35,36]With the standardization of IEEE802.11Wireless Local Area Network(WLAN)protocol specification,WLANs are becoming increasingly popular.The problem of hidden terminals in presence of obstacles and client mobility is unique to wireless networks and it is essential to study their effects on network performance.In this paper we investigate the performance of IEEE802.11wireless local area network(WLAN)protocol in the presence of mobile and hidden terminals.In order to study the joint effect of hidden terminals and user mobility on the performance of IEEE802.11 DCF,we have extended Tobagi and Kleinrock’s[48]hearing graph framework to model hidden terminals in a static environment.We derive a combined mobility and hidden terminal model using a Markov chain from the hearing graph of a given physical layout.The simple model uses two parameters:,which controls the number of hidden terminals in the steady state,and,which controls the rate of mobility of each terminal.By varying the values of and we can systematically generate scenario with different number of hidden terminals and different mobility rates for a particular physical layout with static obstructions.We have developed a discrete event simulator which uses the parameterized model to obtain the throughput and blocking probability behavior of an IEEE802.11based ad hoc network in the presence of certain static obstructions. Our simulations suggest that the IEEE802.11protocol is robust enough to handle moderate conditions of hidden termi-nals and mobility,but the performance may degrade under extreme conditions.Carefully selecting protocol parameters (RTS and Fragmentation Threshold)can help improve the performance even under extreme conditions.2Other Research Accomplishments2.1SSA-based Flow-Sensitive Type Analysis Technique for Object-Oriented Programs[37,38]An important step in compile-time optimization of object-oriented languages with polymorphic and virtual functions is static determination of concrete types(classes)of variables referring to objects.This information is essential for iden-tifying monomorphic call sites and hence opening opportunities for interprocedural optimizations.We have developed an SSA based interprocedural static type analysis algorithm,which combines constant propagation and type propaga-tion.This algorithm enhances Wegman and Zadeck’s[55]sparse conditional constant propagation(SCC)algorithm to perform simultaneous type analysis on a modified-SSA representation of a object-oriented program.Due to synergy between constant and types propagation,the proposed algorithm detects more constants and provides more precise type information than the case wherein the two analysis are performed separately.The worst-case behavior of this algorithm is polynomial in the number of classes declared in the program.To show empirically that our algorithm can improve the run-time performance of object-oriented programs,we have performed some experimental tests using Bench++ benchmark tool from AT&T Research Labs.These tests have shown that combined type and constant propagation is beneficial in codes with control dependent instantiations.2.2Optimizing Object-Oriented Programs for EPIC Architectures[44,45,46]The direct costs of virtual function calls in object-oriented programs is a runtime overhead incurred by the number of operations required to compute a target function address and the time to perform these operations.We have been look-ing into ways of exploiting EPIC technology to benefit object-oriented programs.This research has primarily focused on virtual function calls,and how their costs can be reduced by use of EPIC features.A number of innovative ways have been proposed that transform the dynamic dispatch sequence of a virtual function call into a stream-lined virtual function call,or into a statically-bound function call.These transformations rely on static analysis techniques such as type and constant propagation or class hierarchy analysis,along with front-end optimizations such as statically-binding virtual function calls that are monomorphic or with runtime class testing,and then using back-end optimizations that utilize control speculation,data speculation,predication and an exposed memory hierarchy.In particular we have developed two techniques:i)Predicated VFT Loading and ii)Predicated Class Testing that use an Explicit Parallel Instruction Computing(EPIC)architectural feature known as predication,to reduce the direct cost of virtual function calls.These techniques employ predication to conditionally perform cost-saving transforma-tions to the original dispatch sequence of a virtual function call in order to reduce the memory latency associated with these calls,or to transform the virtual function calls into statically-bound function calls.Predicated VFT loading is based on the possibility that the same virtual function table(VFT)will be shared between several virtual function calls, and whereby exploits this possibility by interleaving the function calls for objects whose types cannot be determined statically.Runtime class testing is a technique whereby virtual function calls are transformed into statically-bound function calls through a series of conditional branches.Through this transformation,the overhead of virtual function calls can be significantly reduced.However,the drawback of these tests is that by relying on conditional branches,the amount of instruction-level parallelism(ILP)is limited and the mispredict penalties can be relatively high.Predicated class testing improves the benefits of class testing by eliminating these drawbacks of runtime class testing.By use of the Trimaran research tool and analytical cost models,this research has successfully shown the quantitative benefits of applying EPIC technology towards object-oriented programs.This research has been performed in conjunction with the VLSI Technology Center at Hewlett-Packard.2.3Compilation and Program SynthesisMy early work was on compilation and synthesis of programs for distributed memory machines[13,12,8,9,14,10, 15,11].One of the goal of this project was to develop a tool for designing efficient algorithms for computing Fouriertransforms on different parallel machines.In this project,I worked with my Ph.D.advisors Prof.C.-H.Huang and Prof.P.Sadayappan(from Ohio State University),Prof.R.W.Johnson(from St.Cloud State University),and some other graduate students.This work resulted in a parallel programming tool called EXTENT(EXpert system for TENsor product Translation)[6].My contribution to this project was to develop program synthesis techniques for distributed-memory machines from a mathematical representation of the computation.The mathematical representation consisted of tensor product and other matrix operations.We looked at two approaches to program synthesis:i)using point-to-point communication and ii)using data redistributions.The problem of efficiently performing data redistribution is a specific case of a more general problem of how to generate communication-efficient code for array expressions in-volving distributed arrays.This problem arises in compilation of programs expressed in languages such as HPF(High-Performance Fortran).We developed compilation schemes for efficient execution of array expressions on distributed-memory machines[16,17,15].After completing my Ph.D.at Ohio State University in1995,I continued working on the problem of program synthesis as a Post Doctoral student under the guidance of Professor Reif at Duke University.Here I worked with Prof. Reif and his Ph.D.student,Zhiyong Li,on the problem of extending my Ph.D.work on synthesizing communication-efficient programs to synthesize I/O-efficient programs for parallel I/O system[20,39,40].In the fall of1995I joined Ohio University as a Visiting Assistant Professor.At Ohio University,I worked with Sudha Krishnamurthy,who was doing Masters under my supervision,on the problem of statically determining the data distributions which are suitable for global array in an HPF-like program.We developed an interprocedural technique which extended the work by Kennedy and Kremer[34]on intra-procedural data distribution analysis[18,19].2.4Collective Communication on K-ary N-cubesAll-to-all personalized communication pattern(plete-exchange)is the most dense communication pattern among various communication patterns which arise in the implementation of various applications on distributed mem-ory machines.I along with Yu-chee Tseng,who was my colleague at Ohio State University,developed a direct(i.e. without message combining)complete-exchange protocol for wormhole routed multidimensional torus networks.Our algorithm used optimal number of contention-free communication phases[49,50].The algorithm used the property that a2D torus network can be viewed as a cross product graph of two rings.Wefirst developed an optimal complete exchange communication schedule for a ring and then extended it to a tours network by using a notion of cross product of communication ter in collaboration with Dhableshwar Panda(a faculty at Ohio State University),we developed indirect complete exchange algorithms for wormhole routed2D and3D networks[51,52].Besides communication protocols for torus networks,I have also done some work on barrier synchronization al-gorithms for k-ary n-cubes[21]and processor allocation for torus connected multiprocessor systems[22,23]. References[1]I.D.Aron and S.K.S.Gupta.A witness-aided routing protocol for mobile ad hoc networks with unidirectionallinks.In H.V.Leong,W.-C.Lee,B.Li,and L.Yin,editors,Proc.of First Int’l Conference on Mobile Data Access (Lecture Notes in Computer Science LNCS1748),Dec.1999.[2]I.D.Aron and S.K.S.Gupta.Analytical comparision of local and end-to-end error recovery in reactive rout-ing protocols for mobile ad hoc networks.In Proc.4th Int’l Workshop on Modeling Analysis and Simulation of Wireless and Mobile Systems(MSWiM’00),Aug.2000.[3]D.Barbara and T.Imielinski.Sleepers and Workaholics:Caching Strategies in Mobile Environments.Very LargeDatabases Journal,Dec.1995.[4]V.Bharghavan.Challenges and solutions to adaptive computing and seamless mobility over heterogeneous wire-less networks.International Journal on Wireless Personal Communications:Special Issue on Mobile Wireless Networking,Mar.1997.[5]C.C.Chiang and M.Gerla.Routing and multicast in multihop,mobile wireless networks.In Proceedings ofICUPC’97,Oct.1997.[6]D.L.Dai,S.K.S.Gupta,S.D.Kaushik,J.H.Lu,R.V.Singh,C.-H.Huang,P.Sadayappan,and R.W.John-son.EXTENT:A portable programming environment for designing and implementing high-performance block-recursive algorithms.In Supercomputing’94,pages49–58,1994.[7]S.K.S.Gupta,A.Bouabdallah,and P.K.Srimani.Self-stabilizing protocol for shortest-path tree for multicastrouting in mobile ad hoc networks.In Proc.EuroPar2000,Apr.2000.[8]S.K.S.Gupta,C.-H.Huang,P.Sadayappan,and R.W.Johnson.On the synthesis of parallel programs fromtensor product formulas for block recursive algorithms.In U.Banerjee,D.Gelernter,A.Nicolau,and D.Padua, editors,Conf.Rec.5th Int’l Workshop on Languages and Compilers for Parallel Computing,volume757of LNCS, chapter17,pages264–280.Springer Verlang,1993.[9]S.K.S.Gupta,C.-H.Huang,P.Sadayappan,and R.W.Johnson.Programming FFT in High Performance Fortran.In Proc.Int’l Conf.on Parallel and Distributed Systems,pages284–289,1993.[10]S.K.S.Gupta,C.-H.Huang,P.Sadayappan,and R.W.Johnson.A framework for generating distributed-memoryparallel programs for block recursive algorithms.J.Parallel and Distributed Computing,34(2):137–153,May 1996.[11]S.K.S.Gupta,C.-H.Huang,P.Sadayappan,and R.W.Johnson.A technique for overlapping computation andcommunication for block-recursive algorithms.Concurrency:Practice And Experience,10(2):73–90,Feb.1998.[12]S.K.S.Gupta,S.D.Kaushik,C.-H.Huang,J.R.Johnson,R.W.Johnson,and P.Sadayappan.A methodologyfor the generation of data distributions to optimize communication.In Fourth IEEE Symposium on Parallel and Distributed Processing,pages436–441,Dec.1992.[13]S.K.S.Gupta,S.D.Kaushik,C.-H.Huang,J.R.Johnson,R.W.Johnson,and P.Sadayappan.Towards automaticderivation of data distributions from tensor product formulas.In Proc.3rd Workshop on Compilers for Parallel Computers,pages372–392,Vienna,Austria,July1992.[14]S.K.S.Gupta,S.D.Kaushik,C.-H.Huang,J.R.Johnson,R.W.Johnson,and P.Sadayappan.A methodologyfor the generation of data distributions to optimize communication.ACM SIGPLAN Notices,Proc.of Workshop on Langauges,Compilers,and Run-time Environments for Distributed-Memory Multiprocessors,28(1):82–82, 1993.[15]S.K.S.Gupta,S.D.Kaushik,C.-H.Huang,and piling array expressions for efficient exe-cution on distributed-memory machines.J.Parallel and Distributed Computing,32(2):155–172,1996. [16]S.K.S.Gupta,S.D.Kaushik,S.Mufti,S.Sharma,C.-H.Huang,J.R.Johnson,R.W.Johnson,and P.Sadayappan.On the generation of efficient data communication for distributed-memory machines.In Proc.Int’l Computing Symposium,Taiwan,pages504–513,1992.Techinal Report OSU-CIS-RC-5/92-TR13,Dept.of Computer and Information Science,The Ohio State University,May1992.[17]S.K.S.Gupta,S.D.Kaushik,S.Mufti,S.Sharma,C.-H.Huang,and P.Sadayappan.On compiling array expres-sions for efficient execution on distributed-memory machines.In Proc.Int’l Conf.Parallel Processing,volume II, pages301–305,1993.[18]S.K.S.Gupta and S.Krishnamurthy.An interprocedural framework for determining efficient data redistributionsin distributed memory machines.In Proc.6th Symp.on the Frontiers of Massively Parallel Computation,pages 223–240,Annapolis,Maryland,1996.[19]S.K.S.Gupta and S.Krishnamurthy.An interprocedural framework for determining array data redistribution.J.Information Science and Engineering,Special Issue on Compiler Techniques for High-Performance Computing, 14(1):27–51,Mar.1998.。
Cisco工业以太网1000系列交换机数据表说明书
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Data SheetCisco Industrial Ethernet 1000 Series SwitchesProduct OverviewThe Cisco® Industrial Ethernet (IE) 1000 Series Switches are compact rugged switches aimed at operational technology (OT) users with limited IT network knowledge. The IE 1000 Series Switches provide an easy transformation from the legacy factory to digital solution. For machine builders and machine-to-machine (M2M) solutions, it is an attractive entry level product as a GUI-based, lightly-managed switch. The IE 1000 is a good fit for locations with harsh temperatures and small spaces and is Power over Ethernet (PoE) capable with zero IT management.The IE 1000 is ideal for industrial Ethernet applications where small and easy-to-be-managed hardened products are required, including factory automation, intelligent transportation systems, city-surveillance programs, building automations etc.The Cisco IE 1000 Series Switches complement the current industrial Ethernet portfolio of related Cisco industrial switches, such as the Cisco IE 2000, IE 3000, IE 4000 and IE 5000 Series managed Switches.The IE 1000 can be easily installed on your network. Through a user-friendly web device manager, the IE 1000 provides easy out-of-the-box configuration and simplified operational manageability to deliver advanced and secure multiservices over industrial networks.Features and BenefitsThe Cisco IE 1000 Series Switches are designed for low cost, low ports, and small sizes. They offer:●Scalability: Four models are available supporting 5, 6, 8 and 10 Ethernet ports, with Fast Ethernet (FE) andGigabit Ethernet (GE), copper and fiber uplinks options●Easy integration: Zero-touch IP discovery or Dynamic Host Configuration Protocol (DHCP)IP addressingand simple web GUI-based management●PnP (Plug and Play): Automates the process of provisioning the new devices in to the network by applyingconfigurations, installing required image without manual intervention.●Fast startup time: Starts 30 seconds from cold boot●Manageability: Web GUI interface, and diagnostics and analysis options through Simple NetworkManagement Protocol (SNMP) and syslog●Security: secure access; port-security; TACACS+ and RADIUS AAA Client: Security protocols to controlaccess into networks;●IEEE 802.1x security: Provides an authentication mechanism to devices wishing to attach to the network.Single host mode with MAC authentication bypass.●Minimize data load: VLAN aware, Internet Group Management Protocol (IGMP) and DHCP snooping tofilter unwanted data●Lightly-managed: Spanning-tree protocol (STP), Link Layer Discovery Protocol (LLDP), Cisco DiscoveryProtocol aware●Sticky-MAC: Enables the IE1K to retain MAC addresses it dynamically learns and avoid new devices toconnect on the port●BootP server with per-port support:When client sends a BootP request, the server responds with BootPresponse based on same DHCP pool configuration.●Gigabit uplink: Two fiber-optic SFP based uplink for up to 50 miles (80 kilometers) links●Industrial PoE: Up to eight PoE (IEEE 802.af) and PoE+ (802.3at) supported on selected models●Redundant voltage feeds, alarm relays support and DIN rail mount●Industrial environmental compliance and certifications: Ethernet/IP (CIP)Product Specifications●Maximum Forwarding Bandwidth 2.8Gbps●Maximum Switching Bandwidth 5.6GbpsDetailed Product InformationFigure 1 shows switch models, and Table 1 shows the Cisco IE 1000 Series Switches configuration information. Table 2 lists the SKUs for power supplies. Table 3 includes the 1000 product specifications. Table 4 lists software features. Table 5 includes compliance specifications. Table 6 outlines management and relevant industry standards.Figure 1. Cisco Industrial Ethernet 1000 Series SwitchesTable 1. Cisco IE 1000 Series Switches ConfigurationsTable 2. Power Supplies and Mounting Kit Available for Cisco IE 1000 Series Switches1 The entire power budget for the switch and PoE ports needs to stay within the power supply.2 The power supplies are not certified for smart grid and hazardous locations. These power supplies are IP20 rated.3 Power Supplies Datasheet Link: https:///c/en/us/products/collateral/switches/industrial-ethernet-switches/datasheet-c78-742180.htmlTable 3. Product SpecificationsTable 4. Cisco IE 1000 Software FeaturesTable 5. Compliance SpecificationsTable 6. Management and StandardsFigures 2 through 5 show the mechanical dimension details of the various IE 1000 models. Figure 2. IE1000-4T1T-LMFigure 3. IE1000-6T2T-LMFigure 4. IE1000-4P2S-LMFigure 5. IE1000-8P2S-LMWarranty InformationWarranty information for the Cisco IE 1000 Series Switches is available at https://www.cisco-/warrantyfinder.aspx.Cisco and Partner ServicesAt Cisco, we’re committed to minimizing our customers’ TCO, and we offer a wide range of services programs to accelerate customer success. Our innovative programs are delivered through a unique combination of people, processes, tools, and partners, resulting in high levels of customer satisfaction. Cisco Services helps you protect your network investment, optimize network operations, and prepare your network for new applications to extend network intelligence and the power of your business.Some of the key benefits our customers can receive from Cisco Services are:●Mitigating risks by enabling proactive or expedited problem resolution●Lowering TCO by taking advantage of Cisco expertise and knowledge●Minimizing network downtime●Supplementing your existing support staff so they can focus on additional productive activitiesFor more information about Cisco Services, visit Cisco Technical Support Services or Cisco Advanced Services athttps:///connectdots/serviceWarrantyFinderRequest?fl=sfCisco CapitalFlexible Payment Solutions to Help You Achieve Your ObjectivesCisco Capital makes it easier to get the right technology to achieve your objectives, enable business transformationand help you stay competitive. We can help you reduce the total cost of ownership, conserve capital, andaccelerate growth. In more than 100 countries, our flexible payment solutions can help you acquire hardware,software, services and complementary third-party equipment in easy, predictable payments. Learn more.For More InformationFor more information about the Cisco IE 1000 Series Switches, visit https:///go/ie1000 or contactyour local account representative.Printed in USA C78-737277-09 06/19。
宽带通信技术第七章网络拓扑发现
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网络拓扑发现的难点
发现网络拓扑是一项挑战性的工作,因为互联网是各种网络的 集合体,这些网络不但设备、软件差异很大,而且可能被不同 的组织所管理,他们的组织、运营、安全等措施互不相同。
网络规模越来越大,而且变化非常快(特别是无线网络),更 增加了拓扑发现的难度。
大多数网络管理工具都具有拓扑发现的功能
如HP Openview,IBM’s Tivoli等,它们大都依赖于简单网络管理 协议(SNMP)这一标准协议。而SNMP并不是一种通用的协议, 基于SNMP的拓扑发现受到权限的限制,没有权限便不能访问其支 持的MIBII信息,也便无法进行拓扑发现。
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NLANR(应用网络研究国家实验室)
9
拓扑发现的重要意义(续)
研究拓扑敏感算法
一些新的协议和算法可以在得到网络拓扑信息的基础上改善网络 性能。
确定镜像服务器的位置
根据拓扑信息合理配置镜像服务器的位置以最大可能减少时延, 解决瓶颈问题。
实行网络服务管理
例如:mail,ftp,web,snmp,dns。
10
拓扑发现的重要意义(续)
令a(b)为交换机a到节点b的转发端口。 相互连接的交换机网络中的两种情况
1. 各交换机属于同一子网 2. 各交换机属于不同子网(留给大家思考)
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基于完全表交换信息的拓扑发现-算法
1 发现节点:由ipAddrTable发现子网,由
ipRouteTable发现路由器,由ipForwarding及有无 Bridge MIB判断交换机。
National Laboratory for Applied Network Research
dsr 路由协议英文介绍
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dsr 路由协议英文介绍DSR (Dynamic Source Routing) is a routing protocol used in computer networks that enables nodes to dynamically determine the optimal path for data transmission. It is a proactive routing protocol, meaning that it maintains route information in advance rather than waiting for a request.DSR works by establishing a route discovery process. When a source node wants to send data to a destination node, it broadcasts a route request packet to all the nodes in the network. Each intermediate node that receives the request packet appends its own address to the packet and forwards it to its neighbors. The destination node, upon receiving the request packet, generates a route reply packet that contains the optimal path back to the source node.One notable feature of DSR is its support for source routing. In source routing, the source node determines the complete sequence of nodes through which the data packets will travel. This allows for more efficient routing, as nodes do not need to maintain routing tables or perform extensive route calculations.Another advantage of DSR is its ability to handle network topology changes effectively. If a node moves or fails, DSR can quickly adapt to the new conditions by dynamically discovering alternative routes.However, DSR has some limitations. It requires additional overhead due to the inclusion of the complete route in the packet header. This can increase the size of the packets and consumenetwork bandwidth. Additionally, DSR may not be suitable for large-scale networks with a high node density, as the overhead can become significant.In summary, DSR is a routing protocol that enables dynamic route determination by utilizing source routing. It offers efficiency and adaptability in small to medium-sized networks but may not be suitable for large-scale deployments.。
专业名词对照
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A:A Postal Class of Service 邮政类型服务Anycast 任播Administrative Records 管理记录Abandonment 放弃Aware 感知B:bundle 聚束bundle layer 聚束层bundle protocol agent 聚束协议代理,简称BPA Bundle payload聚束负载Bundle node聚束节点Bundle Fragmentation 聚束分片Bundle Deletion 聚束监测Bundle Status Reports, or BSRs 聚束状态报告C:challenged network 受限网络Class of Service 服务类别,简写COS Custody Transfer 监管传输Custody 监管custodian 监管者Custody Acceptance 监管接受Custody Release监管释放Convergence layer adapters (CLA)聚束层适配器Custody Signals监管信号Contact 连接,链接Core node 核心节点Convergence layer 汇聚层D:DARPA 美国国防部高级研究局data rate 数据率Direct Delivery 直接传输Delay Tolerant Networks 容滞网络,简写DTNDelivery递交Deletion, Discarding 监测删除Deployment area 部署区域Deposit 转储E:Exotic Media Networks 外来媒体网络Erasure-coding based routing 基于纠删码的路由Epidemic 蔓延路由Endpoint IDs终端IDExpiration满期Earliest Delivery 最早投递算法,简称EDEarliest Delivery with Local Queuing 考虑本地队列的最早投递算法,简称EDLQ Earliest Delivery with All Queuing 考虑所有队列的最早投递算法,简称EDAQ Earliest Delivery with Remote 考虑后续节点队列的最早投递算法,简称Queuing EDRQEarliest Delivery with Limited 考虑节点工作时间的最早投递算法,简称Working Time EDWTEarliest Delivery with Queuing 考虑后续节点队列和工作时间的最早投递and Time 算法,简称EDQTExternal trace 外部追踪Established route 既定路由F:Ferry node 摆渡节点Fragment 分片First Contact 最先连接算法,简称FCFIFO 先进先出Flooding 洪泛H:Human Networks 人群网络I:interplanetary networking 星际互联网,简写IPNIPNSIG IPN特别兴趣组K:Knowledge Oracle 先验知识库L:latency 延迟low-duty –cycle 低占空比Long queuing delay 长排队延迟Low Duty Cycle Operation 低占空比操作Link-State Protocol 链路状态协议Lifetime生命期Linear Programming 线性规划法,简称LPLink-by-link route 逐链路路由M:Military Ad-Hoc Networks 军事无线自组织网络Message 消息Multicast 组播Minimum Expected Delay 最小期望延迟算法,简称MEDMalicious node 恶意节点N:naming scheme 命名机制O:ONE 机会网络仿真软件(Opportunistic NetworkEnvironment simulator)P:persistent storage 持久存储Polling 轮询propagation delay 传播延迟Proactive 主动PROPHET 基于概率路由协议(Probabilistic RoutingProtocol using History of Encounters andTransitivity)Parting 分区Q:queuing time 排队时间;排队延迟R:Reactive 被动Registration注册Random-way point 随机路点Retrieve 检索S:Sensor and Sensor/Actuator Networks 传感器和传感器/执行器网络store-and-forward 存储-转发Self-Delimiting Numeric Values 自定义数值(SDNVs)Spray and wait 散发和等待Source Spray and wait 源端散发和等待Binary Spray and wait 二分法散发和等待T:Terrestrial Mobile Networks 陆地移动网络the Licklider Transmission Protocol 链路传输协议,简写LTPthe Bundle Protocol 聚束协议,简写BPTCP convergence layer TCP汇聚层,简称TCP CLA Transmission传递Timestamp时间戳transmission delay 传输延迟V:V ANET 车辆网络Village networks 乡村网络U:URL 统一资源定位符W:Working Day Movement WDM模型。