Closure to “Comparison of Interface Shear Strength of Soil Nails Measured by Both Direct Shear Box

Juniper EX系列交换机命令行配置手册目录第一章交换机基础知识 (7)1.1认识J UNIPER交换机 (7)1.2J UNOS操作系统基础 (10)1.2.1 交换机配置模式 (10)1.2.2 交换机配置结构 (11)1.2.3 TAB和空格键的使用 (16)1.2.4 用户模式和配置模式show的区别 (17)1.2.5 如何将配置转换成set命令 (20)1.2.6 commit和rollback (21)1.3EX交换机命令菜单结构 (23)第二章操作指导 (36)2.1通过CONSOLE线连接交换机 (36)2.2 SYSTEM系统参数配置 (37)2.2.1设置root密码 (38)2.2.2设置主机名 (38)2.2.3设置DNS服务器 (38)2.2.4设置日期时间 (38)2.2.5设置NTP服务器 (39)2.2.6开启远程Telnet登陆服务 (39)2.2.7开启远程Ftp服务 (40)2.2.8开启远程ssh登陆 (40)2.2.9开启远程http登陆服务 (40)2.2.10添加/删除用户 (41)2.2.10.1添加用户 (41)2.2.10.2修改用户类别 (41)2.2.10.3 修改用户密码 (42)2.2.11用户权限设置 (42)2.3VLAN配置 (44)2.3.1 VLAN配置步骤 (44)2.3.2 VLAN配置规范要求 (45)2.3.3 添加VLAN (45)2.3.4 修改端口VLAN (47)2.3.5 删除VLAN (48)2.3.6 配置VLAN网关IP (48)2.4T RUNK配置 (48)2.4.1 Trunk配置步骤 (49)2.4.2如何设置Trunk (49)2.4.3允许/禁止VLAN通过Trunk (49)2.5端口配置 (49)2.5.1端口配置规范要求 (49)2.5.2修改端口速率 (50)2.5.3修改端口工作模式 (50)2.5.4修改端口为L3模式 (50)2.5.5 修改端口为L2模式 (51)2.6生成树配置 (51)2.6.1 RSTP协议概览 (51)2.6.2 MSTP协议概览 (54)2.6.3 STP配置实例（生成树） (56)2.6.4 RSTP配置实例（快速生成树） (57)2.6.5 MSTP配置实例（多生成树协议） (63)2.7端口捆绑 (68)2.7.1 端口捆绑步骤 (68)2.8ECMP负载均衡配置 (70)2.9路由协议配置 (72)2.9.1 静态路由配置 (72)2.9.1.1添加静态路由 (72)2.9.1.2 删除静态路由 (72)2.9.1.3调整静态路由优先值 (72)2.9.1.4设置备份静态路由 (72)2.9.1.5指定静态路由下一跳端口 (73)2.9.2 OSPF配置 (73)2.9.2.1 OSPF配置步骤 (73)2.9.2.2 OSPF配置实例（单区域） (77)2.9.2.3 OSPF路由过滤 (80)2.10端口镜像 (81)2.10.1 端口镜像的概述 (81)2.10.2 端口镜像的目的 (82)2.10.3 端口镜像的功能 (82)2.10.4 端口镜像工作原理 (82)2.10.5 端口输入输出流量镜像 (84)2.10.6 带过滤条件的端口镜像 (85)2.11端口MAC地址限制 (87)2.12端口广播风暴控制 (87)2.13VRRP虚拟路由冗余协议 (88)2.13.1 VRRP概览 (88)2.13.2 VRRP工作原理 (89)2.13.3 如何配置VRRP (90)2.14BFD配置（双向转发检测） (94)2.14.1 BFD概览 (94)2.14.2 BFD介绍 (95)2.14.3 BFD的报文格式 (95)2.14.4检测模式 (97)2.14.5发送周期及检测时间 (98)2.14.6参数修改 (99)2.14.7会话建立 (99)2.14.8BFD的标准化 (102)2.14.9OSPF中配置BFD (103)2.14.10静态路由中配置BFD (103)2.15交换机F IREWALL限制功能 (104)2.15.1限制IP地址 (104)2.15.2限制MAC地址 (105)2.16V IRTUAL-C HASSIS设置 (105)2.16.1VC知识 (106)2.16.2如何建立VC组 (107)2.16.3如何扩充VC组交换机 (109)2.16.4如何利用uplink链路组成VC (110)2.16.5如何对VC组进行切换 (113)2.17SNMP配置 (113)2.17.1SNMP协议概览 (113)2.17.2SNMP基本简介 (113)2.17.3配置SNMP (114)2.18S YSLOG配置 (116)第三章交换机维护操作 (116)3.1交换机启动和关闭 (116)3.1.1 交换机重启 (116)3.1.2交换机关闭 (116)3.2配置备份和恢复 (117)3.2.1 交换机文件备份 (117)3.2.2配置文件的恢复 (119)3.3如何升级交换机OS (119)3.4如何恢复出厂设置 (120)3.5密码恢复 (120)3.6日常维护命令 (122)3.6.1查看序列号show chassis hardware (123)3.6.2查看硬件show chassis hardware (123)3.6.3查看软件版本show version (123)3.6.4查看CPU show chassis routing-engine (123)3.6.5ping命令 (123)3.6.6查看设备告警信息 show chassis alarms (123)3.6.7查看详细的硬件温度及状态信息 show chassis environment (123)3.6.8查看接口VRRP状态信息show vrrp (123)第一章交换机基础知识1.1 认识Juniper交换机产品型号端口数端口类型PoE端口数最大电源容量(包括 PoE)EX 3200-24T 2410/100/1000B-T8190 (320) W EX 3200-24P 2410/100/1000B-T24190 (600) W EX 3200-48T 4810/100/1000B-T8190 (320) W EX 3200-48P 4810/100/1000B-T48190 (930) W产品型号端口数端口类型PoE端口数最大电源容量(包括 PoE)EX 4200-24T 24 10/100/1000B-T 8 190 (320) W EX 4200-24P 24 10/100/1000B-T 24 190 (600) W EX 4200-24F 24 100B-FX/1000B-X N/A 190 (190) WEX 4200-48T 48 10/100/1000B-T 8190 (320) WEX 4200-48P 48 10/100/1000B-T 48 190 (930) WEX 3200-48T前面面板EX 3200-48T 后面面板USBGbE管理口Console可插拔uplink模块LCD电源模块风扇模块RPS 连接头至少8 PoE端口EX 4200-48T 前面面板EX 4200-48T Rear ViewVCP (Virtual Chassis Port) 0 and1USB GbE管理口Console可插拔uplink模块LCD冗余可热插拔电源模块可插拔风扇模块至少8 PoE端口1.2 Junos操作系统基础Juniper交换机支持两种配置方式：采用命令行的CLI(command-line interface)配置方式，以及采用web浏览器界面JWeb配置方式。

Configuring Module Pre-ProvisioningThis chapter describes how to configure pre-provisioning for offline interfaces or modules in the Cisco Nexus5000Series switch.This chapter includes the following sections:•Information About Module Pre-Provisioning,page1•Guidelines and Limitations,page2•Enabling Module Pre-Provisioning,page2•Removing Module Pre-Provisioning,page3•Verifying the Pre-Provisioned Configuration,page4•Configuration Examples for Pre-Provisioning,page5Information About Module Pre-ProvisioningThe pre-provisioning feature allows you to preconfigure interfaces before inserting or attaching a module toa Cisco Nexus5000Series switch.If a module goes offline,you can also use pre-provisioning to make changesto the interface configurations for the offline module.When a pre-provisioned module comes online,thepre-provisioning configurations are applied.If any configurations were not applied,a syslog is generated.The syslog lists the configurations that were not accepted.In some Virtual Port Channel(vPC)topologies,pre-provisioning is required for the configurationsynchronization feature.Pre-provisioning allows you to synchronize the configuration for an interface that isonline with one peer but offline with another peer.Supported HardwareThe pre-provisioning feature supports the following hardware:•N2K-C2148T Fabric Extender48x1G4x10G Module•N2K-C2232P Fabric Extender32x10G Module•N2K-C2248T Fabric Extender48x1G4x10G Module•N51-M16EP Cisco16x10-Gigabit Ethernet Expansion Module•N51-M8E8FP Cisco 8Port 1/2/4/8G FC and 8Port 10-Gigabit Ethernet Expansion Module •N5K-M1008Cisco 8Port Fiber Channel Expansion Module 8x SFP •N5K-M1060Cisco 6Port Fiber Channel Expansion Module 6x SFP •N5K-M1404Expansion Module 4x 10GBase-T LAN,4x Fiber Channel •N5K-M1600Cisco 6-port 10Gigabit Ethernet SFP Module 6x SFP Upgrades and DowngradesWhen upgrading from Cisco NX-OS Release 4.2(1)N2(1)and earlier releases to Cisco NX-OS Release 5.0(2)N1(1),there are no configuration implications.When upgrading from a release that supportspre-provisioning to another release that supports the feature including InService Software Upgrades (ISSU),pre-provisioned configurations are retained across the upgrade.When downgrading from an image that supports pre-provisioning to an image that does not support pre-provisioning,you are prompted to remove pre-provisioning configurations.Guidelines and LimitationsPre-provisioning has the following configuration guidelines and limitations:•When a module comes online,commands that are not applied are listed in the syslog.•If a slot is pre-provisioned for module A and if you insert module B into the slot,module B does not come online.•There is no MIB support for pre-provisioned interfaces.•Cisco DCNM is not supported.Enabling Module Pre-ProvisioningYou can enable pre-provisioning on a module that is offline.Enter the provision model model command in module pre-provisionmode.After enabling pre-provisioning,you can configure the interfaces as though they are online.NoteSUMMARY STEPS1.configuration terminal2.slot slot3.provision model model4.exit5.(Optional)copy running-config startup-configConfiguring Module Pre-ProvisioningGuidelines and LimitationsDETAILED STEPSPurposeCommand or ActionEnters global configuration mode.configuration terminalExample:switch#config t switch(config)#Step 1Selects the slot to pre-provision and enters slot configuration mode.slot slotExample:switch(config)#slot 101switch(config-slot)#Step 2Selects the module that you want to pre-provision.provision model modelExample:switch(config-slot)#provision model N2K-C2248T switch(config-slot)#Step 3Exits slot configuration mode.exitExample:switch(config-slot)#exit switch#Step 4(Optional)Copies the running configuration to the startup configuration.copy running-config startup-configExample:switch#copy running-config startup-configStep 5This example shows how to select slot 101and the N2K-C2232P module to pre-provision.switch#configure terminal switch(config)#slot 101switch(config-slot)#provision model N2K-C2232P switch(config-slot)#exitRemoving Module Pre-ProvisioningYou can remove a module that has been pre-provisioned.SUMMARY STEPS1.configuration terminal2.slot slot3.no provision model model4.exit5.(Optional)copy running-config startup-configConfiguring Module Pre-ProvisioningRemoving Module Pre-ProvisioningDETAILED STEPSPurposeCommand or ActionEnters global configuration mode.configuration terminalExample:switch#config t switch(config)#Step 1Selects the slot to pre-provision and enters slot configuration mode.slot slotExample:switch(config)#slot 101switch(config-slot)#Step 2Removes pre-provisioning from the module.no provision model modelExample:switch(config-slot)#no provision model N2K-C2248T switch(config-slot)#Step 3Exits slot configuration mode.exitExample:switch(config-slot)#exit switch#Step 4(Optional)Copies the running configuration to the startup configuration.copy running-config startup-configExample:switch#copy running-config startup-configStep 5This example shows how to remove a preprovisioned module from a chassis slot:switch(config)#slot 2switch(config-slot)#no provision model N5K-M1404switch(config-slot)#Verifying the Pre-Provisioned ConfigurationTo display the pre-provisioned configuration,perform one of the following tasks:PurposeCommand Displays provisioned modules.show provision Displays module information.show module Displays switch profile information.show switch-profile Displays the running configuration without the pre-provisioned interfaces or modules that are offline.show running-config exclude-provisionDisplays the pre-provisioned commands that were not applied to the configuration when the interface or module came online.show provision failed-configConfiguring Module Pre-ProvisioningVerifying the Pre-Provisioned ConfigurationPurposeCommand This command also displays a history of failed commands.Displays the commands that were not applied when the interface ormodule came online.show provision failed-config interface Displays the running configuration including the pre-provisioned configuration.show running-config Displays the startup configuration including the pre-provisioned configuration.show startup-configConfiguration Examples for Pre-ProvisioningThe following example shows how to enable pre-provisioning on slot 110on the Cisco Nexus 2232P Fabric Extender and how to pre-provision interface configuration commands on the Ethernet 110/1/1interface.switch#configure terminal switch(config)#slot 110switch(config-slot)#provision model N2K-C2232P switch(config-slot)#exitswitch#configure terminalEnter configuration commands,one per line.End with CNTL/Z.switch(config)#interface Ethernet110/1/1switch(config-if)#description module is preprovisionedswitch(config-if)#show running-config interface Ethernet110/1/1Time:Wed Aug 2521:29:442010version 5.0(2)N1(1)interface Ethernet110/1/1description module is preprovisionedThe following example shows the list of pre-provisioned commands that were not applied when the module came online.switch(config-if-range)#show provision failed-config 101The following config was not applied for slot 33================================================interface Ethernet101/1/1service-policy input test interface Ethernet101/1/2service-policy input test interface Ethernet101/1/3service-policy input testThis example shows how to remove all pre-provisioned modules from a slot:switch(config)#slot 2switch(config-slot)#no provision model switch(config-slot)#Configuring Module Pre-ProvisioningConfiguration Examples for Pre-ProvisioningConfiguring Module Pre-Provisioning Configuration Examples for Pre-Provisioning。

1. a device can be assigned an IP address 192.168.13.175,with the mask being 255.255.255.240True FalseFalse2.an ospf hello message carries a list of known neighborsTrue FalseTrue3.only router-LSAs and Network-LSAs are involved in intra-area route calculationsTrue FalseTrue4.only one BGP process can be configured on a routerTrue FalseTrue5.an ip-prefix-filter is used to filter ip prefixes and data packetsTrue FalseFalse6.RSTP has all functions that STP has and it is backward compatible with STP.True FalseTrue7.TO enable an eudemon in routing mode to work like a router,you need to assign ip addressesto interfaces and enable dynamic or static routing protocols on the eudemon.True FalseTrue8.The eudemon that is working in transparent mode detects processes data at layer 2.Itsinterfaces are not configured with ip addresses.True FalseTrue9.When an eudemon is working in composite mode,some of its interfaces are configured withip addresses (Layer 3 interfaces) and the other interfaces are not configured with ip addresses(Layer 2 interafces). To enable dual-system hot backup on an eudemon,you can configure the eudemon to work in composite mode.True FalseTrue10.Two Eudemons in dual-system hot backup can be working in active-active mode oractive-standby mode.True FalseTrue11.The eudemon supports load balancing between multiple uplinks.True FalseTrue12.Different virtual firewall instances on an Eudemon must be configured with the same securitypolicy.True FalseFalse13.The firewall can be working in routing mode, transparent mode,or composite mode. Thedefault mode is the composite mode.True FalseFalse14.Virtual firewalls on the Eudemon are not allowed to access each other by default unless asecurity policy is specified.True FalseTrue15.IP addresses added to the blacklist of the Eudemon cannot be deleted.True FalseFalse16.You cannot set an aging time for the blacklist of the Eudemon.True FalseFalse17.The Eudemon generates a blacklist upon detecting an attack.True FalseFalse18.The Eudemon can control traffic and connections based on IP addresses.True FalseTrue19.The firewall does not use security rules to filter packets exchanged between interfaces in thesame zone.True FalseTruework address translation (NAT) translates only IP address information.True FalseFalse21.IP unnumbered is to borrow an IP address from an interface.If an interface has multiple IPaddresses,all its IP addresses will be borrowed and the primary address will continue after these IP addresses are borrowed.True FalseFalse22.When two Eudemon are working in dual-system hot backup mode,their session tables arebacked up in real time.True FalseTrue23.After an interface on a firewall is added to a zone, the interface belongs to the zone.True FalseTrue24.Status detection is an advanced communication filtering mechanism.It checks the applicationlayer protocol and monitors the status of the connection-based application layer protocol.For all connections,the status information about each connection is maintained by ASPF and is used to dynamically determine whether to permit or deny data packets to firewalls.True FalseTrue25.The NAT multi-instance function on the Eudemon independently maintains a NAT table foreach instance to provide address translation services for instances.True FalseTrue26.The IPSec function on the Eudemon supports NAT traversal.True FalseTrue27.The NAT function enabled on the Eudemon does not greatly affect system performance.True FalseTrue28.The Eudemon does not support port mapping.True FalseFalse29.In a Land attack,the source address and destination address of an SYN packet are both the IPaddress of the attacked object or a loopback address.True FalseTrue30.The association between the IDS and firewall requires that the IDS be directly connected tothe firewall.True FalseFalse31.Security policies for the firewall are applied to interzones but not to interfaces.True FalseTrue32.The multi-channel protocol is used to establish at least two channels(sessions) forcommunications or services.True FalseTrue33.ICMP packets are sent in a smurf attack and UDP packets are sent in a Fraggle attack.True FalseTrun34.The urgent pointer in the flag field of an IPv4 packet header is generally used for 00B datatransmission.True FalseTrue35.A firewall filters packets exchanged between zones but does not filter packets exchangedbetween intefaces in the same zone.True FalseTrue36.Two Eudemon in dual-system hot backup mode can be working in active-active mode oractive-standby mode.True FalseTrue37.Two Eudemon in dual-system hot backup mode use Huawei Redundancy Protocol(HRP) toback up key information (such as configuration commands and session status) between the active and standby devices.True FalseTrue38.The Eudemon uses the blacklist technology to associate with an NIP IDS.True FalseTrue39.Qos provides services of different qualities to meet various applicationrequirements,including dedicated bandwidth, decreased packet loss ratio,short packet transmission delay, and decreased delay and jitter.True FalseTrue40.In traffic shaping,the packet whose transmission rate exceeds the rate limit will be discardedor re-markedTrue FalseFalse41.WFQ can effectively control the delay and jitter by means of configuring weights for differentservices.True FalseTrue42.Congestion occurs when a link or node is carrying so much data that its quality of servicedeteriorates.True FalseTrue43.Most fields in IP headers of packets in the same data flow are identical,You can compressthese fields to improve the link transmission.True FalseTrue44.The variation in packet delay is called jitter.True FalseTrue45.The end-to-end delay is the sum of transmission delays,processing delays,and queuing delaysalong the packet forwarding path.True FalseTrue46.The data transmission rate depends on the bandwidth.True FalseTrue47.Packet loss occurs only on the packet receiverTrue FalseFalse48.Based on specific rules,traffic classification identifies packets having the same characteristics,Traffic classification is the prerequisite and basis for differentiated services.True FalseTrue49.Congestion management provides means to manage and control traffic when trafficcongestion occurs.True FalseTrue50.The traditional packet loss policy uses the Tail-Drop method.True FalseTrue51.The IP packet has a special field to mark the Qos. For example,the last 6 bits in the Tos field ofan IPv4 packet mark the DSCP value.True FalseFalse52.In traffic shaping, the packet whose transmission rate exceeds the rate limit will be discardedor re-marked.True FalseFalse53.WFQ can effectively control the delay and jitter by means of configuring weights for differentservices.True FalseTrue54.Congestion occurs when a link or node is carrying so much data that its quality of servicedeteriorates.True FalseTrue55.Most fields in IP headers of packets in the same data flow are identical. You can compressthese fields to improve the link transmission efficiency.True FalseTrueplex traffic classification matches packets with rules and then takes actions to matchingpackets.True FalseTrue57.Traffic shaping usually buffers packets that need to be dropped by traffic policing by means ofbuffer and token bucket.True FalseTrue58.In traffic policing using two token buckets,tokens are put into the CBS bucket at thecommitted information rate(CIR),The peak burst size(PBS) bucket is filled in only after the CBS bucket is full.True FalseTrue59.The interface IP address and virtual IP address configured for VRRP must not be identical.True FalseFalse60.A VRRP virtual router can have one or more IP addresses.True FalseTrue61.The virtual router uses a virtual MAC address but not the actual MAC address of the interfaceto respond to an ARP request.True FalseTrue62.A VRRP backup group is able to track the status of an interface. If the interface configuredwith a VRRP backup group fails or any interface on the router fails,the VRRP backup group providesTrue FalseTrue63.By using VRRP, the backup router in a VRRP backup group immediately becomes the masterrouter after detecting a fault and instructs its attached hosts to perform a master/slave switchover accordingly. This ensures that services will recover within a short period of time.True FalseFalse64.The reliability of a product or a system is generally evaluated with the two indicators of Meantime to repair (MTTR) and mean time between failures(MTBF).True FalseTrue65.BFD detects the link status immediately after a BFD session is set up .if BFD parameters aremodified or deleted at one end of the BFD session,the other end will consider such a modification or deletion as a fault and services will be then affected, Therefore,exercise caution when modifying or deleting BFD parameters.True FalseFalse66.One CV packet per second is generated on the ingress LSR of the LSP and receivd by theegress LSR, this generation rate is low and allows no adjustment,hence,the CV packet is usually used for checking the availability of a common LSP.True FalseTrue67.BFD packets are classified into control packets and echo packets.True FalseTrue68.A BFD session is set up following the three-way handshake during which parameters for theBFD session are negotiated. After the BFD session is set up,modifying the detection time parameters does not take effect.True FalseFalse69.The NSF function takes effect only after the GR function is enabled on two directly connectedrouters that use static routes for communication between users in different network segments.True FalseFalse70.During the GR of dynamic routing protocols(such as OSPF and BGP)neighbor relationshipsremain unchanged.True FalseFalse71.BFD is a common fast detection technology,It implements the fast switchover function onlywhen collaborating with other fast switchoverTrue FalseTrue72.BFD (a fast detection technology) enabled on a device quickly identifies a fault and reportsthe fault to the appropriate protocol modele after detecting a master/slave switchover on the neighboring devic,this causes the protocol module to quit the GR. AS such,BFD and GR cannot be used together.True FalseFalse73.In OSPF,the process of calculating shortest path tree can be divided into two phases,calculatetransit node first,then calculate stub network.True FalseFalse74.In the process of calculating SPF tree,the cost from a node to root node equals to metriclisted in the Router LSA generated by the node.True FalseFalse75.BGP is an exterior gateway protocol,which runs among Ass,It focuses on routes control andselection of optimal routes rather than discovery and calculation of routes.True FalseTrue76.OSPF supports the combination of a group of network segments.Such a group is also calledan area.In other words,an area is a set of network segments.True FalseTrue77.The value of ospf dr-priority ranges from 0 to 255 and the default value is 64.True FalseFalse78.A broadcast and an NBMA network.each having two or more routers,must both have a DRand a BDR.True FalseFalse79.The vlink-peer command is used to specify a peer IP address for setting up a virtual link.True FalseFalse80.Different types of networks cannot establish an adjacency in the Full state.True FalseFalse81.Different network segments can be in the same OSPF area and the same network segmentcan be in different OSPF areas.True FalseFalse82.OSPF supports two authentication modes:area authentication and interfaceauthentication.The two authentication modes cannot be configured at the same time.True FalseFalse83.Each router running OSPF has a router ID,A router ID is a 32-bit integer and uniquelyidentifies a router,Hence,even of routers in different Ass,the router IDs must be different.True FalseFalse84.The most remarkable characteristic of OSPF is that OSPF supports the link-state algorithm.True FalseTrue85.OSPF directly runs over the IP protocol,Its IP protocol number is 89True FalseTrue86.If the Router Priority of a router is set to 0,this router cannot be elected as a DR or a BDR.True FalseTrue87.On a non-broadcast network,OSPF has two operating modes:NBMA and P2MPTrue FalseTrue88.By default,the cost of an OSPF interface is related to interface bandwidth.The algorithm forcalculating the cost is:True FalseTrue89.On a broadcast network or an NBMA network,not all neighbors need to set upadjacencies.Therefore,the concept about the adjacency is applicable to only the broadcast network or the NBMA network.True FalseFalse90.The NBMA mode requires all the routers in the network to be fully connected:otherwise,itdoes not function.True FalseFalse91.When two routers exchange LSDB information by exchanging DD packets,a master/slaverelationship is established between the two routers,The router with a larger router ID is the master.True FalseTrue92.If both the ospf cost and bandwidth-reference commands are configured on an interface.thevalue set in the ospf cost command is used as the cost of the interface.True FalseFalse93.The bandwidth-reference parameter is measured in Mbit/sTrue FalseTrue94.The asbr-summary command only contains the not-advertise parameter but not theadvertise parameter.True FalseTrue95.Each DD packet has a DD sequence number for packet acknowledgment.A DD sequencenumber is two-byte long.True FalseTrue96.On a broadcast network or an NBMA network,a router with a higher Router Priority is electedas a DR.True FalseFalse97.The LS Sequence Number field is used to detect expired and duplicate LSAs,This field is asigned 32-bit integer and therefore the minimum LS Sequence Number is 0x80000000True FalseFalse98.The LSAs with the same LS Sequence Number and LS age are the same LSA.True FalseFalse99.ABRs of a Stub area do not flood type-5 and type-4 LSAs to the stub area.Therefore,the stubarea does not have the external AS routing capability.ABRs of the stub area advertise a default route to the stub area to guide packet forwarding to the external of the AS.True FalseTrue100.The ABR in a Totally Stubby area will not advertise Type-3,Type-4,and Type-5 LSAs to the Totally Stubby area.Instead,the ABR will advertise a default route to the Totally Stubby area to guide forwarding of packets destined for other areas.True FalseTrue101.The ABR of an NSSA will not advertise Type-4 and Type-5 LSAs to an NSSA but can import external routes into the NSSA.True FalseTrue102.Different from a Stub area,an NSSA supports Type-5 LSAs.True FalseFalse103.ABRs advertise link status information about connected non-backbone areas to the backbone area.The backbone area then advertises the routing information about the backbone area cannot be advertised to non-backbone ares.True FalseFalse104.Type 2-external routes always take precedence over type 1-external routes True FalseFalse105.The import-route limit command is used to set the maximum number of external routers that can be imported into an OSPF process.True FalseTrue106.An Autonomous System (AS) is a set of routers under a single technical administration,using the same routing policy.True FalseTrue107.BGP peers are automatically discovered by exchanging multicast packets.True FalseFalse108.The router ID configured in the system view takes precedence over the router ID configured in the BGP view.True FalseFalse109.A failure in establishing a BGP peer relationship can be addressed by checking the TCP connectivity and BGP peer configurations.True FalseTrue110.In BGP,performing MD5 authentication between BGP peers can protect them from Dos attacks.True FalseTrue111.In the VRP,by default,the routes imported by BGP are not automatically summarized.True FalseTrue112.Based on BGP route selection rules,a local route that is automatically summarized takes precedence over a local route that is manually summarized.True FalseFalse113.Once a BGP connection is established,a BGP speaker advertises all the optimal routes in the BGP routing table to its BGP peer.True FalseTrue114.Whatever changes occur in the BGP routing table,a BGP speaker advertises all the optimal routes in the BGP routing table to its BGP peerTrue FalseFalse115.In the VRP,by default,a BGP router automatically retransmits an Update packet to its BGP peer after the outbound routing policy of the BGP peer changes.True FalseTrue116.IGP routes can be installed into the BGP routing table by running either the network or import-route command.True FalseTrue117.In the VRP,by default,a BGP router does not automatically send a Refresh to request its BGP peer to retransmit an Update packet after the inbound routing policy of the BGP peer changes.True FalseFalseing the peer connect-interface command to establish multiple peer relationships between two routers connected through multiple links is recommended.True FalseTrue119.Based on BGP route selection rules,the route with the lowest local-preference is preferred.True FalseFalse120.Based on BGP route selection rules,the route with the smallest MED value is preferred.True FalseTrue121.The origin attribute of the BGP route that is imported by using the network command is IGP True FalseTrue122.The BGP community attribute is a well-known mandatory attribute.True FalseFalse123.An ACL is used to match routing information or data packet addresses so as to filter out the unmatched routing information or data packets.True FalseTrue124.The system can perform ACL rule matching only based on the configuration order of rules.True FalseFalse125.Generally,the performance of an IP-prefix-filter is higher than that of an ACL.True FalseTrue126.An AS-path-filter is used to filter as-path attributes of BGP routes.The as-path attribute is actually a character string defined by using a regular expression.True FalseTrue127.Default routes between routers are a low-cost solution.this is because using default routes requires less system resources than maintaining a complete routing table.True FalseTrue128.An AS-path-filter uses the regular expression[0-9]+$ to indicate all as-path attributes.True FalseFalse129.Regular expressions can be used in both the community-filter and AS-path-filter to define the attribute mode used for route filteringTrue FalseTrue130.Route filtering can filter not only routing information but also link-status information.True FalseFalse131.For link-status routing protocols,filtering routes in the inbound direction actually cannot block the transmission of link-status information.the filtering effect is that routes cannot be injected into the local routing table but neighbors can still receive complete route status information and calculate complete routes.True FalseTrue132.All routing protocols can deliver default routes,supporting both forcible delivery and non-forcible delivery.True FalseFalse133.IF different routing protocols run on different networks and these networks need to share routing information,route importing can be usedTrue FalseTrue134.The route selection tool route-policy can filter and set BGP attributes based on pre-defined conditions.therefore,this tool is commonly used to define policies for BGP peers and often used in routeTrue FalseTrue135.When importing routes discovered by other routing protocols,a routing protocol may need to import only the routes that meet the conditions and set attributes of the imported routes to meet the requirement of the protocol,In such a case,a route-policy can be created.True FalseTrue136.Policy-based routing and routing policy affect the forwarding of data packets in different ways:A routing policy mainly controls packet forwarding,According to the routing policy,packets can be forwarded with no need to use a routing table:policy-based routing mainly controls the importing,advertising,and receiving of routing information so as to affect the forwarding of data packets.True FalseFalse137.The unicast and multicast technologies are both outstanding in solving the problem of one source and multiple destinations for efficient P2MP data transmission.True FalseFalse138.The IGMP protocol runs between a host and its directly connected multicast router.True FalseTrueyer 3 switch has layer 2 capability as well as layer 3 routing capabilityTrue FalseTrue140.STP distributes configuration message by sending BPDU packet to each other True FalseTrue141.A switching network has been enabled with STP protocol.To provide fast access speed to the file server for most of the users,the switch that is directly connected with file server is configured as the root bridgeTrue FalseTrue142.IF loop exists and STP is not enabled,the switch will not operate normally True FalseTrue143.RSTP adopts fast convergence mechanism,So,there is no forward delay interval in RSTP True FalseFalse144.Two switches are directly connected to each other and they are working in full duplex mode.By default,RSTP will consider the link between the switches as point-to-point linkTrue FalseTrue145.In RSTP network environment,a port can be set as edge port when it is directly connected with terminalTrue FalseTrue146.In a switching network that runs RSTP,the topology change notification message will not be sent when the switch detects that the Alternate port is faile.True FalseTrue147.VLANs isolate broadcast domains,eliminates broadcast storms,and enhances information securityTrue FalseTrue148.Before establishing a network,we must create VLANs,the users that do not need to communicate with each other should be added to the same VLAN for isolationTrue FalseFalse149.The port isolation function can isolate the ports on the same switchTrue FalseTrue150.When configuring VLAN mapping,you must set the priority of outer VLAN ID True FalseFalse151.On a switch running GVRP,each interface is considered as a participant.the participants can exchange informationTrue FalseTrue152.A switching network has been enabled with STP protocol,To provide fast access speed to the file server for most of the users,the switch that is directly connected with file server isconfigured as the root bridgeTrue FalseTrue153.When configuring VLAN mapping,you must set the priority of outer VLAN ID True FalseFalse154.QinQ provides a simplified layer 2 VPN tunnelTrue FalseTrue155.The STP protocol cannot prevent MAC address table flapping caused by loops on the layer 2 networkTrue FalseFalse156.According to the MSTP protocol,each MST instance calculates an independent spanning tree by using the RSTP algorithmTrue FalseTrue157.The traditional antivirus system prevents viruese on each node separately and may fail to prevent many security threatsTrue FalseTrue158.NAC is an end-to-end security solution.it protects network security from user terminals instead of network devicesTrue FalseTrue159.If 802.1x authentication is enabled on an interface,MAC address authentication (enabled by the mac-authen enable command) and direct authentication(enabled by the direct-authen enable command) cannot be enabled on the interfaceTrue FalseTrue160.The option field in DHCP messages uses the CLV modeTrue FalseTrue161.The option field in DHCP messages has a fixed length of four bytesTrue FalseFalse162.If only some devices on a network run MPLS (MPLS domain is encapsulated in the IP packet header),labels are generated only for direct routes of devices running bels are not generated for the routes originated from other devices running IP protocolsTrue FalseTrue163.The core of the MPLS technology is label switching.True FalseTrue164.In MPLS VPN configuration,you can choose from various types of routing protocols to configure between PEs and CEs.any type of routes can be imported to a VPN instance by using the import commandTrue FalseTrue165.VRF refers to VPN instance.It is an entity that a PE maintains for its directly connected site True FalseTrue166.On an MPLS VPN network,CEs and PEs can use the same routing protocol or different routing protocols to exchange routing information,the routing protocols are independent from one anotherTrue FalseTrue。

C H A P T E R54-1Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-0154Configuring Storm ControlThis chapter describes how to configure port-based traffic control on the Catalyst 4500 series switch.This chapter consists of these sections:•About Storm Control, page 54-1•Enabling Broadcast Storm Control, page 54-3•Enabling Multicast Storm Control, page 54-4•Disabling Broadcast Storm Control, page 54-5•Disabling Multicast Storm Control, page 54-5•Displaying Storm Control, page 54-6NoteFor complete syntax and usage information for the switch commands used in this chapter, first look at the Cisco Catalyst 4500 Series Switch Command Reference and related publications at this location:/en/US/products//hw/switches/ps4324/index.htmlIf the command is not found in the Catalyst 4500 Series Switch Command Reference, it will be found in the larger Cisco IOS library. Refer to the Cisco IOS Command Reference and related publications at this location:/en/US/products/ps6350/index.htmlAbout Storm ControlThis section contains the following subsections:•Hardware-Based Storm Control Implementation, page 54-2•Software-Based Storm Control Implementation, page 54-2Storm control prevents LAN interfaces from being disrupted by a broadcast storm. A broadcast storm occurs when broadcast packets flood the subnet, creating excessive traffic and degrading network performance. Errors in the protocol-stack implementation or in the network configuration can cause a broadcast storm.54-2Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-01Chapter 54 Configuring Storm ControlAbout Storm ControlSoftware Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-01Chapter 54 Configuring Storm ControlEnabling Broadcast Storm ControlEnabling Broadcast Storm ControlTo enable storm control, perform this task:The following example shows how to enable storm control on interface:Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# interface fa3/1Switch(config-if)# storm-control broadcast level 50Switch(config-if)# endSwitch# show storm-controlInterface Filter State Broadcast Multicast Level --------- ------------- --------- --------- -----Fi3/1 Forwarding Enabled Disabled 50.00% Switch# show int fa2/1 capabilities FastEthernet2/1Model: WS-X4148-RJ45V-RJ-45 Type: 10/100BaseTX Speed: 10,100,autoCommandPurposeStep 1Switch# configure terminalEnters global configuration mode.Step 2Switch(config)# interface interface-id Enters interface configuration mode and enter the port to configure.Step 3Switch(config-if)# storm-control broadcast level [high level ]Configures broadcast storm control.Specifies the upper threshold levels for broadcast traffic. The storm control action occurs when traffic utilization reaches this level.(Optional) Specifies the falling threshold level. The normaltransmission restarts (if the action is filtering) when traffic drops below this level for interfaces that support software-based suppression.NoteFor ports that perform hardware-based suppression, the lower threshold is ignored.NoteFor the Catalyst 4500-X Series Switch, on ports operating at 1Gigabit, thresholds less than 0.02% are not supported.Step 4Switch(config-if)# storm-control action {shutdown | trap }Specifies the action to be taken when a storm is detected.The default is to filter out the broadcast traffic and not to send out traps.The shutdown keyword sets the port to error-disable state during a storm. If the recover interval is not set, the port remains in shutdown state.Step 5Switch(config-if)# exit Returns to configuration mode.Step 6Switch(config)# endReturns to privileged EXEC mode.Step 7Switch# show storm-control [interface ] broadcastDisplays the number of packets suppressed.Step 8Switch# copy running-config startup-config(Optional) Saves your entries in the configuration file.Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-01Chapter 54 Configuring Storm ControlEnabling Multicast Storm ControlDuplex: half,full,auto Auto-MDIX: noTrunk encap. type: 802.1QTrunk mode: on,off,desirable,nonegotiate Channel: yesBroadcast suppression: percentage(0-100), hw Multicast suppression: percentage(0-100), hw Flowcontrol: rx-(none),tx-(none) VLAN Membership: static, dynamic Fast Start: yes CoS rewrite: yes ToS rewrite: yesInline power: yes (Cisco Voice Protocol) SPAN: source/destination UDLD: yes Link Debounce: no Link Debounce Time: no Port Security: yes Dot1x: yesMaximum MTU: 1552 bytes (Baby Giants) Multiple Media Types: no Diagnostic Monitoring: N/AEnabling Multicast Storm ControlCatalyst 4900M, Catalyst 4948E, Supervisor Engine 6-E, Supervisor Engine 6L-E, Supervisor Engine 7-E, and Supervisor Engine 7L-E support per-interface multicast suppression, which allows you to subject incoming multicast and broadcast traffic to interface-level suppression.NoteMulticast and broadcast suppression share a common threshold per interface. Multicast suppression takes effect only if broadcast suppression is enabled. Disabling broadcast suppression on an interface also disables multicast suppression.To enable multicast suppression, perform this task:The following example shows how to enable multicast suppression on ports that have broadcast suppression already enabled:Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# int fa3/1Switch(config-if)# storm-control broadcast include multicastCommandPurposeStep 1Switch# configure terminalEnters global configuration mode.Step 2Switch(config)# interface interface-id Enters interface configuration mode and enter the port to configure.Step 3Switch(config-if)# storm-control broadcast include multicast Enables multicast suppression.Step 4Switch(config-if)# exit Returns to configuration mode.Step 5Switch(config)# endReturns to privileged EXEC mode.Step 6Switch# show storm-controlVerifies the configuration.Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-01Chapter 54 Configuring Storm ControlDisabling Broadcast Storm ControlSwitch(config-if)# end Switch#Switch# show storm-controlInterface Filter State Broadcast Multicast Level --------- ------------- --------- --------- -----Fi3/1 Forwarding Enabled Enabled 50.00%Disabling Broadcast Storm ControlTo disable storm control, perform this task:The following example shows how to disable storm control on interface.Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# int fa3/1Switch(config-if)# no storm-control broadcast level Switch(config-if)# endSwitch# show storm-controlInterface Filter State Broadcast Multicast Level --------- ------------- --------- --------- -----Switch#Disabling Multicast Storm ControlTo disable multicast suppression, perform this task:CommandPurposeStep 1Switch# configure terminalEnters global configuration mode.Step 2Switch(config)# interface interface-id Enters interface configuration mode and enter the port to configure.Step 3Switch(config-if)# no storm-control broadcast levelDisables port storm control.Step 4Switch(config-if)# no storm-control action {shutdown | trap }Disables the specified storm control action and returns to default filter action.Step 5Switch(config-if)# exit Returns to configuration mode.Step 6Switch(config)# endReturns to privileged EXEC mode.Step 7Switch# show storm-control broadcast Verifies your entries.Step 8Switch# copy running-config startup-config(Optional) Saves your entries in the configuration file.CommandPurposeStep 1Switch# configure terminalEnters global configuration mode.Step 2Switch(config)# [no ] storm-control broadcast include multicastEnables and disables multicast suppression.Step 3Switch(config-if)# no storm-control broadcast levelDisables port storm control (broadcast and multicast).Chapter54 Configuring Storm Control Displaying Storm ControlCommand PurposeStep4Switch(config-if)# end Returns to configuration mode.Step5Switch(config)# end Returns to privileged EXEC mode.Displaying Storm ControlNote Use the show interface capabilities command to determine the mode in which storm control is supported on an interface.The following example shows an interface that supports broadcast suppression in software (sw):Switch# show int fa2/1 capabilitiesFastEthernet2/1Model: WS-X4148-RJ45V-RJ-45Type: 10/100BaseTXSpeed: 10,100,autoDuplex: half,full,autoAuto-MDIX: noTrunk encap. type: 802.1QTrunk mode: on,off,desirable,nonegotiateChannel: yesBroadcast suppression: percentage(0-100), hwMulticast suppression: percentage(0-100), hwFlowcontrol: rx-(none),tx-(none)VLAN Membership: static, dynamicFast Start: yesCoS rewrite: yesToS rewrite: yesInline power: yes (Cisco Voice Protocol)SPAN: source/destinationUDLD: yesLink Debounce: noLink Debounce Time: noPort Security: yesDot1x: yesMaximum MTU: 1552 bytes (Baby Giants)Multiple Media Types: noDiagnostic Monitoring: N/ANote Use the show interfaces counters storm-control command to display a count of discarded packets.Switch# show interfaces counters storm-controlPort Broadcast Multicast Level TotalSuppressedPacketsFa2/1 Enabled Disabled 10.00% 46516510Gi3/1 Enabled Enabled 50.00% 0Switch# show storm-controlInterface Filter State Broadcast Multicast Level--------- ------------- --------- --------- -----Fa2/1 Blocking Enabled Disabled 10.00%Gi3/1 Link Down Enabled Enabled 50.00%Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SGOL-25340-01。

一、为什么需要关闭和重新开启路由器或交换机某一接口在网络管理和维护过程中，有时需要关闭和重新开启路由器或交换机某一接口。

这可能是因为接口出现故障，需要重新初始化，或者需要进行某些配置调整，需要临时关闭接口。

无论是哪种情况，正确的操作命令对于网络的正常运行和维护非常重要。

二、路由器某一接口关闭并重新开启的命令1. 进入路由器的接口配置模式2. 找到需要关闭的接口3. 输入关闭接口的命令4. 输入重新启用接口的命令5. 退出接口配置模式具体的操作步骤如下：1. 进入路由器的接口配置模式在路由器的全局配置模式下，输入命令“interface 接口类型接口编号”进入接口配置模式。

如果需要关闭和重新启用以太网0/0接口，就输入命令“interface Ethernet0/0”。

2. 找到需要关闭的接口在接口配置模式下，找到需要关闭的接口。

可以通过命令“show interface”查看当前各个接口的状态，确认需要关闭和重新启用的接口编号。

3. 输入关闭接口的命令输入命令“shutdown”关闭接口，确保在关闭接口之前已经确认其不会影响整个网络的正常运行。

关闭接口后，可以通过命令“show interface”再次确认接口的状态。

4. 输入重新启用接口的命令输入命令“no shutdown”重新启用接口，确保在重新启用接口之前已经确认故障已经得到解决或者配置已经调整合适。

重新启用接口后，可以通过命令“show interface”再次确认接口的状态。

5. 退出接口配置模式输入命令“exit”退出接口配置模式，回到路由器的全局配置模式或者用户 EXEC 模式。

三、交换机某一接口关闭并重新开启的命令与关闭和重新启用路由器接口类似，关闭和重新启用交换机某一接口也有相应的命令操作步骤。

1. 进入交换机的接口配置模式2. 找到需要关闭的接口3. 输入关闭接口的命令4. 输入重新启用接口的命令5. 退出接口配置模式具体的操作步骤如下：1. 进入交换机的接口配置模式在交换机的全局配置模式下，输入命令“interface 接口类型接口编号”进入接口配置模式。

VDX 674 0 T-1G Sw it ch
The VDX 674 0 T-1G ( Fig ure 3) offers 4 8 10 0 0 BA SE-T p ort s and t w o 4 0 Gb E QSFP+ p ort s. Each 4 0 Gb E p ort can b e b roken out int o four ind ep end ent 10 Gb E SFP+ p ort s, p rovid ing an ad d it ional eig ht 10 Gb E SFP+ p ort s for up link. A ll 4 8 10 0 0 BA SE-T p ort s can b e up g rad ed t o 4 8 10 GBA SE-T p ort s via t he Cap acit y on Dem and (CoD) soft w are license. Tw o 4 0 Gb E p ort s are enab led as p art of t he b ase license. The ad d it ional t w o 4 0 Gb E p ort s can b e up g rad ed via t he Port s on Dem and ( PoD) soft w are license.
- Meet s t od ay?s ap p licat ion d em and s w it h high perform ance and low latency
- Delivers line-rate t hroughput for all p ort s and p acket sizes
Dat a Sheet

passive-interface / silent-interface
环境：Cisco router
passive interface
1）RIP和IGRP不用和邻接路由器建立邻接关系，当配置了'passive interface'后，该路由器仅从相应的接口收听相应的路由协议包，而不发送路由协议包。
2）passive interface'对OSPF，EIGRP则意义不大，因为这两种路由协议都要建立邻接关系。路由包不容许发送，邻接关系就建立不起来。因此在OSPF，EIGRP中，这条命令很少用到。
环境：Huawei router
silent-interface
1） 如果希望在某路由器上发布某直连路由，可以用import direct引入直连路由。但由于这样生成的是External LSA，会通告到整个自治域（stub区域除外），影响的范围较大。如果希望限制直连路由通告的范围，可以通过network命令在该接口上使能 OSPF，然后用silent-interface可以避免在该接口上发hello报文建立邻居。这样该直连路由就会以区域在网络的接入层，一般设备的级别较低，部署OSPF对设备的压力较大，而且，对于单链路上行的网络拓扑来说，配置静态路由也同样可以很好解决互通性问题。我们需要解决的问题是，如何将这些通过静态或者直联方式（运行OSPF的路由器的下行接口作为终端的网关）接入的业务网段引入到OSPF协议中，使整个网络的互通性得到保证。
2）此命令可以理解为不建立邻居，也有一定的安全作用．一般建议在与客户ＰＣ相连的网段启用该命令，防止恶意的建立邻居关系引起路由错乱。
// 一般情况下，OSPF process 下要把loopback 地址 silent-interface 掉；

Swift中的Closures（闭包）详解Swift 中的Closures(闭包)详解在Swift没有发布之前，所有⼈使⽤OC语⾔编写Cocoa上的程序，⽽其中经常被⼈们讨论的其中之⼀ -- Block ⼀直备受⼤家的喜爱。

在Swift 中，同样有这样的⼀个⾓⾊，⽤于当开发者需要异步执⾏的之后使⽤的⼀种语法 - Closure。

中⽂翻译为闭包。

闭包出了可以进⾏异步执⾏之外，它的完整使⽤还依赖闭包本⾝的变量、常量的捕获。

闭包捕获并存储对它们定义的上下⽂中的任何常量和变量的引⽤，这也就意味着，你可以在任何时候异步执⾏闭包的时候获取之前的所有的环境变量。

⽽实际上，闭包类似于Swift 中的匿名函数，在上⼀篇⽂章中，介绍了⾼阶函数和嵌套函数，它们和闭包有者不可分割的⼀些联系。

⽐如，最简单的闭包起始就是⼀个⾼阶函数，只是在闭包做为参数变量的时候，闭包是匿名、书写时实现。

当对于⼀般的⾼阶函数，闭包更轻量级。

本⽂介绍⼏种闭包的形式，以及⼀些闭包的特性。

⼀、闭包的基本形式这是⼀个最基本的闭包的形式：{ (parameters) -> return type instatements}闭包中，包含三要素：参数，返回类型，闭包体。

其中参数和返回类型可以忽略，但是⼀个闭包体必需存在，实际上就算在闭包体⾥⾯，什么都不写，闭包体本⾝还是以不执⾏任何代码的形式存在。

reversedNames = names.sorted(by: { (s1: String, s2: String) -> Bool inreturn s1 > s2})这是⼀个⾼阶函数，同时，也是⼀个闭包的基本使⽤。

包含了参数及类型，返回值类型，闭包体。

我们可以简写闭包的形式，采⽤内联的⽅式书写：reversedNames = names.sorted(by: { (s1: String, s2: String) -> Bool in return s1 > s2 } )在闭包中，因为包含了上下⽂的变量和常量的引⽤，并做了类型推断，所以，实际上，对于闭包的参数来说，类型是固定的,当然返回的类型也是固定的，swift允许开发者书写时省略。

EDS-P510A Series8+2G-port Gigabit PoE+managed Ethernet switches with8IEEE802.3af/at PoE+portsFeatures and Benefits•8built-in PoE+ports compliant with IEEE802.3af/at•Up to36W output per PoE+port•3kV LAN surge protection for extreme outdoor environments•PoE diagnostics for powered-device mode analysis•2Gigabit combo ports for high-bandwidth and long-distance communication •Operates with240watts full PoE+loading at-40to75°C•Supports MXstudio for easy,visualized industrial network management•V-ON™ensures millisecond-level multicast data and video network recoveryCertificationsIntroductionMoxa’s EDS-P510A Series has810/100BaseT(X),802.3af(PoE),and802.3at(PoE+)-compliant Ethernet ports,and2combo Gigabit Ethernet ports. The EDS-P510A-8PoE Ethernet switches provide up to30watts of power per PoE+port in standard mode and allow high-power output of up to36 watts for industrial heavy-duty PoE devices,such as weather-proof IP surveillance cameras with wipers/heaters,high-performance wireless access points,and IP phones.The EDS-P510A Ethernet Series is highly versatile,and the SFP fiber ports can transmit data up to120km from the device to the control center with high EMI immunity.The Ethernet switches support a variety of management functions,as well as STP/RSTP,Turbo Ring,Turbo Chain,PoE power management,PoE device auto-checking,PoE power scheduling,PoE diagnostic,IGMP,VLAN,QoS,RMON,bandwidth management,and port mirroring.The EDS-P510A Series is designed with3kV surge protection for harsh outdoor applications to increase the reliability of PoE systems.Additional Features and Benefits•Supports different PoE output settings(High-power36W,Forceand Legacy modes)to maximize powered device compatibility•Supports Smart PoE functions(PoE diagnosis,PD failure check,PoE scheduling,PoE Event Warning)to enhance PoE operationalefficiency•Command line interface(CLI)for quickly configuring majormanaged functions•DHCP Option82for IP address assignment with different policies•Supports EtherNet/IP and Modbus TCP protocols for devicemanagement and monitoring•Turbo Ring and Turbo Chain(recovery time<20ms@250switches),1RSTP/STP,and MSTP for network redundancy•Compatible with PROFINET protocol for transparent datatransmission•IGMP snooping and GMRP for filtering multicast traffic•Port-based VLAN,IEEE802.1Q VLAN,and GVRP to ease networkplanning•QoS(IEEE802.1p/1Q and TOS/DiffServ)to increase determinism•Port Trunking for optimum bandwidth utilization•TACACS+,IEEE802.1X,SNMPv3,HTTPS,and SSH to enhancenetwork security•Lock port function for blocking unauthorized access based on MACaddress•SNMPv1/v2c/v3for different levels of network management•RMON for proactive and efficient network monitoring•Bandwidth management to prevent unpredictable network status•Port mirroring for online debugging•Automatic warning by exception through email and relay output1.Gigabit Ethernet recovery time<50msSpecifications Ethernet InterfaceCombo Ports(10/100/1000BaseT(X)or100/ 1000BaseSFP+)2Full/Half duplex modeAuto MDI/MDI-X connection Auto negotiation speedPoE Ports(10/100BaseT(X),RJ45connector)8Full/Half duplex modeAuto MDI/MDI-X connectionAuto negotiation speedStandards IEEE802.1D-2004for Spanning Tree ProtocolIEEE802.1p for Class of ServiceIEEE802.1Q for VLAN TaggingIEEE802.1s for Multiple Spanning Tree ProtocolIEEE802.1w for Rapid Spanning Tree ProtocolIEEE802.1X for authenticationIEEE802.3for10BaseTIEEE802.3ab for1000BaseT(X)IEEE802.3ad for Port Trunk with LACPIEEE802.3af/at for PoE/PoE+outputIEEE802.3u for100BaseT(X)and100BaseFXIEEE802.3x for flow controlIEEE802.3z for1000BaseSX/LX/LHX/ZXEthernet Software FeaturesFilter GMRP,GVRP,IGMP v1/v2,Port-based VLANIndustrial Protocols EtherNet/IP,Modbus TCPManagement Back Pressure Flow Control,BOOTP,DDM,DHCP Option66/67/82,DHCP Server/Client,Fiber check,Flow control,IPv4/IPv6,LLDP,Port Mirror,RARP,RMON,SMTP,SNMP Inform,SNMPv1/v2c/v3,Syslog,Telnet,TFTPMIB Bridge MIB,Ethernet-like MIB,MIB-II,P-BRIDGE MIB,Q-BRIDGE MIB,RMON MIBGroups1,2,3,9,RSTP MIBRedundancy Protocols LACP,Link Aggregation,MSTP,RSTP,STP,Turbo Chain,Turbo Ring v1/v2 Security HTTPS/SSL,Port Lock,RADIUS,TACACS+,SSHTime Management NTP Server/Client,SNTPSwitch PropertiesIGMP Groups1024MAC Table Size8KMax.No.of VLANs64Packet Buffer Size1MbitsPriority Queues4VLAN ID Range VID1to4094Serial InterfaceConsole Port RS-232(TxD,RxD,GND),10-pin RJ45(19200,n,8,1)DIP Switch ConfigurationEthernet Interface Turbo Ring,Master,Coupler,ReserveInput/Output InterfaceAlarm Contact Channels1,Relay output with current carrying capacity of0.5A@48VDC Digital Input Channels1Digital Inputs Max.input current:8mA+13to+30V for state1-30to+3V for state0Power ParametersInput Voltage48VDC,Redundant dual inputsOperating Voltage44to57VDCInput Current 5.36A@48VDCPower Consumption(Max.)Max.17.28W full loading without PDs’consumptionPower Budget Max.240W for total PD consumptionMax.36W for each PoE portConnection2removable2-contact terminal block(s)Overload Current Protection SupportedReverse Polarity Protection SupportedPhysical CharacteristicsHousing MetalIP Rating IP30Dimensions79.2x135x105mm(3.12x5.31x4.13in)Weight1030g(2.28lb)Installation DIN-rail mounting,Wall mounting(with optional kit) Environmental LimitsOperating Temperature EDS-P510A-8PoE-2GTXSFP:-10to60°C(14to140°F)EDS-P510A-8PoE-2GTXSFP-T:-40to75°C(-40to167°F) Storage Temperature(package included)-40to85°C(-40to185°F)Ambient Relative Humidity5to95%(non-condensing)Standards and CertificationsSafety UL508EMC EN55032/24EMI CISPR32,FCC Part15B Class AEMS IEC61000-4-2ESD:Contact:6kV;Air:8kVIEC61000-4-3RS:80MHz to1GHz:20V/mIEC61000-4-4EFT:Power:2kV;Signal:2kVIEC61000-4-5Surge:Power:2kV;Signal:2kVIEC61000-4-6CS:10VIEC61000-4-8PFMFHazardous Locations Class I Division2Railway EN50121-4Traffic Control NEMA TS2Freefall IEC60068-2-31Shock IEC60068-2-27Vibration IEC60068-2-6MTBFTime708,972hrsStandards Telcordia(Bellcore),GBWarrantyWarranty Period5yearsDetails See /warrantyPackage ContentsDevice1x EDS-P510A Series switchCable1x DB9female to RJ4510-pinInstallation Kit4x cap,plastic,for RJ45port2x cap,plastic,for SFP slotDocumentation1x quick installation guide1x product certificates of quality inspection,Simplified Chinese1x product notice,Simplified Chinese1x warranty cardNote SFP modules need to be purchased separately for use with this product. DimensionsOrdering InformationModel NameCombo Ports10/100/1000BaseT(X)or100/1000BaseSFP+PoE Ports10/100BaseT(X),RJ45ConnectorOperating Temp.EDS-P510A-8PoE-2GTXSFP28-10to60°C EDS-P510A-8PoE-2GTXSFP-T28-40to75°CAccessories(sold separately)SoftwareMXview Industrial network management software designed for converged automation networksStorage KitsABC-02-USB Configuration backup and restoration tool,firmware upgrade,and log file storage tool for managedEthernet switches and routers,0to60°C operating temperatureABC-02-USB-T Configuration backup and restoration tool,firmware upgrade,and log file storage tool for managedEthernet switches and routers,-40to75°C operating temperatureSFP ModulesSFP-1FELLC-T SFP module with1100Base single-mode with LC connector for80km transmission,-40to85°Coperating temperatureSFP-1FEMLC-T SFP module with1100Base multi-mode with LC connector for4km transmission,-40to85°Coperating temperatureSFP-1FESLC-T SFP module with1100Base single-mode with LC connector for40km transmission,-40to85°Coperating temperatureSFP-1G10ALC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for10km transmission;TX1310nm,RX1550nm,0to60°C operating temperatureSFP-1G10ALC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for10km transmission;TX1310nm,RX1550nm,-40to85°C operating temperatureSFP-1G10BLC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for10km transmission;TX1550nm,RX1310nm,0to60°C operating temperatureSFP-1G10BLC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for10km transmission;TX1550nm,RX1310nm,-40to85°C operating temperatureSFP-1G20ALC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for20km transmission;TX1310nm,RX1550nm,0to60°C operating temperatureSFP-1G20ALC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for20km transmission;TX1310nm,RX1550nm,-40to85°C operating temperatureSFP-1G20BLC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for20km transmission;TX1550nm,RX1310nm,0to60°C operating temperatureSFP-1G20BLC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for20km transmission;TX1550nm,RX1310nm,-40to85°C operating temperatureSFP-1G40ALC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for40km transmission;TX1310nm,RX1550nm,0to60°C operating temperatureSFP-1G40ALC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for40km transmission;TX1310nm,RX1550nm,-40to85°C operating temperatureSFP-1G40BLC WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for40km transmission;TX1550nm,RX1310nm,0to60°C operating temperatureSFP-1G40BLC-T WDM-type(BiDi)SFP module with11000BaseSFP port with LC connector for40km transmission;TX1550nm,RX1310nm,-40to85°C operating temperatureSFP-1GEZXLC SFP module with11000BaseEZX port with LC connector for110km transmission,0to60°C operatingtemperatureSFP-1GEZXLC-120SFP module with11000BaseEZX port with LC connector for120km transmission,0to60°C operatingtemperatureSFP-1GLHLC SFP module with11000BaseLH port with LC connector for30km transmission,0to60°C operatingtemperatureSFP-1GLHLC-T SFP module with11000BaseLH port with LC connector for30km transmission,-40to85°C operatingtemperatureSFP-1GLHXLC SFP module with11000BaseLHX port with LC connector for40km transmission,0to60°C operatingtemperatureSFP-1GLHXLC-T SFP module with11000BaseLHX port with LC connector for40km transmission,-40to85°Coperating temperatureSFP-1GLSXLC SFP module with11000BaseLSX port with LC connector for500m transmission,0to60°C operatingtemperatureSFP-1GLSXLC-T SFP module with11000BaseLSX port with LC connector for500m transmission,-40to85°Coperating temperatureSFP-1GLXLC SFP module with11000BaseLX port with LC connector for10km transmission,0to60°C operatingtemperatureSFP-1GLXLC-T SFP module with11000BaseLX port with LC connector for10km transmission,-40to85°C operatingtemperatureSFP-1GSXLC SFP module with11000BaseSX port with LC connector for300/550m transmission,0to60°Coperating temperatureSFP-1GSXLC-T SFP module with11000BaseSX port with LC connector for300/550m transmission,-40to85°Coperating temperatureSFP-1GZXLC SFP module with11000BaseZX port with LC connector for80km transmission,0to60°C operatingtemperatureSFP-1GZXLC-T SFP module with11000BaseZX port with LC connector for80km transmission,-40to85°C operatingtemperaturePower SuppliesDR-120-48120W/2.5A DIN-rail48VDC power supply with universal88to132VAC or176to264VAC input byswitch,or248to370VDC input,-10to60°C operating temperatureDR-75-4875W/1.6A DIN-rail48VDC power supply with universal85to264VAC or120to370VDC input,-10to60°C operating temperatureDRP-240-48DIN-rail48VDC power supply with240W/5A,85to264VAC,or120to370VDC input,-10to70°Coperating temperatureSDR-480P-48DIN-rail48VDC power supply with480W/10A,90to264VAC,or127to370VDC input,(current sharingup to3840W),-25to70°C operating temperatureWall-Mounting KitsWK-46-01Wall-mounting kit,2plates,8screws,46x66.8x2mmRack-Mounting KitsRK-4U19-inch rack-mounting kit©Moxa Inc.All rights reserved.Updated Nov12,2018.This document and any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of Moxa Inc.Product specifications subject to change without notice.Visit our website for the most up-to-date product information.。

IP通信网络基础知识第一章，网际互连基础把一个大的网络划分为一些小的网络就称为网络分段，这些工作由路由器，交换机和网桥来按成。

引起LAN通信量出现足赛的可能原因如下:1．在一个广播域中有太多的主机2．广播风暴3．组播4．低的带宽路由器被用来连接各种网络，并将数据包从一个网络路由到另一个网络。

默认时，路由器用来分隔广播域，所谓广播域，是指王端上所有设备的集合，这些设备收听送往那个王端的所有广播。

尽管路由器用来分隔广播域，但重要的是要记住，路由器也用来分隔冲突域。

在网络中使用路由器有两个好处：1．默认时路由器不会转发广播。

2．路由器可以根据第三层（网络层）信息对网络进行过滤。

默认时，交换机分隔冲突域。

这是一个以太网术语，用来描述：某个特定设备在网段上发送一个数据包，迫使同一个网段上的其他设备都必须主要道这一点。

在同一时刻，如果两个不同的设备试图发送数据包，就会产生冲突域，此后，两个设备都必须重新发送数据包。

网际互连模型当网络刚开始出现时，典型情况下，只能在同一制造商的计算机产品之间进行通信。

在20世纪70年代后期，国际标准化组织创建了开放系统互联参考模型，也就是OSI七层模型。

OSI模型时为网络而构建的最基本的层次结构模型。

下面是分层的方法，以及怎样采用分层的方法来排除互联网络中的故障。

分层的方法参考模型时一种概念上的蓝图，描述了通信是怎样进行的。

他解决了实现有效通信所需要的所有过程，并将这些过程划分为逻辑上的组，称为层。

参考模型的优点OSI模型时层次化的，任何分层的模型都有同样的好处和优势。

采用OSI层次模型的优点如下，当然不仅仅是这些：1．通过网络组件的标准化，允许多个提供商进行开发。

2．允许各种类型网络硬件和软件相互通信。

3．防止对某一层所作的改动影响到其他的层，这样就有利于开发。

OSI参考模型OSI模型规范重要的功能之一，是帮助不能类型的主机实现相互之间的数据传输。

OSI模型有7个不同的层，分为两个组。

!
interface FastEthernet0/21
!
interface FastEthernet0/22
!
interface FastEthernet0/23
!
interface FastEthernet0/24
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
五、实际步骤
建立超级连接
建立CONSOLE连接
进入特权命令状态
进入全局状态模式
设置交换机的名字为SWITCH_2
进入接口设置状态，设置接口参数
（1）进入接口设置状态
（2）设置交换机的duplex方式
退出配置状态，在特权命令状态，验证端口工作状态
检查4台机的通信状态
设置switch2为端口VTP的server
Enter enable secret:
% No defaulting allowed
Enter enable secret:
% No defaulting allowed
Enter enable secret: switch>
The enable password is used when you do not specify an
Would you like to enable as a cluster command switch? [yes/no]: n
The following configuration command script was created:
hostname Switch
enable secret 5 $1$Aj2X$oQ4NIEhr7TX023s32vivd1

Chapter 4 The Network Layer 1．What is the name of a network-layer packet?（）A.messageB.segmentC.datagramD.frame2．What are the two most important network-layer functions in a datagram network? （）A.forwarding & routingB.forwarding & filteringC.routing & detectingD.routing & checking3．When a packet arrives at a router’s input link, the router must move the packet to the appropriate output link, this action is called ____? （）A.ForwardingB.routingC.cut throughD.filtering4．The network layer must determine the path taken by packets as they flow from a sender to a receiver. This action is called____? （）A.ForwardingB.routingC.cut throughD.examine5．A router forwards a packet by examining the value of a field in the arriving packet’s header, and then using this value to index into the router’s forwarding table, this value is? （）A.destination IP addressB.source IP addressC.destination MAC addressD.source MAC address6．IP belongs to ____ layer? （）A.transportworkC.data linkD.physical7．Which layer provides host-to-host services? （）A.transportworkC.data linkD.physical8．Which layer provides a connection service calledvirtual-circuit networks and a connectionless service called datagram networks? （）A.transportworkC.data linkD.physical9．IPV4 has a ___ bit address? （）A.48B.16C.32D.6410．MAC address is ____ bits? （）A.48B.16C.32D.6411．The Internet’s network layer has three major component s, the first component is the IP protocol, the second component is the routing protocol, the final component is____? （）A.forwardingB.address translationC.checkD.ICMP12．How many bits specify the IP protocol version in a datagram? （）A. 1 bitB. 2 bitsC. 4 bitsD.8 bits13．Most IPV4 datagram do not contain option field, how many bytes a header has in a typical IP datagram? （）A. 4 bytesB.8 bytesC.16 bytesD.20 bytes14．How many bits used in IP datagram express total length of the IP datagram? （）A. 4 bitsB.8 bitsC.16 bitsD.20 bits15．Data-grams are rarely larger than ____?（）A.1500 bytesB.65535 bytesC.500 bytesD.1024 bytes16．New version of IP----IPV6 does not allow fragment in ____?（）A.RouterB.HostC.Both of aboveD.None of above17．How does the TTL changed by one each time the datagram is processed by a router? （）A.decreaseB.increaseC.no changeD.always 018．Which layer protocol is indicated by the value of protocol field in IP datagram? （）A.applicationB.transportworkD.data link19．IP option is dropped in the ____ header. （）A.IPv6B.IPv4C.TCPD.UDP20．The data field in IP datagram can carry many types of data except ____. （）A.TCPB.UDPC.ICMPD.MAC21．ICMP is used for____?（）A.Reliable data transferB.Error reportingC.Flow controlD.Congestion control22．Suppose you receive an IP datagram from one link and check your forwarding table to determine the outgoing link, but this outgoing link has an MTU that is smaller than the length of IP datagram. Which technology will be used? （）A.resendB.discardC.fragmentD.none23．The designer of IPv4 decided to put the job of datagram reassembly in____.（）A.routerB.switchC.hubD.end system24．IP addressing assigns an address to 223.10.198.250/29, the network address for this network is____.（）A.223.10.198.248B.223.10.198.250C.223.10.198.0D.223.10.0.025．If all data-grams arriving at the router from WAN have the same destination IP address, then how does the router know the internal host to which it should forward a given datagram? The trick is to use ____ table at router, and include port numbers as well as IP address in the table entries. （）A.routingB.forwardingC.ARPD.NAT translation26．When running a Telnet, FTP, or HTTP session, you may haveencountered an error message such as “Destination network un-reachable”, This message had its origin in ____. （）A.IGMPB.EGPC.ICMPD.BGP27．The well-known ping program sends an (a) ____ type 8 code 0 message to the specified host. The destination hosts seeing the echo request, send back a type 0 code 0 ICMP echo reply. （）A.ICMPB.IGMPC.TCPD.UDP28．Tracer-out is implemented with ____ messages. （）A.IGMPB.TCPC.UDPD.ICMP29．The standard Tracer-out program actually sends sets of ____ packets with the same TTL. （）A.oneC.threeD.four30．IPv6 increases the size of the IP address from 32bit to ____ bit. （）A.64B.128C.256D.51231．How many bytes are there in header of IPv6? （）A.8B.20C.40D.3232．IPv6 does not allow for fragmentation and reassembly at inter-media ____. （）A.routersB.switchesC.end systemD.hubs33．From sender to receivers, all packets will take the same path, this is we use a ____ service. （）B.VCC.circuitD.Ethernet34．____ means moving packets from router’s input port to appropriate router output port? （）A.forwardingB.filteringC.routingD.switching35．____ means determining route taken by packets from source to destination? （）A.forwardingB.filteringC.routingD.switching36．A router works in ____ layer? （）workingB.Data linkC.ApplicationD.Physical37．A switch works in ____ layer? （）workingB.Data linkC.ApplicationD.Physical38．Networking layer provides services between two ____.（）A.HostsB.ProcessesC.ApplicationsD.Machines39．Link layer provides services between two ____. （）A.HostsB.ProcessesC.ApplicationsD.Machines40．The internet’s network layer provides a singleservice----that is ____.（）A.Reliable data transferB.Flow controlC.Congestion controlD.Best-effort-service41．Datagram network provides network-layer____.（）A.connectionless serviceB.connection serviceC.both of aboveD.neither of A and B42．VC network provides network-layer ____. （）A.connectionless serviceB.connection serviceC.both of aboveD.neither of A and B43．In VC network, each packet carries ____. （）A.VC identifierB.destination host addressC.IP addressD.Mac address44．A VC consists of three part, this three parts do not include____. （）A.Path from source to destinationB.VC numbers, one number for each link along pathC.Entries in forwarding tables in routers along pathD.Destination address45.In ____ networking, a series of packet may follow different paths and may arrive out of order? （）A.DatagramC.TCPD.None of above46．The internet is a (an) ____ network? （）A.DatagramB.VCC.Both of aboveD.None of above47．The four components of a router do not include____? （）A.Input and output portsB.Switch fabricC.Routing processorD.Switching processor48．There are three kinds of switch fabric for a router normally, those three switch fabric do not includes____?（）A.Switching via memoryB.Switching via a busC.Switching via an Interconnection-NetworkD.Packet switching49．Which of the following protocol is used for error reporting? （）A.ICMPC.IPD.UDP50．Which of the following is not a routing protocol? （）A.TCPB.RIPC.OSPFD.BGP51．IPV4 has a ___ bits address? （）A.32B.64C.16D.12852．IP address is identifier for ____. （）A.HostB.Router interfaceC.Both of aboveD.None of above53．“233.1.1.0/24”, where the /24 notation, sometimes known as a____. （）A.Subnet maskworking addressC.Host addressD.None of above54．Subnets with an 8-, ____-, and 24-bit subnet addresses were know as class A, B, and C networks respectively. （）A.9B.10C.12D.1655．IPV6 has a ___ bits address? （）A.32B.64C.16D.12856．____ means that IPv6 nodes also have a complete IPv4 implementation as well? （）A.Dual stackB.TunnelingC.Bridge connectionD.Forwarding57．____ means that IPv6 carried as payload in IPv4 data-gram among IPv4 routers? （）A.Dual stackB.TunnelingC.Bridge connectionD.Forwarding58．Typically a host is attached directly to one router, the ____ for the host. （）A.Default routerB.Source routerC.Destination routerD.Core router59．The default router of the source host is known as ____.（）A.Default routerB.Source routerC.Destination routerD.Core router60．The default router of the destination host is known as ____. （）A.Default routerB.Source routerC.Destination routerD.Core router61．A path between the source and destination that has beastcost is known as____. （）A.Least cost pathB.Shortest pathrgest cost pathD.None of above62．The path with the smallest number of links between the source and the destination is known as ____. （）A.Least cost pathB.Shortest pathrgest cost pathD.None of above63．Which of following about DV is not correct? （）A.IterativeB.SynchronousC.DistributedD.Self-terminating64．Which of the following is not intra-AS routing protocol? （）A.RIPB.OSPFC.IGRPD.BGP65．RIP is a kind of ____ algorithm. （）A.DVB.LSC.Both of aboveD.Neither of A and B66．OSPF is a kind of ____ algorithm. （）A.DVB.LSC.Both of aboveD.Neither of A and B67．The router in non-backbone areas and perform only intra-AS routing is known as ____. （）A.Internal routersB.Area border routersC.Backbone routersD.Boundary routers68．____“summarize” distances to nets in own area, advertise to other Area Border routers. （）A.Internal routersB.Area border routersC.Backbone routersD.Boundary routers69．____ runs OSPF routing limited to backbone. （）A.Internal routersB.Area border routersC.Backbone routersD.Boundary routers70．____ connect to other AS’s. （）A.Internal routersB.Area border routersC.Backbone routersD.Boundary routers71．Which of the following is an inter-autonomous system routing protocol? （）A.RIPB.OSPFC.IGRPD.BGP72．____means sending a packet to all other nodes in the network. （）A.BroadcastB.MulticastC.Any-castD.Uni-cast73．A ____ packet is delivered to only a subset of network nodes. （）A.BroadcastB.MulticastC.Any-castD.Uni-cast74．Means that the switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link. （）A.store-and-forward transmissionB.FDMC.End-to-end connectionD.TDM75．Datagram networks and virtual-circuit networks differ in ____.（）A.Datagram networks are circuit-switched networks, andvirtual-circuit networks are packet-switched networks.B.Datagram networks are packet-switched networks, andvirtual-circuit networks are circuit-switched networks.C.Datagram networks use destination addresses andvirtual-circuit networks use VC. Numbers to forward packets toward their destination.D.Datagram networks use VC. Numbers and virtual-circuitnetworks use destination addresses to forward packetstoward their destination.76．The Internet’s network layer is responsible for moving network-layer packets known as ____ from one host to another. （）A.frameB.datagramC.segmentD.message77．The protocols of various layers are called ____. （）A.the protocol stackB.TCP/IPC.ISPwork protocol78．The two important network-layer functions are ____. （）A.multiplexing and de-multiplexingB.routing and forwardingC.lookup and forwardingD.routing and IP addressing79．The virtual circuit includes three identifiable phases but ____. （）A.setupB.data transferC.forwarding VC numbersD.teardown80．There are some ways to accomplish the switching in the router, which one is not included? （）A.switching via memoryB.switching via a busC.switching via hubD.switching via an interconnection81．In the router, the packet queues can form at ____.（）A.institutional cacheB.switch fabricC.input portD.routing processor82．In IPV4 datagram header, which field is to ensure that datagram do not circulate forever in the network? （）A.type of serviceB.time-to-liveC.header checksumD.version83．Suppose one IP datagram of 5,000 bytes (20 bytes of IP header)and it must be forwarded to a link with an MTU of 1,500 bytes, the offset and flag of the second fragment in header are ____. （）A.185, 0B.185, 1C.370, 1D.370,084．Given the IP address 202.96.104.8/20, its subnet address is ____. （）A.202.96.104.0B.202.96.96.0C.202.96.104.255D.202.96.111.25585．If the subnet mask is 255.255.240.0, then how many bits indicate the host address? （）A.20B.24C.12D.1686．In the following four fields, which is in IPV6 header but not in IPV4? （）A.source addressB.destination addressC.versionD.flow label87．One host is attached directly to one router, the router is ____.（）A.NAT routerB.gateway routerC.first-hop routerD.interval router88．The Internet’s network layer includes the following components but ____.（）A.IP protocolB.the Internet Message Control ProtocolC.Routing ProtocolD.Channel Partitioning Protocol89．In the following protocols, which one is inter-AS routing protocol? （）A.RIPB.OSPFC.BGPD.ICMP90．In the following four descriptions about autonomous system,which one is not correct? （）A.An autonomous system is a collection of routers underthe same administrative and technical control.B.All routers in an autonomous system run the same routingprotocol.C.The routing algorithm running within an autonomoussystem is called an intra-AS routing protocol.D.The routers that connect AS-s to each other are calleddefault router.91．In the loop of the Dijkstra’s algorithm, for node x, add y to N’, and update the cost of y’s neighbor v, then D(v) is ____. （）A.c(x, v)B.min{D(v), D(x)+c(x, v)}C.min{D(v), D(y)+c(y, v)}D.c(y, v)92．Consider the data D is 01110010001, if use even parity checking approach, the parity bit is ( ), if use odd parity checking approach, the parity bit is ____. （）A.0, 0B.0, 1C.1, 0D.1, 193．The ability to determine the interfaces to which a frame should be directed, and then directing the frame to those interfaces is ____.（）A.filteringB.forwardingC.self-learningD.optimal routing94．Given that costs are assigned to various edge in the graph abstraction. In the following four descriptions, which one is not correct? （）A.The shortest path is the path with smallest number oflinks between the source and destination.B.The least cost path is not always the shortest path.C.If all edges have same cost, the least cost path mustbe the shortest path.D.If all edges have various costs, the least cost path mustnot be the shortest path.95．Given the IP address 202.96.104.8/20, its broadcast address is ____. （）A.202.96.104.0B.202.96.96.0C.202.96.104.255D.202.96.111.25596．If the subnet mask is 255.240.0.0, then how many bits indicate the host address? （）A.20B.12C.24D.1697．In IPV6 datagram header, the field Next-header is equivalent to the field ( ) in IPV4. （）A.upper-layer protocolB.time-to-liveC.header checksumD.version98．For one host, its source router is also called ____. （）A.NAT routerB.gateway routerC.first-hop routerD.interval router99．In the following four descriptions about link-state (LS) algorithm, which one is not correct? （）A.The LS algorithm must be aware of the cost of each linkin the network.B.The LS algorithm is a decentralized algorithmC.The LS algorithm computes the least cost path betweena source and destination using complete global knowledgeabout the networkD.The calculation of LS algorithm can be run at one siteor multiple sites100．In the initialization of the Dijkstra’s algorithm, for node x, if y is not a neighbor of x, then D(y) is ____. （）A.0B. 1C.∞D.c(x, y)101．In DV algorithm, when one node updates its distance vector, it must ____.（）A.send the updated routing table to its neighborsB.send the updated routing table to all the nodes in theASC.send the updated routing table at randomD.do nothing102．Now we had known IP address is 211.197.3.158/26, Pleasecompute :(1). Network address?(2). Broadcast address?(3). How many hosts are there in the network?(4). Fist host IP address?(5). Last host IP address? 103．For the given topology of the network, use Dijstra’s shortest path algorithm to compute the shortest path from A to all network nodes. Give a shortest path tree and node A’s routing table.104．The topology of a network shown as below. Using Link State routing algorithm to calculate the routing table in the node A. The vectors arrive to node C as bellow: B:( 4, 0, 8, 12, 6, 2 ); D:( 13, 10, 6, 0, 9, 10 ); E:( 7, 6, 3, 9, 0, 14 ). The delays measured from C to B, D, E are 4, 2, and 3separately. Update router C’s route table please.31。

接口封闭原则
接口封闭原则（Interface Segregation Principle，简称ISP）是面向对象设计原则之一，由罗伯特·C·马丁在他的《敏捷软件开发：原则、模式和实践》一书中提出。

接口封闭原则要求一个接口在设计时应该是稳定的，不应该频繁变更。

当需要添加新的功能时，应该创建新的接口而不是修改已有的接口。

这个原则的目的是避免已有的客户端代码受到接口的改变所导致的影响，从而提高系统的灵活性和可维护性。

通过将接口的职责进行划分，可以避免接口的膨胀，减少对接口的依赖，使得接口的修改对客户端代码的影响最小化。

接口封闭原则的主要思想是高内聚、低耦合。

高内聚意味着一个接口应该只有一个职责，不要承担过多的功能。

低耦合意味着接口之间应该尽量独立，不互相依赖。

总结起来，接口封闭原则就是要求我们将不同的功能分散到不同的接口中，避免一个接口承担过多的功能，从而提高系统的可维护性和灵活性。

Toward a Common Host Interface for Network ProcessorsAppearing in:Proceedings of the 2003IASTED International Conference on Communications,Internet,&Information Technology (CIIT),Scottsdale,Arizona,November,2003.Eric Hawkins Department of Computer Science California Polytechnic State University San Luis Obispo,CA 93407ehawkins@ Phillip L.NicoDepartment of Computer Science California Polytechnic State UniversitySan Luis Obispo,CA 93407pnico@Hugh SmithDepartment of Computer Science California Polytechnic State UniversitySan Luis Obispo,CA 93407husmith@AbstractSince their invention,network interfaces have generally been treated as special by operating systems because of their complexity and unique control requirements.In this paper we present a generic host interface through which an intelligent network interface or network processor can be managed as a simple networking device.To accomplish this,we push the complex network connection manage-ment and protocol processing code down onto the network interface.This new network processing platform is treated as a simple device by the host operating system.This model of host operating system interconnection provides for various network processor architectures to be handled identically using a well-defined kernel interface.Selection of the exact location for the kernel interface to the network processor was based on our goals to maximize the utility of the network processing platform,require no changes to existing network applications,and provide interoperability with existing network protocols (e.g.TCP,UDP).This pa-per documents the criteria and methodology used in devel-oping such a kernel interface and discusses our prototype implementation using Linux kernel modules and our own ASIC-based intelligent network interface card.Keywords:Information Systems and the Internet,Operat-ing Systems Support,intelligent NIC,network processors1IntroductionThe concept of offloading network processing from the host processor to a separate communication processor is not a new one.It has been discussed in the literature for some time,and several vendors have emerged to fill the newly created market niches for such devices.In order for such devices to be accepted into mainstream computing,however,a general interface is needed by which operating systems can offload network processing tasks to the co-Trapeze/Myrinet project[2]has shown impressive through-put across an intelligent network adapter,but it relies upon the Trapeze API to access the network adapter.Like-wise,the Nectar Communication Processor offloads pro-tocol processing as well as application specific tasks but does so through the use of the Nectarine programming in-terface which provides access to the Nectar message pass-ing facilities[1].Network processors based on the Intel I2O specifications which utilize a split-driver model to iso-late host functionality from network interface functionality are also bound to a custom API for the host-coprocessor interface[3].Since nearly all host-network processor inter-faces rely on custom APIs,the benefits of network proces-sors have not been realized on a broad scale.Incompatibil-ity with existing network software is a major impediment to the incorporation of these technologies.To address the issue of binary compatibility we have defined an interface to the network processor that works along with the socket programming interface.We have de-veloped a prototype system that uses a well-defined Linux kernel interface at the top of the protocol ing Linux kernel modules we have integrated support for the Cal Poly Intelligent Network Interface Card(CiNIC)[4] into the native Linux network protocol stack.Operations on CiNIC connections are dispatched through this interface in the host operating system to the CiNIC for protocol pro-cessing.Although the initial development has been done in Linux,the requirements and architecture of the interface can be applied to any operating system that supports the socket API.The rest of this paper is organized as follows:In Sec-tion2we discuss the requirements of the host-network pro-cessor interface.In Section3we describe the kernel level interface selection for our prototype implementation.In Section4we describe our implementation and prototype platform.In Section5we discuss directions for future work.In Section6we present conclusions from our work.2Interface RequirementsWe identified several requirements for the host-network processor interface.These requirements all stem from the primary requirement that our new OS interface be compat-ible with existing user-level interfaces so that existing pro-grams would not have to be altered.Use socket API:Since the majority of legacy network ap-plication code uses the socket API,the interface to the net-work processor must exist within the scope of socket calls. Figure1shows the traditional socket call interface.The socket API sits at the top of the network subsystem and provides user programs with an interface to the operating system’s network subsystem.The great majority of ex-isting network-based programs were written to the socket API,and so to ensure compatibility with existing programs the interface to the network processor must exist within the scope of the socket API.However,this requirement meansFigure1.Socket API and OS interface.that either the user-level socket library must be modified or support must be built into the OS.We chose the second ap-proach since OS modification is the best way to support the existing APIs and applications.Utilize native device management:The network proces-sor should be managed as a normal device by the host oper-ating system.Custom application-level code should not be required to manage the device.Rather,existing operating system support for synchronization and protection should be used.The justification for this requirement is that pro-duction operating systems use proved access management policies and procedures.With a well-designed interface to the network processor,these existing mechanisms can be utilized intact.Requiring network processors to be treated as special devices outside the scope of operating systems’existing device management facilities poses a potential se-curity and robustness risk.Look like a regular character device:To the host oper-ating system the network processor should appear to be a simple character device.The device should interact with the host operating system using a minimal number of oper-ations(open,read,write,close,etc.),and it should funda-mentally act like a simple device that raw data is written to and read from.This requirement is essential to preservingthe simplicity of the host-network processor interface.In implementation this requirement translates to locating the cleanest point at which to terminate host processing and in-voke the co-processor.Determination of the point at which this division should be made is driven by two considera-tions.First,the number of operations required for device support should be minimized in order to simplify the imple-mentation of the interface.Second,the data structures used by the operating system for network devices must be kept consistent on both the host and the co-processor with min-imum synchronization overhead.Many network related data structures are used at various points in the OS network-ing code and care must be taken to divide processing be-tween the host and co-processor such that minimal replica-tion of data is required.For example,the Linux kernel uses the socket data structure forfilesystem information such as the inode number while the sock data structure is used for socket-specific network connection information.It is nec-essary to have the sock available to the co-processor since it takes care of network processing.This requires the sock to either be replicated between the host and co-processor or available only to the co-processor.On the other hand, the socket is required by the host who takes care offilesys-tem management.However,due to interdependencies be-tween the data structures,separation of the two data struc-tures would require synchronization overhead,but replica-tion would require more.3The Socket Family InterfaceAs discussed in the previous section,the requirements for the host-network processor interface drove the design of the interface to be a kernel level modification.Several ex-isting interfaces within the Linux kernel appeared as poten-tial points to make the processing break between the host and co-processor.The host-network processor interface could be imple-mented by intercepting all socket system calls destined for network processor connections and redirecting these calls to the co-processor.The host OS’s system call table could be modified to redirect processing to functions capable of checking connections and dispatching calls appropriately. System call redirection minimizes the number of data struc-tures requiring synchronization between the host OS and network processing platform.Also,due to the high level at which the processing division is made,system call redirec-tion maximizes the amount of processing offloaded from the host to the co-processor.Unfortunately,the number of system calls and the requirement for catching all system calls makes this approach prohibitive in terms of imple-mentation and execution overhead.The mapping mech-anisms required to maintain network connections across multiple processes would also be complex and costly.Another possible OS interface is the Virtual Filesys-tem Switch(VFS).The VFS is a software layer within the kernel that handles system calls related to afilesystem.It provides a common interface to variousfilesystems through specification of the functions and data structures that must be implemented to support a particularfilesystem.The VFS seems like the natural spot to break host processing since it would allow network processor support to be im-plemented as a newfilesystem type.Operations destined for the co-processor would be redirected through the VFS interface and handled on the co-processor.However,the implementation of OS socket call handling makes the VFS an inappropriate point for interfacing to the co-processor. The primary reason for this is that not all socket process-ing proceeds through the VFS.The socketcall multiplexer is actually a parallel data path to the VFS through which network operations can alternately be invoked.For exam-ple,to receive data from a socket,an application can make a read call,which is handled by the VFS implementation of the read system call.Alternately,an application can make a recv call on a connected socket,which is handled by the socketcall multiplexer and does not interact directly with the VFS.The socket protocol family interface is a well-defined kernel interface just below the VFS layer.All socket pro-cessing converges from the VFS and socketcall multiplexer at the protocol family interface where it is dispatched to particular socket implementations.In the native network-ing code,this interface allows for the implementation of different socket types or protocol families.For example, with Internet domain sockets using the Internet Protocol (IP),this interface redirects socket processing to the set of data and operations defined for the Internet protocol family (PFCINIC,since our prototype implementation utilized the CiNIC as previously mentioned.Figure2shows the software architecture of the network processor interface us-ing the PFCINIC protocol family requires a minimal num-ber of functions to be implemented(17to be exact)due to the fact that the various possible data paths for socket op-erations converge at this point into the fundamental socket operations(e.g.create,release,connect,bind,sendmsg, recvmsg,etc).Another advantage of making the break in host pro-cessing at the protocol family interface is that it provides a low-level view of the socket based only on the kernel data structures.Integration of the socket into thefilesystem is handled by the kernel at a higher level,so all of thefilesys-tem maintenance operations such as allocating and main-tainingfile descriptors for sockets are automatically taken care of.This allows the network processor to function as a true networking device without the overhead offilesys-tem operations,which would be required if host processingNative Host Network Stack Network Processor StackFigure2.Protocol family interfacewas terminated at a higher level.The low-level view of the socket at the protocol family interface also limits the set of data structures affected by kernel operations on both the host and co-processor,providing for a clean separation of data between the host and co-processor with minimal syn-chronization requirements.Breaking the host network processing at the protocol family level allows multiple network protocols to be sup-ported by the co-processor.Protocol such as TCP/IP and UDP/IP are implemented at lower levels in the operating system,so processing destined for different types of sock-ets can proceed through the PFCINIC interface uses Linux loadable kernel modules, which are loaded prior to network processor usage much like a standard device driver.When host processing reaches the PFsocket_threads Figure4.Shared memory communication architecture.copies required for communication between the host and co-processor in our development platform.The current implementation requires data to be copied from the host to shared memory and from shared memory to the co-processor(and vice versa).Since data copy operations are a major bottleneck in network processing[7],we need to reduce the number of copy operations in order to get rea-sonable performance.However,unlike other performance-oriented research on network processors,our goal is not to enhance overall network performance,rather to pro-vide a standard interface to the network processor through which the network processor can provide various process-ing tasks.Eventually,we plan to investigate how our Linux im-plementation of the host-network processor interface ties into the structure of networking code in other operating sys-tems.We expect that other Unix implementations should coincide fairly well with the Linux implementation.The correlation to other proprietary operating systems may not be so close.We are also developing a next-generation CiNIC us-ing a FPGA design with an embedded soft-core proces-sor running Linux.This future platform will provide us with many hardware capabilities beyond that of the current Strong-ARM platform such as the ability to create auxil-iary processing blocks for special purposes.Along with development of our next-generation hardware,we plan to move from a polling communication protocol between the host and co-processor to an interrupt-driven communica-tion protocol.This approach will be facilitated by the new hardware and will relieve both the host and co-processor from supporting the busy-waiting kernel threads used in the polling protocol.6ConclusionsWe have described the implementation of a host-network processor interface that relies upon the traditional socket programming API.We implemented the interface in kernel space using loadable Linux kernel modules.The selection of the network protocol family fulfilled our design require-ments for the host-network processor interface by provid-ing a narrow point at which to terminate host processing. This interface allows network processing to proceed on the outboard platform with minimal synchronization overhead, and allows the network processor to look like a simple de-vice to the host operating system.References[1]C OOPER, E. C.,S TEENKISTE,P. A.,S ANSOM,R.D.,AND Z ILL,B.D.Protocol Implementation on the Nectar Communication Processor.In Proceedings of the SIGCOMM Symposium on Communications Ar-chitectures and Protocols(1990),ACM,pp.135–144.[2]G ALLATIN, A.,C HASE,J.,AND Y OCUM,K.Trapeze/IP:TCP/IP at near-gigabit speeds.In Proceed-ings of the USENIX’99Technical Conference(June 1999),pp.109–120.[3]G UTLEBER,J.,AND O RSINI,L.Architectural soft-ware support for processing clusters.In Proceedingsof the IEEE Int’l Conference on Cluster Computing (2000),pp.153–161.[4]H ATASHITA,J.,H ARRIS,J.,S MITH,H.,AND N ICO,P.An evaluation architecture for a network copro-cessor.In Proceedings of the2002IASTED Interna-tional Conference on Parallel and Distributed Comput-ing and Systems(PDCS)(November2002).[5]K AISERSWERTH,M.The Parallel Protocol Engine.IEEE/ACM Transactions on Networking1,6(1993), 650–663.[6]K ANAKIA,H.,AND C HERITON,D.R.The VMPnetwork adapter board(NAB):High-performance net-work communication for multiprocessors.In Proceed-ings of Sigcomm-88(1988),pp.175–187.[7]K LEINPASTE,K.,S TEENKISTE,P.,AND Z ILL,B.Software support for outboard buffering and check-summing.In Proceedings of the Conference on Ap-plications,Technologies,Architectures,and Protocols for Computer Communication(1995),pp.87–98. [8]S TEVENS,R.W.UNIX Network Programming.Pren-tice Hall,Englewood Cliffs,NJ,1990.。

思科基础知识：Cisco IOS简介Cisco IOS—路由器IOSIOS是被用来传送网络服务并启动网络应用的。

Cisco路由器的IOS软件负责完成重要的工作：加载网络协议和功能在设备间连接高速流量在控制访问中添加安全性防止未授权的网络使用为简化网络的增长和冗余备份，提供可缩放性为连接到网络中的资源，提供网络的可靠性Cisco IOS—连接到Cisco路由器可以通过连接到Cisco路由器来进行路由器的设置、配置的验证及统计数据的审核。

通常是使用通过控制台端口进行连接。

控制台接口一般是一个RJ-45的连接器，位于路由器背面，默认的时候，没有口令要求。

Cisco IOS—启动路由器初次启动一个Cisco路由器时，它将运行一个开机自检过程。

如果通过，他将在闪存中查找IOS系统，如果有IOS文件存在则执行装载操作。

闪存世一个电子可擦写变成的制度存储器。

然后，IOS将继续加载并查找一个合法的配置文件，它默认时是存储在NVRAM中。

当路由器被首次引导或重新装载时，会出现的信息：System Bootstrap, Version 11.0(10c), SOFTWARECopyright (c) 1986-1996 by cisco Systems2500 processor with 14336 Kbytes of main memory这是一台2501路由器启动时的信息：第一行写了，IOS版本是11.0，第二行是CISCO的版权信息，第三行行是内存的大小。

路由器启动以后，会出现一个提示：Would you like to enter the initial configuration dialog? [yes/no]: n如果选择yes，将进入setup模式，选择No我们将进入扩展设置模式。

Setup模式只配置购管理系统使用的连接性能，而扩展设置会允许你配置更多的内容。

Cisco IOS—命令行界面正式因为命令行界面（CLI）是如此的灵活方便，所以他是配置路由器的最佳方式。

绪论1.本课程采用“自顶向下”的方式讲解计算机网络原理。

答案:对第一章1.The web server is not an end system?答案:错2.The upper layers of the OSI model are ( )in correct order.答案:Session,presentation,application3.The lower layers of the OSI model are ( )in correct order.答案:physical,datalink,network,transport4.The Internet Protocol (IP) generally corresponds to which OSI layer?答案:Network(layer three)5.Which of these network devices primarily functions at the OSI Networklayer(layer 3)?答案:Router第二章1.TCP is an application layer protocol.答案:错2.Which is not an application layer protocol? ( )答案:ARP3.The only architecture of applications is peer-to-peer.答案:错4.In the client-server architecture, the clients is not always on.答案:对5.Mail server port number is ( )答案:25第三章1.The POP3 protocol runs over ____ and uses port ____.答案:TCP 1102.____ is most used for error reporting.答案:ICMP3.In the following options, which does not use UDP?答案:telnet4.Internet transport-layer protocols include TCP,IP and UDP.答案:错5.TCP sender perceive congestion through a timeout event or a receivingduplicate ACK-s event.答案:对第四章1.RARP protocol translates IP addresses into MAC addresses.答案:错2.The PING command is implemented by the ICMP echo request/reply.答案:对3.An IP address consists of a network number field and a host number field.答案:对4.The main task of the Internet’s Domain Name System (DNS) is to:答案:Translate mnemonic（记忆的） names to IP addresses5.The Internet’s network layer is responsible for moving network-layerpackets known as ( ) from one host to another.答案:datagram第五章1.MAC address is unique in the world.答案:对2. A 16-port switch,each port is 10/100M full-duplex adaptive,then busbandwidth of the switch is ( )答案:100M3.The switch receives a frame whose targe address cannot be found in its MACaddress table,then switch will do ( )答案:flooding4.What is true of the ARP table in the following description is?答案:mapping ofIP address to MAC address5.Which layer does the switch work on?答案:link layer第六章1.There are two address fields in 802.11 frame.答案:错2.What are the type of wireless networks?答案:Single hop, infrastructure-based;Multi-hop, infrastructure-based;Single hop, infrastructure-less;Multi-hop, infrastructure-less3.Hosts in wireless networks can work in two modes ( )答案:infrastructuremode;ad hoc mode4.APs transmit beacon frames. An AP’s beacon frames will be transmitted overone of the ( ) channels. The beacon frames permit nearby wireless stations to discover and identify the AP.答案:115.CDMA is a kind of ( ) protocol答案:random access。

排除网络的问题英语作文Title: Troubleshooting Network Issues。

In today's interconnected world, a stable and reliable network connection is essential for both personal and professional activities. However, encountering network issues can be frustrating and disruptive. When troubleshooting network problems, it's important to follow a systematic approach to identify and resolve the underlying issues effectively. Here are some steps to troubleshoot network problems without revealing any personal prompts:1. Check Physical Connections: The first step in troubleshooting network problems is to ensure that all physical connections are secure and properly connected. Check cables, wires, and connections to routers, modems, and devices to ensure there are no loose connections or damage.2. Restart Devices: Sometimes, network issues can be resolved by simply restarting the devices involved. Restart your computer, modem, router, and any other networking equipment to refresh their settings and establish a new connection.3. Verify Network Settings: Check the network settings on your devices to ensure they are configured correctly. Verify the IP address, subnet mask, gateway, and DNS settings to ensure they are appropriate for your network environment.4. Test Connectivity: Use built-in network diagnostic tools or third-party software to test connectivity between devices on your network and the internet. Ping tests, traceroute, and network scanning tools can help identify where connectivity issues are occurring.5. Check Firewall and Security Settings: Firewalls and security settings on your devices or network equipment can sometimes block network traffic and cause connectivity issues. Review and adjust firewall settings to allownecessary network traffic.6. Update Firmware and Drivers: Ensure that the firmware on your modem, router, and other networking devices is up to date. Similarly, update network drivers on your computer to ensure compatibility and stability.7. Consider Interference: Wireless networks can be susceptible to interference from other electronic devices, neighboring networks, and physical obstacles. Move wireless devices closer to the router, switch to a less congested wireless channel, or relocate devices to minimize interference.8. Check for Service Outages: Contact your internet service provider (ISP) to check for any known service outages in your area. Sometimes, network problems are due to issues on the ISP's end, which they need to address.9. Monitor Network Traffic: Use network monitoringtools to analyze network traffic and identify any abnormal patterns or bandwidth bottlenecks. This can help pinpointthe source of network problems and take appropriate action.10. Seek Professional Help: If you've exhausted all troubleshooting steps and are still experiencing network issues, consider seeking help from a professional network technician or your ISP's technical support team. They may have access to advanced diagnostic tools and expertise to resolve complex network problems.By following these steps and maintaining a systematic approach, you can effectively troubleshoot network issues without revealing any personal prompts. Remember to document your troubleshooting process and any changes made to network settings for future reference. With patience and persistence, most network problems can be resolved efficiently, ensuring a stable and reliable network connection.。