交换机如何实现多网段互通

写在前面

问答平台看到这样一个问题，回答后所以顺便整理一下
一般情况下，三层交换机不直接连终端，太浪费了，可以连一个交换机然后再连终端

傍晚时分，你坐在屋檐下，看着天慢慢地黑下去，心里寂寞而凄凉，感到自己的生命被剥夺了。当时我是个年轻人，但我害怕这样生活下去，衰老下去。在我看来，这是比死亡更可怕的事。--------王小波

案例

需求：实验室有一条接入网线，该网线直接连接PC，PC的IP设置为 192.168.100.xxx 后可以访问服务器机房的服务器（IP为192.168.100.1），但是想要实验室内的多台PC都能访问 192.168.100.1，请问交换机应该如何配置？

拓扑图

设计拓扑图

拓扑图。配置

配置三层交换机

配置终端IP

ping测试

配置

配置三层交换机

在三层交换机LSW上创建VLAN

Please press enter to start cmd line! <Huawei>syst <Huawei>system-view Enter system view, return user view with Ctrl+Z. [Huawei]vlan batch 100 10 Info: This operation may take a few seconds. Please wait for a moment...done. [Huawei] Oct 16 2021 14:06:41-08:00 Huawei DS/4/DATASYNC_CFGCHANGE:OID 1.3.6.1.4.1.2011.5 .25.191.3.1 configurations have been changed. The current change number is 4, th e change loop count is 0, and the maximum number of records is 4095. [Huawei]quit <Huawei>undo terminal debugging Info: Current terminal debugging is off. <Huawei>undo terminal monitor Info: Current terminal monitor is off. <Huawei>undo terminal logging Info: Current terminal logging is off. <Huawei>undo terminal trapping Info: Current terminal trapping is off.

将接口加入到对应VLAN中

<Huawei>system-view Enter system view, return user view with Ctrl+Z. [Huawei]interface GigabitEthernet 0/0/1 [Huawei-GigabitEthernet0/0/1]port link-type access [Huawei-GigabitEthernet0/0/1]port default vlan 100 [Huawei-GigabitEthernet0/0/1]quit [Huawei]port-group 2 [Huawei-port-group-2]group-member GigabitEthernet 0/0/2 GigabitEthernet 0/0/3 [Huawei-port-group-2]port link-type access [Huawei-GigabitEthernet0/0/2]port link-type access [Huawei-GigabitEthernet0/0/3]port link-type access [Huawei-port-group-2]port default vlan 10 [Huawei-GigabitEthernet0/0/2]port default vlan 10 [Huawei-GigabitEthernet0/0/3]port default vlan 10 [Huawei-port-group-2]quit

在三层交换机上给VLAN配置网关

[Huawei]interface Vlanif 100 [Huawei-Vlanif100]ip address 192.168.100.254 24 [Huawei-Vlanif100]quit [Huawei]interface Vlanif 10 [Huawei-Vlanif10]ip address 192.168.10.254 24 [Huawei-Vlanif10]quit [Huawei]display ip routing-table | include /24 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 6 Routes : 6 Destination/Mask Proto Pre Cost Flags NextHop Interface 192.168.10.0/24 Direct 0 0 D 192.168.10.254 Vlanif10 192.168.100.0/24 Direct 0 0 D 192.168.100.254 Vlanif100 [Huawei]

配置终端

服务器

 PC>ipconfig Link local IPv6 address...........: fe80::5689:98ff:fea0:1eb4 IPv6 address......................: :: / 128 IPv6 gateway......................: :: IPv4 address......................: 192.168.100.1 Subnet mask.......................: 255.255.255.0 Gateway...........................: 192.168.100.254 Physical address..................: 54-89-98-A0-1E-B4 DNS server........................: PC>ping 192.168.10.2 Ping 192.168.10.2: 32 data bytes, Press Ctrl_C to break From 192.168.10.2: bytes=32 seq=1 ttl=127 time=110 ms From 192.168.10.2: bytes=32 seq=2 ttl=127 time=47 ms From 192.168.10.2: bytes=32 seq=3 ttl=127 time=46 ms --- 192.168.10.2 ping statistics --- 3 packet(s) transmitted 3 packet(s) received 0.00% packet loss round-trip min/avg/max = 46/67/110 ms

PC1

Welcome to use PC Simulator! PC>ipconfig Link local IPv6 address...........: fe80::5689:98ff:fea7:1ca1 IPv6 address......................: :: / 128 IPv6 gateway......................: :: IPv4 address......................: 192.168.10.2 Subnet mask.......................: 255.255.255.0 Gateway...........................: 192.168.10.254 Physical address..................: 54-89-98-A7-1C-A1 DNS server........................: PC>ping 192.168.100.1 Ping 192.168.100.1: 32 data bytes, Press Ctrl_C to break From 192.168.100.1: bytes=32 seq=1 ttl=127 time=47 ms From 192.168.100.1: bytes=32 seq=2 ttl=127 time=31 ms --- 192.168.100.1 ping statistics --- 2 packet(s) transmitted 2 packet(s) received 0.00% packet loss round-trip min/avg/max = 31/39/47 ms

PC2

PC>ipconfig Link local IPv6 address...........: fe80::5689:98ff:fe84:2ce2 IPv6 address......................: :: / 128 IPv6 gateway......................: :: IPv4 address......................: 192.168.10.3 Subnet mask.......................: 255.255.255.0 Gateway...........................: 192.168.10.254 Physical address..................: 54-89-98-84-2C-E2 DNS server........................: PC>ping 192.168.100.1 Ping 192.168.100.1: 32 data bytes, Press Ctrl_C to break Request timeout! From 192.168.100.1: bytes=32 seq=2 ttl=127 time=47 ms From 192.168.100.1: bytes=32 seq=3 ttl=127 time=47 ms From 192.168.100.1: bytes=32 seq=4 ttl=127 time=47 ms --- 192.168.100.1 ping statistics --- 4 packet(s) transmitted 3 packet(s) received 25.00% packet loss round-trip min/avg/max = 0/47/47 ms

一般的解决方案

综合组网

案例(更合理地使用三层交换机)：交换机、三层交换机、路由构建网络

需求：实验室有一条接入网线，该网线直接连接PC，PC的IP设置为 192.168.4.xxx 后可以访问服务器机房的服务器（IP为192.168.5.1），但是想要实验室内的多台PC都能访问 192.168.5.1，请问交换机应该如何配置？

综合组网

第一步：设计好网络拓扑结构；为了缓解三层交换机的压力，通常连接外部网路需要连接一个路由器。路由器的功能要比三成交换机强大。

第二步：在PC1、PC2 和 PC3 及PC4 中配置IP地址，子网掩码和网关；

PC1: IP地址：192.168.1.1/24 网关：192.168.1.254 PC2: IP地址：192.168.2.1/24 网关：192.168.2.254 PC3: IP地址：192.168.3.1/24 网关：192.168.3.254 PC4: IP地址：192.168.5.1/24 网关：192.168.5.254

第三步：在二层交换机 (S3700) LSW1上创建VLAN；

<LSW1>system-view [LSW1]vlan batch 2 to 3 #二层交换机上创建vlan

第四步：将接口加入到交换机 (S3700) LSW1相应的vlan中；

[LSW1]interface Ethernet 0/0/2 [LSW1-Ethernet0/0/2]port link-type access [LSW1-Ethernet0/0/2]port default vlan 2 [LSW1-Ethernet0/0/2]display vlan #查看结果 [LSW1]interface Ethernet 0/0/3 [LSW1-Ethernet0/0/3]port link-type access [LSW1-Ethernet0/0/3]port default vlan 3 [LSW1-Ethernet0/0/3]display vlan #查看结果

第五步：在二层交换机LSW1 (S3700) 和三层交换机LSW2(S5700) 上配置trunk（中继链路）

#在二层交换机LSW1 (S3700)的Ethernet 0/0/4接口配置trunk [LSW1]interface Ethernet 0/0/4 [LSW1-Ethernet0/0/4]port link-type trunk [LSW1-Ethernet0/0/4]port trunk allow-pass vlan all [LSW1-Ethernet0/0/4]quit [LSW1]display current-configuration #在三层交换机LSW2(S5700)的Ethernet 0/0/4接口配置trunk [LSW2]interface GigabitEthernet 0/0/1 [LSW2-GigabitEthernet0/0/1]port link-type trunk [LSW2-GigabitEthernet0/0/1]port trunk allow-pass vlan all [LSW2-GigabitEthernet0/0/1]quit [LSW2]display current-configuration

第六步：在三层交换机LSW2(S5700)上创建vlan，并将接口GE 0/0/2加入到vlan 4中

<LSW2>system-view [LSW2]vlan batch 2 to 4 #三层交换机上创建vlan [LSW2]interface GigabitEthernet 0/0/2 [LSW2-GigabitEthernet0/0/2]port link-type access [LSW2-GigabitEthernet0/0/2]port default vlan 4 [LSW2-GigabitEthernet0/0/2]display vlan #查看结果

第七步：在三层交换机 LSW2(S5700) 的虚接口上配置IP

#在vlan 1上配置IP地址 [LSW2]interface Vlanif 1 [LSW2-Vlanif1]ip address 192.168.1.254 24 [LSW2-Vlanif1]quit #在vlan 2上配置IP地址 [LSW2]interface Vlanif 2 [LSW2-Vlanif2]ip address 192.168.2.254 24 [LSW2-Vlanif2]quit #在vlan 3上配置IP地址 [LSW2]interface Vlanif 3 [LSW2-Vlanif3]ip address 192.168.3.254 24 [LSW2-Vlanif3]quit #在vlan 4上配置IP地址 [LSW2]interface Vlanif 4 [LSW2-Vlanif4]ip address 192.168.4.1 24 [LSW2-Vlanif4]quit [LSW2]display ip routing-table | include /24 #查看虚接口配置信息

第八步：在路由器AR1(AR2220) 上给接口配置IP地址

<AR1>system-view [AR1]interface GigabitEthernet 0/0/0 [AR1-GigabitEthernet0/0/0]ip address 192.168.4.2 24 [AR1]interface GigabitEthernet 0/0/1 [AR1-GigabitEthernet0/0/1]ip address 192.168.5.254 24 #在路由器上给5.0网段配置网关 [AR1]display ip routing-table | include /24 #查看接口IP地址配置信息

第九步：在三层交换机LSW2(S5700)上配置静态路由

<LSW2>system-view [LSW2]ip route-static 192.168.5.0 24 192.168.4.2 #目标网段，子网掩码，下一跳地址 [LSW2]display ip routing-table | include /24

第十步：在路由器AR1(AR2220) 上配置静态路由

<AR1>system-view [AR1]ip route-static 192.168.1.0 24 192.168.4.1 #目标网段，子网掩码，下一跳地址 [AR1]ip route-static 192.168.2.0 24 192.168.4.1 [AR1]ip route-static 192.168.3.0 24 192.168.4.1 [AR1]display ip routing-table | include /24

第十一步：测试，保持全网互通

责任编辑: 鲁达

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