不同网段之间数据访问需要路由信息（路由表），路由就是通往目标的路径。路由表中有三种路由：直连路由、静态路由、动态路由。
直连路由一半只要在路由器接口配上ip地址，物理与协议都是up状态就可建立，不需要网络人员维护，但是直连路由无法获取与其不直接相邻的路由信息。直连路由是所有路由协议中优先级最高的
一、直连路由实际效果拓扑图
二、路由器接口ip地址基础配置
①、AR1路由器接口ip配置
<H3C>sys System View: return to User View with Ctrl+Z. [H3C]sysname AR1 [AR1]interface GigabitEthernet 0/0 #进入接口视图 [AR1-GigabitEthernet0/0]ip address 192.168.10.1 24 #配置ip地址 [AR1-GigabitEthernet0/0]quit
[AR1]interface GigabitEthernet 0/1
[AR1-GigabitEthernet0/1]ip add
[AR1-GigabitEthernet0/1]ip address 192.168.30.1 24
[AR1]quit
<AR1>sys
System View: return to User View with Ctrl+Z. [AR1]interface Loo [AR1]interface LoopBack 0 #进入环回接口视图 [AR1-LoopBack0]ip address 10.10.10.1 32 #环回接口配置ip地址 [AR1-LoopBack0]quit [AR1]quit <AR1>save The current configuration will be written to the device. Are you sure? [Y/N]:Y Please input the file name(*.cfg)[flash:/startup.cfg] (To leave the existing filename unchanged, press the enter key): Validating file. Please wait... Configuration is saved to device successfully.
查看AR1接口配置信息：display ip interface brief
注意点：环回接口是无法手动关闭的，物理接口可以关闭。
[AR1]interface GigabitEthernet 0/0 #进入接口 [AR1-GigabitEthernet0/0]shutdown #shutdown命令关闭接口 [AR1-GigabitEthernet0/0]%Jun 16 15:07:20:347 2023 AR1 IFNET/3/PHY_UPDOWN: Physical state on the interface GigabitEthernet0/0 changed to down. %Jun 16 15:07:20:347 2023 AR1 IFNET/5/LINK_UPDOWN: Line protocol state on the interface GigabitEthernet0/0 changed to down. [AR1-GigabitEthernet0/0]display this #display this 查看接口装状态显示shutdown interface GigabitEthernet0/0 port link-mode route combo enable copper shutdown ip address 192.168.10.1 255.255.255.0 # return [AR1-GigabitEthernet0/0]undo shutdown #重新打开接口 [AR1-GigabitEthernet0/0]%Jun 16 15:07:56:433 2023 AR1 IFNET/3/PHY_UPDOWN: Physical state on the interface GigabitEthernet0/0 changed to up. %Jun 16 15:07:56:433 2023 AR1 IFNET/5/LINK_UPDOWN: Line protocol state on the interface GigabitEthernet0/0 changed to up. [AR1-GigabitEthernet0/0]display this # interface GigabitEthernet0/0 port link-mode route combo enable copper ip address 192.168.10.1 255.255.255.0 # return [AR1-GigabitEthernet0/0]
②、 AR2路由器接口ip配置
[H3C]sysname AR2 [AR2]interface GigabitEthernet 0/0 [AR2-GigabitEthernet0/0]ip address 192.168.10.2 24 [AR2-GigabitEthernet0/0]quit [AR2]interface GigabitEthernet 0/1 [AR2-GigabitEthernet0/1]ip address 192.168.20.2 24 [AR2-GigabitEthernet0/1]quit [AR2]interface LoopBack 0 [AR2-LoopBack0]ip address 20.20.20.2 32 [AR2-LoopBack0]quit [AR2]quit <AR2>save
查看AR2接口配置信息
③、AR3路由器接口ip配置
[H3C]sysname AR3 [AR3]interface GigabitEthernet 0/0 [AR3-GigabitEthernet0/0]ip address 192.168.20.3 24 [AR3-GigabitEthernet0/0]quit [AR3]interface GigabitEthernet 0/1 [AR3-GigabitEthernet0/1]ip address 192.168.40.1 24 [AR3-GigabitEthernet0/1]quit [AR3]interface LoopBack 0 [AR3-LoopBack0]ip address 30.30.30.3 32 [AR3-LoopBack0]quit [AR3]quit <AR3>save The current configuration will be written to the device. Are you sure? [Y/N]:Y Please input the file name(*.cfg)[flash:/startup.cfg] (To leave the existing filename unchanged, press the enter key): Validating file. Please wait... Configuration is saved to device successfully. <AR3>
查看AR3接口配置信息
④、PC1、PC2配置
⑤、直连路由通信测试
AR1：192.168.10.1 AR2：192.168.10.2 AR3：192.168.20.3
PC1：192.168.30.10 PC2：192.168.40.10
AR1 ping AR2
AR1 ping PC1
AR2 ping AR3
注意点：PC1 ping PC2 是不通的
直连路由无法跨设备通信，要实现全网互通需要手工配置静态以及动态路由协议。
补充：查看AR1的直连路由信息，其他路由器自行查看。
Destination/Mask：目标网段以及子网掩码，例如192.168.10.1/24
Proto:显示路由条目的类型。直连路由Direct，静态路由Static，动态路由RIP、OSF
Pre：数值越小，优先级别越高。默认情况下，直连路由是0，静态路由是60.
Cost：去往同一网络不同的路由，路由器会根据cost判断出最优的路径，cost越小，优先级别越高。
NextHop：下一跳ip地址，相邻设备接口的ip地址。
interface：出接口，从设备的该接口转发数据。
