Cisco简单配置（九）—三层交换机

article/2025/9/16 2:17:55

三层交换机就是具有部分路由功能的交换机，工作在OSI网络标准模型的第三层：网络层。三层交换机的最重要目的是加快大型局域网内部的数据交换，所具有的路由功能也是为这目的服务的，能够做到一次路由，多次转发。

一般会将三层交换机用在网络的核心层，用三层交换机连接不同的子网或VLAN。

三层交换机的重要的目的是加快大型局域网内部的数据交换，所具备的路由功能也多是围绕这一目的而展开的，所以它的路由功能没有同一档次的专业强

三层交换机就是二层技术加三层技术

IP编址
MLS	VLAN 10	192.168.10.254	255.255.255.0
	VLAN 20	192.168.20.254	255.255.255.0
	VLAN 30	192.168.30.254	255.255.255.0
	VLAN 40	192.168.99.254	255.255.255.0
	G0/1	192.168.200.254	255.255.255.252
	G0/2	209.165.200.225	255.255.255.252
S1	VLAN 99	192.168.99.1	255.255.255.0
S2	VLAN 99	192.168.99.2	255.255.255.0
S3	VLAN 99	192.168.99.3	255.255.255.0
PC1		192.168.10.1	255.255.255.0
PC2		192.168.20.1	255.255.255.0
PC3		192.168.30.1	255.255.255.0
PC4		192.168.10.2	255.255.255.0
PC5		192.168.20.2	255.255.255.0
PC6		192.168.30.2	255.255.255.0

Switch>enable
Switch#configure 
Switch(config)#hostname S1
S1(config)#vlan 10
S1(config-vlan)#vlan 20
S1(config-vlan)#vlan 30
S1(config)#vlan 99
S1(config-vlan)#vlan 999
S1(config-vlan)#exit
S1(config)#interface fastEthernet 0/1
S1(config-if)#switchport mode trunk 
S1(config-if)#switchport trunk native vlan 999
S1(config)#interface fastEthernet 0/2
S1(config-if)#switchport mode trunk 
S1(config-if)#switchport trunk native vlan 999
S1(config)#interface gigabitEthernet 0/1
S1(config-if)#switchport mode trunk

Switch>enable
Switch#configure 
Switch(config)#hostname S2
S2(config)#vlan 10
S2(config-vlan)#vlan 20
S2(config-vlan)#vlan 30
S2(config-vlan)#vlan 99
S2(config-vlan)#vlan 999
S2(config-vlan)#exit
S2(config)#interface fastEthernet 0/3
S2(config-if)#switchport mode access 
S2(config-if)#switchport access vlan 10
S2(config-if)#exit
S2(config)#interface fastEthernet 0/13
S2(config-if)#switchport mode access
S2(config-if)#switchport access vlan 20
S2(config-if)#exit
S2(config)#interface fastEthernet 0/23
S2(config-if)#switchport mode access 
S2(config-if)#switchport access vlan 30
S2(config-if)#exit
S2(config)#interface fastEthernet 0/1
S2(config-if)#switchport mode trunk 
S2(config-if)#switchport trunk native vlan 999

Switch>enable 
Switch#configure 
Switch(config)#hostname S3
S3(config)#vlan 10
S3(config-vlan)#vlan 20
S3(config-vlan)#vlan 30
S3(config-vlan)#vlan 99
S3(config-vlan)#vlan 999
S3(config-vlan)#exit
S3(config)#interface fastEthernet 0/3
S3(config-if)#switchport mode access 
S3(config-if)#switchport access vlan 10
S3(config-if)#exit
S3(config)#interface fastEthernet 0/13
S3(config-if)#switchport mode access 
S3(config-if)#switchport access vlan 20
S3(config-if)#exit
S3(config)#interface fastEthernet 0/23
S3(config-if)#switchport mode access 
S3(config-if)#switchport access vlan 30
S3(config-if)#exit
S3(config)#interface fastEthernet 0/2
S3(config-if)#switchport mode trunk 
S3(config-if)#switchport trunk native vlan 999

配置第 3 层交换

Switch>enable 
Switch#configure 
Switch(config)#hostname MLS
MLS(config)#interface gigabitEthernet 0/2
MLS(config-if)#no switchport 
MLS(config-if)#ip address 209.165.200.225 255.255.255.252
MLS(config-if)#no shutdown 
MLS(config-if)#exit
MLS(config)#vlan 10
MLS(config-vlan)#vlan 20
MLS(config-vlan)#vlan 30
MLS(config-vlan)#vlan 99
MLS(config-vlan)#exit
MLS(config)#interface vlan 10
MLS(config-if)#ip address 192.168.10.254 255.255.255.0
MLS(config-if)#exit
MLS(config)#interface vlan 20
MLS(config-if)#ip address 192.168.20.254 255.255.255.0
MLS(config-if)#exit
MLS(config)#interface vlan 30
MLS(config-if)#ip address 192.168.30.254 255.255.255.0
MLS(config-if)#exit
MLS(config)#interface vlan 99
MLS(config-if)#ip address 192.168.99.254 255.255.255.0
MLS(config-if)#exit