下面开始
1，不同VLAN通过三层交换通信 2，配置路由器DHCP功能，使得pc机能够自动获得ip地址
SW1：
SW1#vlan database
SW1(vlan)#vlan 10
SW1(vlan)#vlan 20
SW1(vlan)#vtp domain ccb
SW1(vlan)#vtp server
SW1(config)#interface fa0/1
SW1(config-if)#switchport mode trunk
SW1(config-if)#switchport trunk encapsulation dot1q
SW1(config)#interface fa0/2
SW1(config-if)#switchport mode trunk
SW1(config-if)#switchport trunk encapsulation dot1q
interface Vlan10
ip address 192.168.10.1 255.255.255.0
!
interface Vlan20
ip address 192.168.20.1 255.255.255.0
SW2(config)#interface fa0/1
SW2(config-if)#switchport mode trunk
SW2(config-if)#switchport trunk encapsulation dot1q
SW2#vlan database
SW2(vlan)#vtp domain ccb
SW2(vlan)#vtp client
SW2(config)#interface fa0/0
SW2(config-if)#switchport mode acc
SW2(config-if)#switchport access vlan 10
SW3(config)#interface fa0/2
SW3(config-if)#switchport mode trunk
SW3(config-if)#switchport trunk encapsulation dot1q
SW3#vlan database
SW3(vlan)#vtp domain ccb
SW3(vlan)#vtp client
SW3(config)#interface fa0/0
SW3(config-if)#switchport mode acc
SW3(config-if)#switchport access vlan 20
SW2#sh vlan-switch
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/2, Fa0/3, Fa0/4, Fa0/5
Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13
Fa0/14, Fa0/15
10 VLAN0010 active Fa0/0
20 VLAN0020 active
SW3#sh vlan-switch
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/3, Fa0/4, Fa0/5
Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13
Fa0/14, Fa0/15
10 VLAN0010 active
20 VLAN0020 active Fa0/0
下面在PC上配上ip地址测试vlan间的路由
PC1(config)#no ip routing
PC1(config)#interface fa0/0
PC1(config-if)#ip add 192.168.10.11 255.255.255.0
PC1(config)#ip default-gateway 192.168.10.1
PC2(config)#no ip routing
PC2(config)#interface fa0/0
PC2(config-if)#ip add 192.168.20.11 255.255.255.0
PC2(config)#ip default-gateway 192.168.20.1
PC1#ping 192.168.20.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.11, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/54/104 ms
vlan间已经通过三层交换通信，下面在路由器上配置DHCP,让PC机子自动获取IP,排除部分地址，更能看出效果
routerA:
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp excluded-address 192.168.20.1 192.168.20.10
!
ip dhcp pool vlan10
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
!
ip dhcp pool vlan20
network 192.168.20.0 255.255.255.0
default-router 192.168.20.1
!
路由器和三层交换机启用ospf路由协议,PC和路由器之间能够通信
routerA:
interface FastEthernet0/0
ip address 192.168.30.1 255.255.255.0
duplex auto
speed auto
!
router ospf 10
log-adjacency-changes
network 192.168.30.0 0.0.0.255 area 0
SW1:
interface FastEthernet0/0
no switchport
ip address 192.168.30.2 255.255.255.0
router ospf 10
log-adjacency-changes
network 192.168.10.0 0.0.0.255 area 0
network 192.168.20.0 0.0.0.255 area 0
network 192.168.30.0 0.0.0.255 area 0
PC1#ping 192.168.30.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.30.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/252/1060 ms
需要把PC设置成自动获取IP
PC1(config)#interface fa0/0
PC1(config-if)#no ip add
PC1(config-if)#ip add dhcp
PC1(config-if)#exit
PC1(config)#no ip default-gateway
PC2(config)#interface fa0/0
PC2(config-if)#no ip add
PC2(config-if)#ip add dhcp
PC2(config-if)#exit
PC2(config)#no ip default-gateway
上面已经配置了，但是不能获得IP地址，因为还需要ip helper-address 命令，因为三层交换机隔离广播，所以需要指定请求地址
SW1(config)#interface vlan 10
SW1(config-if)#ip helper-address 192.168.30.1
SW2(config)#interface vlan 20
SW2(config-if)#ip helper-address 192.168.30.1
下面看一下 PC1和PC2 获得的IP地址
PC1#sh ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.10.11 YES DHCP up up
PC2#sh ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.20.11 YES DHCP up up
PC1#ping 192.168.20.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.11, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/272/1168 ms
