PC1配置：
No ip routing
interface FastEthernet0/0
ip address 172.16.20.254 255.255.255.0
No shutdown
PC2配置：
No ip routing
interface FastEthernet0/0
ip address 172.16.30.254 255.255.255.0
No shutdown
Switch配置：
Ip routing
interface FastEthernet0/1
switchport access vlan 20
no ip address
!
interface FastEthernet0/2
switchport access vlan 30
no ip address
!
Vlan database
Vlan 20
Vlan 30
Exit
!
interface Vlan20
ip address 172.16.20.1 255.255.255.0
No shutdown
!
interface Vlan30
ip address 172.16.30.1 255.255.255.0
No shutdown
===========================
验证：
PC1#ping 172.16.30.254 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.30.254, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 44/100/196 ms
PC2#ping 172.16.20.254 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.20.254, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 56/80/120 ms