话不多说，先上图。

说明：路由器为AR2200,交换机为E3300，PC1,2,3分别属于vlan10 20 30 ，然后PC要从路由器端通过DHCPrelay的方式获取IP地址。

图中PC获取地址的方式是DHCP select relay,为什么是dhcp select relay呢？是因为PC的网关在交换机上，而地址池在AR路由器上。

当你选择DHCP select global的方式的时候，网关和地址池要在同一设备才可以的。

ARI配置

#
 undo info-center enable
#
vlan batch 10 20 30
#
dhcp enable
#
ip pool vlan10
 gateway-list 192.168.10.254 
 network 192.168.10.0 mask 255.255.255.0 
#
ip pool vlan20
 gateway-list 192.168.20.254 
 network 192.168.20.0 mask 255.255.255.0 
#
ip pool vlan30
 gateway-list 192.168.30.254 
 network 192.168.30.0 mask 255.255.255.0 
#

#
interface GigabitEthernet0/0/0
 ip address 192.168.2.1 255.255.255.0 
 dhcp select global

#
ip route-static 192.168.2.0 255.255.255.0 192.168.2.254
ip route-static 192.168.10.0 255.255.255.0 192.168.2.254
ip route-static 192.168.20.0 255.255.255.0 192.168.2.254
ip route-static 192.168.30.0 255.255.255.0 192.168.2.254
#

S交换机配置

#
undo info-center enable
#
vlan batch 10 20 30
#
#
dhcp enable
#

#
interface Vlanif1
 ip address 192.168.2.254 255.255.255.0
#
interface Vlanif10
 ip address 192.168.10.254 255.255.255.0
 dhcp select relay
 dhcp relay server-ip 192.168.2.1
#
interface Vlanif20
 ip address 192.168.20.254 255.255.255.0
 dhcp select relay
 dhcp relay server-ip 192.168.2.1
#
interface Vlanif30
 ip address 192.168.30.254 255.255.255.0
 dhcp select relay
 dhcp relay server-ip 192.168.2.1
#
interface Ethernet0/0/2
 port link-type access
 port default vlan 10
#
interface Ethernet0/0/3
 port link-type access
 port default vlan 20
#
interface Ethernet0/0/4
 port link-type access
 port default vlan 30
#
#
ip route-static 0.0.0.0 0.0.0.0 192.168.2.1
#