单臂路由:
通过路由子接口，交换机的某个端口（f0/10）以trunk的方式与路由器的某个端口(f0/0)相连，同时路由器的链接端口配置子接口，配置子接口承载的vlan（vlan 1,vlan 2）.此时链接在交换机不同vlan (vlan 1, vlan 2)接口上的 设备即可相互通信,
三层交换:
三层交换机路由属于直通路由. 在交换机的 ip route table中的vlan可以直接通信，只需要开启路由器的路由功能.
Switch>show ip rout
Switch>show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.1.0/24 is directly connected, Vlan100
C 192.168.2.0/24 is directly connected, Vlan101
Switch>
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