实验简介：如果有2条路的话可形成环路，开启生成树，则浪费掉一条路，可惜了
绑定后，可以让两条路由共同承担流量
实验过程：
第一步：在sw1上配置

sw1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
sw1(config)#int ran f0/23 -24
sw1(config-if-range)#switchport trunk encapsulation dot1q
sw1(config-if-range)#sw mode trunk
sw1(config-if-range)#channel-group 2 mode on
第二步：在sw2上配置

sw2(config)#int ran f0/23 -24
sw2(config-if-range)#sw trunk encapsulation dot1q
sw2(config-if-range)#switchport mo trunk
sw2(config-if-range)#channel-group 2 mode on
第三步在sw1上查看

sw1#sh et su
Flags: D - down P - in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
U - in use f - failed to allocate aggregator
u - unsuitable for bundling
w - waiting to be aggregated
d - default port

Number of channel-groups in use: 2
Number of aggregators: 2

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
2 Po2(SU) - Fa0/23(P) Fa0/24(P)
第四步：在sw2上查看

sw2#sh etherchannel su
sw2#sh etherchannel summary
Flags: D - down P - in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
U - in use f - failed to allocate aggregator
u - unsuitable for bundling
w - waiting to be aggregated
d - default port

Number of channel-groups in use: 2
Number of aggregators: 2

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
2 Po2(SU) - Fa0/23(P) Fa0/24(P)