Etherchannel 分为二层和三层etherchannel
以太网链路捆绑用来增加带宽和负载均衡。拓扑如下:
Etherchannel的配置_第1张图片
SW1的配置:
interface FastEthernet0/1
channel-group 1 mode desirable
switchport mode trunk
interface FastEthernet0/2
channel-group 1 mode desirable
switchport mode trunk
interface Port-channel 1
switchport mode trunk
SW2的配置:
interface FastEthernet0/1
channel-group 1 mode desirable
switchport mode trunk
interface FastEthernet0/2
channel-group 1 mode desirable
switchport mode trunk
interface Port-channel 1
switchport mode trunk
show etherchannel summary 查看以太网通道的状态
SW2#show 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: 1
Number of aggregators: 1
Group Port-channel Protocol Ports
------+-------------+-----------+----------------------------------------------
1 Po1(SU) PAgP Fa0/1(P) Fa0/2(P)
S代表的是二层以太网通道 U代表UP 通道起来了 P代表这两个接口参与了以太网通道
注意的是:逻辑接口的配置会覆盖物理接口上的配置

这样就看到效果了吧!
另外要注意以太网通道的模式


etherchannel 的模式:

1、PAGP的模式:
on:不进行协商,没有协商traffic。类似nonegotiate
auto:passive negotiat state。可接受对端发出的协商,但不会主动申请。(默认)
desirable:active negotiat state。主动协商状态。主动发送PAGP包。
2、LACP的模式:
passive:passive negotiating state。被动状态,可接受。但不会主动申请(默认)
active:active negotiating state。主动状态,主动申请。
注意:
on on OK
desirable desirable OK
desirable auto OK
auto auto 形成不了
auto on 形成不了
active active OK
passive active OK
passive passive 形成不了