两台3750G做双线路port-channel

From:http://hi.baidu.com/wen20051141/blog/item/ef20380386f95f01738b650c.html

两台3750G，之前单线跑access 模式，由于有多个网段通过核心交换的需求，需要做成trunk模式，在实施单线trunk的过程中，很顺利。

SW1:

conf t

int port-channel 1

进入接口模式

int port-channel 1

sw tr en dot

sw mode trun

int g1/0/12

sw trunk en dot

sw mode trunk

channel-group 1 mode on

int g1/0/24

sw trunk en dot

sw mode trunk

channel-group 1 mode on

=======================================================================================

SW2:

conf t

int port-channel 1

进入接口模式

int port-channel 1

sw tr en dot

sw mode trun

int g1/0/23

sw trunk en dot

sw mode trunk

channel-group 1 mode on

int g1/0/24

sw trunk en dot

sw mode trunk

channel-group 1 mode on

到此，两边应该就都通了，show ip int brief ，应该会看到一个虚的port-channel 1 的接口，是up的。

============================================================================================

但是昨天晚上在实施的时候，没有事先把端口归进 group组，出现了环路，在其中一台核心3750G上面出现了如下的报错：

1 is flapping between port Po1 and port Gi1/0/3

*May 11 09:55:48.371 GMT: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.c9b2.3541 in vlan

1 is flapping between port Gi1/0/3 and port Po1

*May 11 09:55:48.397 GMT: %PM-4-ERR_DISABLE: channel-misconfig error detected on

Gi1/0/12, putting Gi1/0/12 in err-disable state

*May 11 09:55:48.413 GMT: %PM-4-ERR_DISABLE: channel-misconfig error detected on

Gi1/0/24, putting Gi1/0/24 in err-disable state

*May 11 09:55:49.412 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Gigabi

tEthernet1/0/12, changed state to down

*May 11 09:55:49.428 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Gigabi

tEthernet1/0/24, changed state to down

*May 11 09:55:49.428 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-c

hannel1, changed state to down

*May 11 09:55:49.445 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2,

changed state to down

*May 11 09:55:49.445 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan10

, changed state to down

*May 11 09:55:50.418 GMT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/12, chang

ed state to down

*May 11 09:55:50.443 GMT: %LINK-3-UPDOWN: Interface Port-channel1, changed state

to down

*May 11 09:55:50.443 GMT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/24, chang

ed state to down

可以看出，两个口子，已经全部被STP给down掉了，进接口一看，全是error-disable状态，于是，在理清了思路以后，把端口归进channel-group 1 的组，把接口shut,接着no shut，到此，故障解决，两台交换机一切正常，实现了线路冗余与带宽扩容。