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New Member

Etherchannel Prob

Hey Folks,

I'm trying to etherchannel ports Fa0/1 and Fa0/2 on two 3550's. Here's my etherchannel config:

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 99-1005

no ip address

no shutdown

!

interface FastEthernet0/1

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

!

interface FastEthernet0/2

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

!

Problem: The ports are not bundling and therefore not forming an etherchannel. The etherchannel is in the "suspend" mode and reports this error: Probable reason: vlan mask is different.

Anyone see's what's wrong?

-RER

2 ACCEPTED SOLUTIONS

Accepted Solutions
VIP Purple

Re: Etherchannel Prob

Hello,

I think the problem comes from the fact that you are allowing differnt VLANs on your port channel interface than on your member interfaces. mae sure your config looks like this:

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

--> switchport trunk allowed vlan 1,199-800

no ip address

no shutdown

!

interface FastEthernet0/1

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

!

interface FastEthernet0/2

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

HTH,

GP

Re: Etherchannel Prob

As far as I know, all settings must be identical for the channel and the interfaces in it. I noticed that on the channel interface you are allowing a set of vlans that is different from the two physical interfaces. This is a likely explanation for the error you are getting.

Besides, I would prefer to fix the channel setting either to trunk or access-mode, no dynamic stuff here.

Regards,

Leo

Regards,

Leo

3 REPLIES
VIP Purple

Re: Etherchannel Prob

Hello,

I think the problem comes from the fact that you are allowing differnt VLANs on your port channel interface than on your member interfaces. mae sure your config looks like this:

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

--> switchport trunk allowed vlan 1,199-800

no ip address

no shutdown

!

interface FastEthernet0/1

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

!

interface FastEthernet0/2

no spanning-tree portfast

switchport access vlan 1

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

switchport trunk allowed vlan 1,199-800

no ip address

duplex full

speed 100

channel-group 1 mode desirable

logging event link-status

snmp trap link-status

cdp enable

no shutdown

HTH,

GP

Re: Etherchannel Prob

As far as I know, all settings must be identical for the channel and the interfaces in it. I noticed that on the channel interface you are allowing a set of vlans that is different from the two physical interfaces. This is a likely explanation for the error you are getting.

Besides, I would prefer to fix the channel setting either to trunk or access-mode, no dynamic stuff here.

Regards,

Leo

Regards,

Leo

New Member

Re: Etherchannel Prob

Doing a "switchport trunk allowed vlan 1,199-800" on Int Po1 fixed the problem, thanks folks.

-RER

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