Ether Channel Configuration Help

[Jacob Samuel]

Hi Friends,

I have a similer configuration like mentione below in one another customer site. There the trunk was working fine and ether channel too. But once i removed the Fiber cable from one switch and tried to put it back.. the ether channel was not coming up... i tried to do shut and no shut at both side but again it was showing down.

Can any one tell me what could eb the problem in this?? both the side i used "channel-group 1 mode active" is that the problem???

thanks in advance..

regards

Jacob

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3550-12SD - Distribution Switch

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

interface Port-channel1

switchport trunk encapsulation dot1q

no ip address

!

interface GigabitEthernet0/9

description *** Up-Link to Core Switch on Gig 2/15 ***

switchport trunk encapsulation dot1q

no ip address

channel-group 1 mode active

!

interface GigabitEthernet0/10

description *** Up-Link to Core Switch on Gig 2/16 ***

switchport trunk encapsulation dot1q

no ip address

channel-group 1 mode active

6503 core switch

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

interface Port-channel1

switchport

switchport trunk encapsulation dot1q

no ip address

!

interface GigabitEthernet2/15

description *** Up-Link to New Bldg Distribution switch on Gig 0/9 ***

switchport

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

channel-group 1 mode active

!

interface GigabitEthernet2/16

description *** Up-Link to New Bldg Distribution switch on Gig 0/10 ***

switchport

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

channel-group 1 mode active

!

[vishwancc]

Hi Jacob,

Could you post the output of show int gi2/15 and 16 switchport and interface GigabitEthernet0/9 switchport

try channel-group 1 mode on remember to shut the port when doing this and then no shut.

Chao

Vishwa

[Jacob Samuel]

I am sorry, i was in a customer site at that time. I dont have any outputs for the same.

This was not become as an issue since I changed the connection from the distribution to that switch in server farm and put it on the ASA, as per the design it is like that.

But i was observing this problem. since I have some other network which running same like this configuration.

what could be the possible issues?

regards

Jacob

[viyuan700]

you have only defined encapsulation method for interface GigabitEthernet0/9 and interface GigabitEthernet0/10 on your distribution switch

You also have to define that they are trunk like your core switch. See the difference between the config for your core and distribution switch.

This command is miisng from your distribution switch

switchport mode trunk

[Jacob Samuel]

Hi Viswa,

I remember i applied this command on both the interfaces but why its not showing in the running config ? i will chk that later.

more oever I think the command switchport mode trunk is to make the trunk link up. in this case the configuration is a working one at one client site. both the trunk and l2 ether channel are working perfectly fine. If i missed this command he trunk will never come up.

Thanks

regards

Jacob

[viyuan700]

Can u check following commands, to check what protocol r u using

show etherchannel 1 port-channel

show channelprotocol

"both the side i used "channel-group 1 mode active" is that the problem??? " as this works with LACP did u set channel protocol

[Jacob Samuel]

Hi

I didnt set channel protocol command, no manual configuration, i think from cisco12.1(13) its support LACP. And think the default is also LACP now.

please correct if i miss something at this part.

Thanks & regards

Jacob

[viyuan700]

"interface GigabitEthernet0/9

description *** Up-Link to Core Switch on Gig 2/15 ***

switchport trunk encapsulation dot1q

no ip address

channel-group 1 mode active

!

interface GigabitEthernet0/10

description *** Up-Link to Core Switch on Gig 2/16 ***

switchport trunk encapsulation dot1q

no ip address

channel-group 1 mode active "

If the above is correct then you have not defined the below command both ports

switchport mode trunk