Port Channel issue Cisco 3850

[mediaos718]

I have a port-channel with 4 interfaces. One of the interfaces is flapping. What is weird is that it works for a few hours then it starts flapping then it is suppended. See error msg in the log below:

is not compatible with Gi1/0/5 and will be suspended (speed of Gi2/0/10 is 100M, Gi1/0/5 is 1000M

[Derrick Hurley · Accepted solution]

Check the "show interface" of the interfaces on both sides of the link.  I suspect you have a bad cable or SFP and you'll find input and CRC errors on the port.

[mediaos718]

Ok, I notice the CRC error (Very high) - I will change the SFP and go from there.

Thanks

[Derrick Hurley]

Great!  Come back and let us know how it goes.

[Julio E. Moisa]

Hi

You cannot create EtherChannel with different features or capabilities, You need to have same characteristics, speed, duplex etc.  

is not compatible with Gi1/0/5 and will be suspended (speed of Gi2/0/10 is 100M, Gi1/0/5 is 1000M

You should have the same speed on both interfaces 100 or 1000Mbps and the same at the other end.

Other cases are:

You cannot create an Etherchannel with FastEthernet on one switch and the other switch with GigaEthernet.

Also you cannot group FastEthernet and GigaEthernet ports on the same switch to build and Etherchannel. 

Hope it is useful

:-)

[mediaos718]

@Julio E. Moisa

The ports are all GigabitEthernet - Sometimes it works for a couple of hours. I just swapped the SFP - Everything is working (See log below). I am going to wait for a couple of hours to see if the flapping continues.

*Sep 29 05:07:45.593 EDT: %EC-5-COMPATIBLE: Gi2/0/10 is compatible with port-channel members

*Sep 29 05:07:45.683 EDT: %EC-5-COMPATIBLE: Gi2/0/10 is compatible with port-channel members

*Sep 29 05:07:47.585 EDT: %LINK-3-UPDOWN: Interface GigabitEthernet2/0/10, changed state to up

*Sep 29 05:07:51.295 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet2/0/10, changed state to up

[Julio E. Moisa]

Thank you,

Could you please share the configuration of the Portchannel members and interface port channel from both switches.

Thank you 

[Derrick Hurley]

Make sure you clear the counters on the interface too.  That will allow you to see if the CRC errors continue after your SFP swap.  If you continue to get CRC errors, then I would start swapping patch cables.

[mediaos718]

@ Derrick Yes, I clear the counters of both side.

@ Julio see config below

SW-1#sh run int po100

Building configuration...

Current configuration : 158 bytes

!

interface Port-channel100

no switchport

vrf forwarding TICKER

ip address x.x.x.x/x

end

SW-1#sh run int te1/5/13

Building configuration...

Current configuration : 172 bytes

!

interface TenGigabitEthernet1/5/13

no switchport

vrf forwarding TICKER

no ip address

channel-group 100 mode active

end

SW-1#sh run int te1/5/14

Building configuration...

Current configuration : 172 bytes

!

interface TenGigabitEthernet1/5/14

no switchport

vrf forwarding TICKER

no ip address

channel-group 100 mode active

end

SW-1#sh run int te2/5/13

Building configuration...

Current configuration : 172 bytes

!

interface TenGigabitEthernet2/5/13

no switchport

vrf forwarding TICKER

no ip address

channel-group 100 mode active

end

SW-1#sh run int te2/5/14

Building configuration...

Current configuration : 172 bytes

!

interface TenGigabitEthernet2/5/14

no switchport

vrf forwarding TICKER

no ip address

channel-group 100 mode active

end

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

SW-2#sh run int po100

Building configuration...

Current configuration : 130 bytes

!

interface Port-channel100

switchport access vlan 100

switchport mode access

end

SW-2#sh run int gig1/0/9

Building configuration...

Current configuration : 165 bytes

!

interface GigabitEthernet1/0/9

switchport access vlan 100

switchport mode access

channel-group 100 mode active

end

SW-2#sh run int gig2/0/9

Building configuration...

Current configuration : 165 bytes

!

interface GigabitEthernet2/0/9

switchport access vlan 100

switchport mode access

channel-group 100 mode active

end

SW-2#sh run int gig2/0/10

Building configuration...

Current configuration : 166 bytes

!

interface GigabitEthernet2/0/10

switchport access vlan 100

switchport mode access

channel-group 100 mode active

end

[Julio E. Moisa]

Hi

As I remember you cannot create an Etherchannel with L3 port on one switch and the other end as layer 2.  They should be L3 or L2 on both ends. 

Also you could remove the line vrf forwarding TICKER under the member interfaces, because it is managed by the Port channel interface. 

SW1

interface Port-channel100

no switchport

vrf forwarding TICKER

ip address x.x.x.x/x

end

SW2

interface Port-channel100

switchport access vlan 100

switchport mode access

end