Problem with LACP.

[sn00p]

Hi.
I have some problem making LACP work correctly.
I want to connect 3850 (2 switches stack) with 2960X (3 switches stack) with 2 SFP-10G-ACTIVE-CABLE's.

My configuration:

3850:

* interface TenGigabitEthernet1/1/1
description --TO-2960X--
switchport mode trunk
channel-protocol lacp
channel-group 10 mode active

* interface TenGigabitEthernet2/1/1
description --TO-2960X--
switchport mode trunk
channel-protocol lacp
channel-group 10 mode active

*interface Port-channel10
description --TO-2960X--
switchport mode trunk

Te1/1/1 --TO-2960X-- connected trunk full 10G SFP-10G-ACTIVE-CABLE
Te2/1/1 --TO-2960X-- suspended trunk full 10G SFP-10G-ACTIVE-CABLE
Po10 --TO-2960X-- connected trunk a-full a-10G

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
10 Po10(SU) LACP Te1/1/1(P) Te2/1/1(s)

2960X:

* interface TenGigabitEthernet1/0/1
description --FROM-3850--
switchport mode trunk
channel-protocol lacp
channel-group 10 mode active

* interface TenGigabitEthernet2/0/1
description --FROM-3850--
switchport mode trunk
channel-protocol lacp
channel-group 10 mode active

* interface Port-channel10
description --FROM-3850--
switchport mode trunk

Te1/0/1 --FROM-3850-- connected trunk full 10G SFP-10GBase-ACUxM
Te2/0/1 --FROM-3850-- suspended trunk full 10G SFP-10GBase-ACUxM
Po10 --FROM-3850-- connected trunk a-full 10G

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
10 Po10(SU) LACP Te1/0/1(P) Te2/0/1(s)

As You can see one of the link gets suspended with info:
3850: *Apr 10 19:02:45.997: %EC-5-L3DONTBNDL2: Te2/1/1 suspended: LACP currently not enabled on the remote port.
2960X: *Apr 10 20:39:45: %EC-5-L3DONTBNDL2: Te2/0/1 suspended: LACP currently not enabled on the remote port.

3850 is my core switch, i have 5 more LACP configured same as above, and they're working just fine.
Do You have any ideas?

[Reza Sharifi]

Hi,

So, Te2/1/1 connects directly to Te2/0/1? Could be an SFP+ issue maybe. Does the same cable work in the other port? Have you tried a different cable? what is the distance between the stacks?

HTH

[sn00p]

Hi Reza, thanks for reply,

Correct - Te1/1/1 connects to Te1/0/1 and Te2/1/1 connects to Te2/0/1.

Yes, I've tried different SFP-10G-ACTIVE-CABLE cable - no effect. Unfortunately there are no free 10G ports for tests.
Stack's are near, about 2-3 meters apart.

Yesterday I've noticed something strange with this 3850.
I was trying to connect CISCO 2504 WLC.

When connected to first 2 sections (ports Gi2/0/1-24) interface was going up, but there was INCOMPLETE inscription in ARP....

Connecting to other port in other section on that switch resolved the issue... Of course WLC and port configuration wasn't changed at all.

I'm starting to think that there is some IOS or even hardware fault on that switch.

At the moment 3850 stack is running on IOS-XE 03.07.05E, I'm thinking on upgrade toI Fuji-16.9.5.

Any thoughts?

[Reza Sharifi]

Hi,

I recommend opening TAC case for this. I have seen something similar with 3850 stack connecting to 6700 (VSS) and if I remember correctly, the only thing fixed it was an IOS upgrade.

HTH

[Reza Sharifi]

Hi,

And one more thing if you could test. Does it make a difference if you use mode "on" instead of LACP.  Try to understand if this is a LACP protocol related issue/bug.

HTH

[sn00p]

Hi.

Of course I've tested a few different sets lika active-active, active-passive and "on" - still no results.

I think that I will upgrade IOS to mentioned earlier Fuji-16.9.5 after holiday break, and if that won't solve the issue, will open support case as You adviced.

The one I'm really concerned about is connectivity on two first sections (mentioned earlier), hope IOS upgrade will do the job.

Thanks for help anyway.

[sn00p]

FYI
It was a switch issue.
After replacing faulty unit, LACP went up correctly, no further configuration required.
RMA rocks ;)
Thanks for help anyway.

Regards.