LACP between N-series and S4128F (VLT) core

Hello @Plati1337,

Good to see you back in the Dell Community!

Sadly, we cannot help directly in configurations as there are some Dell Professional services that can handle this task on your behalf. In case you need this professional help, please let us know and I will make sure to show you how you can contact them. But, of course, we can try to offer you some help:

I can confirm you that it is possible to configure a LACP between two S4128F (VLT) and access switches (N-series 1100/2000).

What OS are you using? 10 or 9? Spamming tree is active? I ask this, because if you have both sides active you should have loops. So that would be something to consider. 

If you are using OS10. Please, reference the material on page 174: https://dell.to/361Vt8O and this article: https://dell.to/2SFwViJ

And if you are using OS9, check this: https://dell.to/364ONqj

Finally, if your switch is still in warranty you can contact phone or online support and send them the switch logs. They will not perform the configuration but they will be able to tell you if something is incorrect.

Regards.

Thanks for your replies. 
I have now tried configure N2000 stack for the access switches, but it is still the same. 
I do, however see this entry in the log: 
DOT3AD[dot3ad_core_lac]: dot3ad_lacp.c(2339) 11030 %% WARN Interface Te2/0/1 partner priority 4096 is not same as existing members of LAG interface Po1 (4096). Not adding interface Te2/0/1 as active member of LAG interface Po1.

But I have configures the same priority on each of the interfaces, on both sides. I will attach the configuration here, I hope you will locate what I am doing wrong. 

Core S4128F running OS10, configured in VLT: 

Core-1:
# show vlt 1
Domain ID : 1
Unit ID : 2
Role : primary
Version : 2.3
Local System MAC address : cc:48:3a:fa:32:76
Role priority : 4096
VLT MAC address : 00:00:00:00:00:02
IP address : fda5:74c8:b79e:1::2
Delay-Restore timer : 90 seconds
Peer-Routing : Disabled
Peer-Routing-Timeout timer : 0 seconds
VLTi Link Status
port-channel1000 : up

VLT Peer Unit ID System MAC Address Status IP Address Version
----------------------------------------------------------------------------------
1 cc:48:3a:fa:36:f6 up fda5:74c8:b79e:1::1 2.3

interface port-channel2
no shutdown
switchport mode trunk
switchport access vlan 1
switchport trunk allowed vlan 10-11,20
vlt-port-channel 2

interface ethernet1/1/12
no shutdown
channel-group 2 mode active
no switchport
flowcontrol receive on
lacp port-priority 4096
lacp rate fast

Core-2:
# show vlt 1
Domain ID : 1
Unit ID : 1
Role : secondary
Version : 2.3
Local System MAC address : cc:48:3a:fa:36:f6
Role priority : 8192
VLT MAC address : cc:48:3a:fa:32:76
IP address : fda5:74c8:b79e:1::1
Delay-Restore timer : 90 seconds
Peer-Routing : Disabled
Peer-Routing-Timeout timer : 0 seconds
VLTi Link Status
port-channel1000 : up

VLT Peer Unit ID System MAC Address Status IP Address Version
----------------------------------------------------------------------------------
2 cc:48:3a:fa:32:76 up fda5:74c8:b79e:1::2 2.3

interface port-channel2
no shutdown
switchport mode trunk
switchport access vlan 1
switchport trunk allowed vlan 10-11,20
vlt-port-channel 2

interface ethernet1/1/12
no shutdown
channel-group 2 mode active
no switchport
flowcontrol receive on
lacp port-priority 4096
lacp rate fast

N2000 stack: 

interface port-channel 1
switchport mode trunk
switchport trunk allowed vlan 10-11,20

interface Te1/0/1
channel-group 1 mode active
lacp port-priority 4096
switchport mode trunk
switchport trunk allowed vlan 10-11,20

interface Te2/0/1
channel-group 1 mode active
lacp port-priority 4096
switchport mode trunk
switchport trunk allowed vlan 10-11,20

#show interfaces port-channel 1

Channel Ports Ch-Type Hash Type Min-links Local Prf Rx Util Tx Util
------- ----------------------------- -------- --------- --------- --------- --------- ---------
Po1 Active: Te1/0/1 Dynamic 7 1 Disabled 0 0
Inactive: Te2/0/1

I would try removing lacp port-priority and lacp rate on the physical interfaces unless there is a particular need. 

Generally port priority is used to decide which ports should be put into standby mode when there is a hardware limitation that prevents all compatible ports from aggregating. 

I can also see that flow control is enabled on the S4128F physical interfaces participating in the port-channel but not on the N2000 stack interfaces. I would also try turning this off and testing. 

After making these changes I would perform a shutdown then no shutdown of of the port-channel interface.