Issues with LAG across N4032 Switch Stack

Question

I have had issues with stacking 2 N4032's.  First issue was the slave switch would disconnect and stop responding after 8 hours or so.  I applied firmware version 6.3.1.13 which appears to have solved that issue. My current issue is that is that I have a LAG (LACP)  that has port on each switch in the stack and I have intermittent communication issues. I can ping a client through the LAG and some times it responds some times it doesn't.   Both ports show as active when running 'show interface Port -Channel 11' .  The FortiGate it is connecting too is also shows both ports active and connected.  The only thing I noticed is that the FortiGate shows its LACP speed as fast and the remote connection as LACP speed as slow, Here is the config: interface Te1/1/1channel-group 11 mode activeexit interface Te2/1/1channel-group 11 mode activeexit interface port-channel 11switchport mode trunkswitchport trunk allowed vlan add 10,15,20,30,39,50exit Here is the weird part, if I move the port so it is on the same switch everything works fine.   I have tried disabling STP on the port-channel and the individual ports with no success. Any ideas?  Bad Switch?  Bad Firmware? Bad User?

DELL-Josh Cr · Answer

Hi, Are you able to try different ports on each switch and see if that works? Is it just ping that stops working or all communications drop? What do you have to do to get it to work again?

BigJesseD · Answer

The only way to fix the issue is to disable the port coming from the slave switch. Traffic will function normally after that. If I disable the master port all traffic stops even though the Port Channel show Active.

Could this be a stacking issue? Currently I have ports te1/0/21-24 and te2/0/21-24 set as stacking ports. I have done no other stacking configuration.

unnikpr · Answer

Is this still open? I am faceing same iasue.

bealdrid2 · Answer

I had issues with the N4032 in a stacked configuration with port channels. Our problem ended up being the hashing mode set on the switch. The default is mode "7" which is "Enhanced". This did resulted in intermittent drops, etc similar to what you're seeing. Workaround for us was to use mode "3", Src IP/port. Hope it helps.

interface port-channel 1
hashing-mode 3

https://www.dell.com/community/Networking-General/N2000-arp-issues-with-Enhanced-hashing-mode/td-p/5055459

https://www.dell.com/support/article/us/en/19/how10364/how-to-create-link-aggregation-groups-lags-on-dell-networking-powerconnect-switches?lang=en

Networking General

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