Link Aggregation between stacked N4032's and stacked 6442's

Question

Up until last evening, I had a (4) port LAG between 2xN4032s & 2x6224's each in an indpendant stack configuration. These switches are being used as a path from our VMWARE system to our corporate LAN and up until a reset of the N4032's last evening, the configuration was working well, atleast I thought.

I am leaning towards this being a Spanning Tree issue on the channel being utilized. When doing a show interface port-channel, the port-channel had been in a discarding state since last evenings reload of the stack. I'm looking for recommendations as to how I would go about ensuring the 4 ports being utilized in the path are configured correctly. As of this writing, i've backed out the LAG simply relying on a single port configured to pass the LAN VLAN traffic and it is working.

I had ports unit1 - 1/2 & unit2 - 1/2 of the N4032 connected to unit 1-5/6 & unit2 - 5/6 respectively. I had the port-channel mode in GENERAL adding the VLAN as a tagged member. I had portfast enabled as well as RSTP enabled. Any information as to how this should look between the 4 ports would be greatly appreciated.

The overall VM-LAN traffic path is as follows; HOST1 > STACKED-N4032 <(4PORT-LAG)> STACKED-6224 <(2PORT-LAG)> 6224 EDGE > Corporate LAN

jimbennin · Answer

Maybe I'm overthinking this a bit, but maybe my cross-links between switches is the issue in causing a switching loop?

DELL-Josh Cr · Answer

Hi,

With all of the crossing and loops you are creating, STP is going to discard some ports. The LAG should not affect spanning tree for what is forwarded or discarded. Spanning-tree seeing a loop will, and on a reboot interfaces may initialize in a different order.

jimbennin · Answer

As of now,  I've removed the 4 member LAG and have just one port configured between the 2 stacks until I figure out an optimal config.

jimbennin · Answer

I suspect I need to get my Layer 2 network house in order before going too much further.

jimbennin · Answer

Ok - I've come to the conclusion that I'm just not getting the configuration of the PORT-CHANNELs correctly. Does anyone have any guides or suggestions as to how we should go about connecting (4) ports from each switch as a LAG creating a 4GB pipe between and only carrying VLAN ID 100 as a tagged member. I will post my last attempted config shortly.

I can now see where 3 of the 4 ports are in a blocking state as they should be without membership to a LAG.

Networking General

Link Aggregation between stacked N4032's and stacked 6442's

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