Dell Networking N4000 Series Configuration Manual page 938

The administrator should also ensure that the following are identical
before enabling MLAG:
– FDB entry aging timers
– Static MAC entries.
– ACL configuration
4 Interface Configuration
– PFC configuration
– CoS queue assignments
5 VLAN configuration
– MLAG VLANs must span the MLAG topology and be configured on
both MLAG peers. This means that every MLAG VLAN must connect
to two partner LAGs.
– VLAN termination of an MLAG VLAN on an MLAG peer is not
supported.
6 Switch firmware versions
Except during firmware upgrade, the peer switch firmware versions must
be identical, as subtle differences between versions may cause instability.
The administrator must ensure that the above configuration items are
configured identically on the MLAG interfaces on both of the MLAG peers
before enabling the MLAG feature. If the configuration settings are not in
sync, the MLAG behavior is undefined. Once the above configuration is in
place and consistent, the two switches will form an MLAG that operates in
the desired manner. The MLAG may form even if the configuration is not
consistent, however, it may not operate consistently in all situations.
938
Configuring Link Aggregation