Configuring Link Aggregation 955
Shutting down a MLAG port-channel on the secondary MLAG peer has no
effect. The operator can shut down the individual links instead.
The spanning tree status is only shown correctly on the primary MLAG
peer.
The secondary switch shows the spanning tree status as root. This is
because there are no ports belonging to spanning tree on the secondary
switch. MLAG ports on the secondary switch belong to the spanning tree
running on the primary switch.
On a failover from the primary MLAG peer to the secondary MLAG peer,
the ports are made members of the secondary MLAG peer switch's
spanning tree and spanning tree reconvergence occurs. The forwarding
database and ARP cache are flushed and relearned.
MLAG (VPC) status only shows correctly on the primary MLAG peer and
does not show correctly on the secondary MLAG peer. Status is not
forwarded from the primary MLAG peer to the secondary MLAG peer.
The Dell Networking MLAG solution is not peer-compatible with other
vendor's multichassis LAG solutions. Dell Networking switches configured for
MLAG cannot peer with another vendor switch.
IGMP snooping is not supported on MLAG-enabled switches. Disable IGMP
snooping before enabling MLAG.
MLAG interfaces and non-redundant ports cannot be members of the same
VLAN; i.e., a VLAN may contain MLAG interfaces or a VLAN may contain
non-redundant ports, but not both.
The Dell Networking MLAG solution supports MSTP and RSTP spanning
tree modes only. Spanning tree may also be disabled on the MLAG peers.
STP-PV and RSTP-PV are not supported in the MLAG solution.
Only two switches are supported as MLAG peers. These switches may not be
stacked with other switches.
The MLAG peer switches synchronize the state of spanning tree, the L2
forwarding cache, and other protocols to support reduced convergence times
during MLAG link and MLAG swi tch failures. The synchronized state is only
available on the MLAG primary switch. Table28-1 indicates which switch
features synchronize their state across the MLAG peers.