[c-nsp] Nexus 9k reserved vlans and MST

[Wayne Lee]

Hello

We have several Nexus 9K's which we have changed the system reserved
vlans from the defaut to 3600-3727. We now have a requirement to
migrate to MST.

The Cisco docs state “You cannot map VLANs 3968 to 4095 to an MST
instance. These VLANs are reserved for internal use by the device.”

The doc does not mention if those vlans can be used for MST if they
are no longer reserved. As a test I created the the below MST config
but not enabled MST yet,


spanning-tree mst configuration
name TEST-MST
revision 1
instance 1 vlan 2-3599
instance 2 vlan 3729-4092
exit
end

I didn't see any errors but as MST is not actually enabled yet I'm not
convinced so I tried the below by adding in vlan 3601 which is part of
the currently reserved vlans.

spanning-tree mst configuration
name TEST-MST
revision 1
instance 1 vlan 2-3599
instance 2 vlan 3729-4092
instance 3 vlan 3601
exit
end

Again I don't see any errors when I expected to by using a known reserved vlan.

Has anybody changed the system reserved vlans and enabled vlans 3968
and above in MST ?

The current RSTP setup is working well with the reserved vlans but the
rack switches are reaching the RSTP limit (128)

Thanks