It's important to note that PVST/PVST+ is Cisco proprietary.
They do support one instance of STP per VLAN, and it is enabled by default. You can enable/disable STP on the following levels (taken from the NetIron config docs):
- Globally - Affects all VLANs
- Individual VLAN - Affects all ports within the specified VLAN. When you enable or disable STP within a VLAN, the setting overrides the global setting. Thus, you can enable STP for the ports within a VLAN even when STP is globally disabled, or disable the ports within a port-based VLAN when STP is globally enabled.
- Individual Port - Affects only the individual port. However, if you change the STP state of the primary port in a LAG group, the change affects all ports in the LAG group.
Depending on your code rev, you can enter config mode for the VLAN and either do:
[no] spanning-tree 802-1w (used on older versions of code)
I know that newer NetIron gear has PVST/PVST+ compatibility modes which you can turn on at the interface level with:
But this also implies that you're going to be running MST, which you said you're not going to do.