MSTP guidelines and restrictions

Follow these restrictions and guidelines when configuring the MSTP:
  • Create VLANs before mapping them to the MSTP instances.
  • The Extreme implementation of the MSTP supports up to 32 MSTP instances and one MSTP region.
  • The MSTP force-version option is not supported.
  • You must create VLANs before mapping them to the MSTP instances.
  • For two or more switches to be in the same the MSTP region, they must have the same VLAN-to-instance map, the same configuration revision number, and the same region name.
  • MSTP is backward compatible with the STP and the RSTP.
  • Only one MSTP region can be configured on a bridge.
  • A maximum of 4090 VLANs can be configured across the 32 MSTP instances.
  • MSTP and topology groups cannot be configured together.
  • MSTP configured over MCT VLANs is not supported.

Default MSTP configuration

As well as the defaults listed in the section Understanding the default STP configuration, there are defaults that apply only to MSTP configurations.

Parameter

Default setting

Cisco interoperability

Disabled

Device priority (when mapping a VLAN to an MSTP instance)

32768

Maximum hops

20 hops

Revision number

0

9036690-01 Rev AB