About MST
Multiple Spanning Tree (MST) is the IEEE 802.1s standard that allows two or more VLANs to be assigned to a spanning tree instance. Each instance has a spanning tree topology independent of other spanning tree instances. This architecture provides multiple forwarding paths for data traffic, enables load balancing, and reduces the number of Spanning Tree Protocol (STP) instances required to support a large number of VLANs. MST improves the fault tolerance of the network because a failure in one instance (forwarding path) does not affect other instances (forwarding paths). MST instances with the same name, revision number, and VLAN-to-instance mapping combine to form an MST region. The MST region appears as a single bridge to spanning tree configurations outside the region. MST fails over to IEEE 802.1D STP when it receives an 802.1D message from a neighboring switch.
Note |
Spanning tree is used to refer to IEEE 802.1w and IEEE 802.1s. If the text is discussing the IEEE 802.1D Spanning Tree Protocol, 802.1D is stated specifically. |
In Cisco UCS Director, MST configuration is supported on the following Cisco network devices:
- Cisco Nexus 3000 Series switches
- Cisco Nexus 5000, 5500, and 5672 Series switches
- Cisco Nexus 6000 Series switches
- Cisco Nexus 7000 Series switches
- Cisco Nexus 9000 Series switches