Multiple Spanning Tree Protocol (MSTP) Properties Configuration on ESW2-350G Switches

Objective

Multiple Spanning Tree Protocol (MSTP) is an extension to Rapid Spanning Tree Protocol (RSTP). MSTP further develops the usefulness of VLANs. MSTP configures a separate spanning tree for each VLAN group and blocks all but one possible alternate path within each spanning tree. MSTP allows formation of MST regions that can run multiple MST instances (MSTI). Multiple regions and other STP bridges are interconnected using one single common spanning tree (CST). Several VLANs can be mapped to a single spanning tree instance, how to determine which VLAN is to be associated with which instance. Region plays a vital role to determine the VLAN to a STP instance. MST must be able to interact with 802.1q-based networks, because 802.1q is another IEEE standard. For 802.1q, a bridged network only implements a single spanning tree (CST). The IST instance is simply an RSTP instance that extends the CST inside the MST region.

The objective of this article is to explain how to configure the properties of the MSTP for ESW2-350G switches.

Applicable Devices

• ESW2-350G
• ESW2-350G-DC

Software Version

• 1.3.0.62

Configuration of the MSTP Properties

Step 1. Log in to the web configuration utility and choose Spanning Tree > MSTP Properties. The Properties page opens:

Step 2. Enter a user defined spanning tree protocol name in the Region Name field. In the above image the Region Name field given is a MAC address of a port with MSTP running.

Step 3. Enter a revision number from 0 to 65535 into the Revision field. Revision number identifies the current MST configuration.

Step 4. Enter a number from 1 to 40 into the Max Hops field to set how many hops happen in a region before the bridge protocol data unit packet is discarded. The default is 20.

Note: The IST Active displays what the region Active switch is. If you are unfamiliar with the terms used, check out Cisco Business: Glossary of New Terms.

Step 5. Click Apply.

Caution: This only saves your configuration to the running configuration file. This means any changes made will be lost if the device is rebooted. If you wish to save these changes even after a system reboot, you need to copy the running configuration file to the startup configuration file refer to Copy or Save Configuration on ESW2-350G Switch.