MSTP Instance to VLAN Configuration on SFE/SGE Managed Switches

Objective

Multiple Spanning Tree Protocol (MSTP) is an extension of RSTP that helps VLANs become more efficient and useful. MSTP configures a different Spanning Tree for each VLAN. Only one path on a Spanning Tree is left open for transmission while the rest of the paths are blocked. In this way, the number of STP instances can be kept to a minimum, which saves resources on the switch and helps the switch to run more smoothly and not get bogged down. The user can map each STP instance (logical topology for the connected devices) to a VLAN. This article explains how to map MSTP instances to VLANs and configure instance settings on the SFE/SGE Managed Switches.

Applicable Devices

• SFE/SGE Managed Switches

MSTP Configuration

Map MSTP Instance to VLAN

Step 1. Log in to the web configuration utility on the switch and choose Bridging > Spanning Tree > MSTP > Instance to VLAN. The Instance to VLAN page opens:

Step 2. Enter the number of the MSTP instance that you would like to map to the VLAN in the Instance ID field that corresponds to the desired VLAN.

Step 3. (Optional) Scroll down and click Next if the desired VLAN is not on the current page.

Step 4. Click Apply.

Instance Settings

Step 1. Use the web configuration utility on the switch to choose Bridging > Spanning Tree > MSTP > Instance Settings. The Instance Settings page opens:

Step 2. Choose the ID number of the MSTP instance that you would like to configure from the Instance ID drop-down list. A list of the VLANs that are mapped to the chosen instance are displayed in the Include VLAN list.

Step 3. Enter the desired priority of the instance on the device in the Bridge Priority field. The device with the lowest priority is the root bridge. The range is from 0 to 61440. The value must be a multiple of 4096.

The following fields are displayed:

• Designated Root Bridge ID — The priority of the root bridge and the MAC address of the root bridge. The root bridge has the lowest path cost to the instance ID.

• Root Port — The root port of the chosen instance.

• Root Path Cost — The root port path cost of the chosen instance.

• Bridge ID — The priority and MAC address of the chosen instance.

• Remaining Hops — The number of hops that remain before the traffic reaches the next destination.

Step 4. Click Apply to save your settings.