HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 2 - LAN Switching Co - Page 87

To enable the spanning tree feature: Step 1. Enter system view. Command system-view 2. Enable the spanning tree feature globally. stp enable 3. Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface interface-type interface-number interface view. 4. Enable the spanning tree feature for the port. stp enable Remarks N/A By default, the spanning tree feature is disabled globally. N/A Optional. By default, the spanning tree feature is enabled for all ports. Performing mCheck If a port on a device that is running MSTP or RSTP connects to an STP device, this port automatically transitions to the STP mode. However, it cannot automatically transition back to the original mode under the following circumstances: • The STP device is shut down or removed. • The STP device transitions to the MSTP or RSTP mode. Suppose Device A running STP, Device B with no spanning tree feature enabled, and Device C running RSTP or MSTP are connected in order. Device B will transparently transmit the STP BPDUs, and the port on Device C and connecting to Device B will transition to the STP mode. After you enable the spanning tree feature on Device B, to run RSTP or MSTP between Device B and Device C, you must perform an mCheck operation on the ports interconnecting Device B and Device C, in addition to configuring the spanning tree to operate in RSTP or MSTP mode on Device B. To forcibly transition the port to operate in the original mode, you can perform an mCheck operation. The following methods for performing mCheck produce the same result. Performing mCheck globally Step 1. Enter system view. 2. Perform mCheck. Command system-view stp mcheck Performing mCheck in interface view Step 1. Enter system view. 2. Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view. 3. Perform mCheck. 78 Command system-view interface interface-type interface-number stp mcheck