1-30By then, you can perform an mCheck operation to force the port to migrate to the MSTP (or RSTP)mode.You can perform mCheck on a port through the following two approaches, which lead to the sameresult.Performing mCheck globallyFollow these steps to perform global mCheck:To do... Use the command... RemarksEnter system view system-view —Perform mCheck stp mcheck RequiredPerforming mCheck in interface viewFollow these steps to perform mCheck in interface view:To do... Use the command... RemarksEnter system view system-view —Enter Ethernet interface view, or Layer2 aggregate interface viewinterface interface-typeinterface-number —Perform mCheck stp mcheck RequiredAn mCheck operation takes effect on a device only when MSTP operates in RSTP or MSTP mode.Configuring Digest SnoopingAs defined in IEEE 802.1s, interconnected devices are in the same region only when the MSTregion-related configurations (domain name, revision level, VLAN-to-instance mappings) on them areidentical. An MSTP-enabled device identifies devices in the same MST region by checking theconfiguration ID in BPDU packets. The configuration ID includes the region name, revision level,configuration digest that is in 16-byte length and is the result calculated via the HMAC-MD5 algorithmbased on VLAN-to-instance mappings.Since MSTP implementations vary with vendors, the configuration digests calculated using private keysis different; hence different vendors’ devices in the same MST region can not communicate with eachother.Enabling the Digest Snooping feature on the port connecting the local device to a third-party device inthe same MST region can make the two devices communicate with each other.
