vStpMstRegionConfigDigest 1.3.6.1.4.1.6486.800.1.2.1.12.1.1.1.6.1.3

The Mst Region identifier, a 16 octet field of type HMAC-MD5. It is an encoding of the VID to MSTID table and sent in the MSTP BPDU to allow bridges to recognize their neighbors region.