OID_WAN_PROTOCOL_TYPE
The OID_WAN_PROTOCOL_TYPE OID informs the underlying driver of a bound protocol's type, as a single-byte network-level protocol identifier (NLPID).
Alternatively, a protocol can specify a 6-byte Sub-Network Access Protocol (SNAP) NLPID, with 0x80-0x00-0x00-0x00 for the first four bytes and an Ethertype for the last two bytes.