MME principles ************** Description =========== The format of Management Messages is based on the standard Ethernet frame format, with a unique Ethertype assigned to HomePlug. HomePlug AV has a different Ethertype assignment than the Ethertype assigned to HomePlug 1.0.1. Management Messages are used for station- to-station control communication, but also may be used for control messages to and from a Higher Layer Entity (HLE). The Ethernet format enables messages to HLEs across an Ethernet network. Format ====== .. list-table:: MME format :widths: 7 6 6 60 :header-rows: 1 * - Field - Octet number - Field size (bits) - Definition * - ODA - 0 \- 5 - 48 - Original Destination Address * - OSA - 6 \- 11 - 48 - Original Source Address * - VLAN Tag - 12 \- 15 - 32 - IEEE 802.1Q VLAN Tag (optional) * - MTYPE - 16 \- 17 - 16 - 0x88e1 (IEEE\-assigned Ethertype) Note: 0x88 is transmitted in the least\-significant octet and 0xe1 is transmitted in the most\-significant octet in conformance with IEEE 802.3. * - MMV - 18 - 8 - Management Message Version * - MMTYPE - 19 \- 20 - 16 - Management Message Type * - FMI - 21 - 4 - Fragmentation Management Information – 4 MSBs are Number of Fragments (NF_MI) of the MMENTRY 0x00 = MMENTRY is not Fragmented 0x01 = MMENTRY is Fragmented into two parts 0x02 = MMENTRY is Fragmented into three parts ... * - - - 4 - 4 LSBs are Fragment Number (FN_MI) of the MMENTRY 0x00 = First or Only Fragment 0x01 = Second Fragment ... * - - 22 - 8 - Fragmentation Message Sequence Number (FMSN) * - MMENTRY - 23 \- 25 - 24 - SPiDCOM OUI (0x00\-0x13\-0xd7) or Transaction ID * - - 26 \- ... - \- - Management Message Entry Data * - MME PAD - \- - 0 \- 46 - MME PAD **Warning:** HomePlug AV messages do not contain a SPiDCOM OUI or transaction ID field. Message body directly starts at MMENTRY index. Vendor Specific and Manufacturing Specific messages contain a SPiDCOM OUI field at index 23 – 25. This OUI is 0x00-0x13-0xd7. Driver messages contain a Transaction ID field at index 23 - 25. This transaction ID field is used to allow multiplexing of several messages with the same MTYPE.