Ethernet
Ethernet frames with a value of 1 in the least-significant bit of the first octet of the destination address are treated as multicast frames and are flooded to all points on the network. While frames with ones in all bits of the destination address (FF:FF:FF:FF:FF:FF) are sometimes referred to as broadcasts, Ethernet network equipment generally does not distinguish between multicast and broadcast frames. Modern Ethernet controllers filter received packets to reduce CPU load, by looking up the hash of a multicast destination address in a table, initialized by software, which controls whether a multicast packet is dropped or fully received.
| Ethernet multicast address | Type Field | Usage |
|---|---|---|
| 01-00-0C-CC-CC-CC | 0x0802 | CDP (Cisco Discovery Protocol), VTP (VLAN Trunking Protocol) |
| 01-00-0C-CC-CC-CD | 0x0802 | Cisco Shared Spanning Tree Protocol Address |
| 01-80-C2-00-00-00 | 0x0802 | Spanning Tree Protocol (for bridges) IEEE 802.1D |
| 01-80-C2-00-00-08 | 0x0802 | Spanning Tree Protocol (for provider bridges) IEEE 802.1AD |
| 01-80-C2-00-00-02 | 0x8809 | Ethernet OAM Protocol IEEE 802.3ah (A.K.A. "slow protocols") |
| 01-00-5E-xx-xx-xx | 0x0800 | IPv4 Multicast (RFC 1112) |
| 33-33-xx-xx-xx-xx | 0x86DD | IPv6 Multicast (RFC 2464) |
Read more about this topic: Multicast Address