Connected: An Internet Encyclopedia
6.4. Extensions to an Ethernet Local Network Module

Up: Connected: An Internet Encyclopedia
Up: Requests For Comments
Up: RFC 1112
Up: 6. SENDING MULTICAST IP DATAGRAMS
Prev: 6.3. Extensions to the Local Network Service Interface
Next: 6.5. Extensions to Local Network Modules other than Ethernet

6.4. Extensions to an Ethernet Local Network Module

6.4. Extensions to an Ethernet Local Network Module

The Ethernet directly supports the sending of local multicast packets by allowing multicast addresses in the destination field of Ethernet packets. All that is needed to support the sending of multicast IP datagrams is a procedure for mapping IP host group addresses to Ethernet multicast addresses.

An IP host group address is mapped to an Ethernet multicast address by placing the low-order 23-bits of the IP address into the low-order 23 bits of the Ethernet multicast address 01-00-5E-00-00-00 (hex). Because there are 28 significant bits in an IP host group address, more than one host group address may map to the same Ethernet multicast address.


Next: 6.5. Extensions to Local Network Modules other than Ethernet

Connected: An Internet Encyclopedia
6.4. Extensions to an Ethernet Local Network Module