Multicast Address - TRENDnet TI-PG1284i User Manual

TRENDnet User's Guide

Multicast Address

A multicast address is associated with a group of interested receivers. According to RFC
3171, addresses 224.0.0.0 to 239.255.255.255, the former Class D addresses, are
designated as multicast addresses in IPv4.
The IANA owns the OUI MAC address 01:00:5e, therefore multicast packets are delivered
by using the Ethernet MAC address range 01:00:5e:00:00:00 - 01:00:5e:7f:ff:ff. This is 23
bits of available address space.
The first octet (01) includes the broadcast/multicast bit. The lower 23 bits of the 28-bit
multicast IP address are mapped into the 23 bits of available Ethernet address space. This
means that there is ambiguity in delivering packets. If two hosts on the same subnet each
subscribe to a different multicast group whose address differs only in the first 5 bits,
Ethernet packets for both multicast groups will be delivered to both hosts, requiring the
network software in the hosts to discard the unrequired packets.
Class Address Range
Class A 1.0.0.1 to 126.255.255.254
Class B 128.1.0.1 to 191.255.255.254
Class C 192.0.1.1 to 223.255.254.254
Class D 224.0.0.0 to 239.255.255.255
Class E 240.0.0.0 to 254.255.255.254
© Copyright 2016 TRENDnet. All Rights Reserved.
Supports
Supports 16 million hosts on each of 127
networks.
Supports 65,000 hosts on each of 16,000
networks.
Supports 254 hosts on each of 2 million
networks.
Reserved for multicast groups.
Reserved for future use, or Research and
Development Purposes.
IP multicast
Description
address
224.0.0.0 Base address (reserved)
The All Hosts multicast group that contains all systems on the same
224.0.0.1
network segment
The All Routers multicast group that contains all routers on the same
224.0.0.2
network segment
The Open Shortest Path First (OSPF) AllSPFRouters address. Used to
224.0.0.5
send Hello packets to all OSPF routers on a network segment
The OSPF AllDRouters address. Used to send OSPF routing information
224.0.0.6
to OSPF designated routers on a network segment
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