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EES4710BD 10 Slots L2/L3/L4 Chassis Switch
group at any time.
A multicast group can be either a perpetual one or temporary one. Part of multicast addresses are
assigned officially and referred to as the perpetual multicast group. The IP address of a perpetual
multicast group remains the same, but the membership can be changed. A perpetual multicast group
can have any number of members, even zero. IP multicast addresses not reserved for perpetual
multicast group can be used by temporary multicast groups.
224.0.0.0 – 224.0.0.255 are reserved multicast addresses (perpetual group address), the address
224.0.0.0 is not used, the other addresses are available for routing protocols; 224.0.1.0 –
238.255.255.255 are multicast addresses available to users (temporary group address), and is valid
for the whole network; 239.0.0.0 – 239.255.255.255 are local administrative multicast address and is
valid for specific local ranges. The following is a list for common reserved multicast addresses:
224.0.0.0 Base address (reserved)
224.0.0.1 All-host address
224.0.0.2 All-multicast-router address
224.0.0.3 Not for allocation
224.0.0.4 DVMRP router
224.0.0.5 OSPF router
224.0.0.6 OSPF DR
224.0.0.7 ST router
224.0.0.7 ST host
224.0.0.9 RIP-II router
224.0.0.10 IGRP router
224.0.0.11 Active proxy
224.0.0.12 DHCP Server/Relay proxy
224.0.0.13 All PIM routers
224.0.0.14 RSVP packaging
224.0.0.15 All CBT routers
224.0.0.16 Specified SBM
224.0.0.17 All SBMS
224.0.0.18 VRRP
When transferring unicast IP packets on Ethernet, the destination MAC address is the MAC of the
receiver. However, in transferring multicast packets, as the destination is no longer one specific
recipient but a group with unknown members, the destination address used is the multicast MAC
address. Multicast MAC address is corresponding 5 to the multicast IP address. According to IANA
(Internet Assigned Number Authority), the 24 MSbs of multicast MAC is 0x01005e and 23 LSbs of
multicast MAC is the same of the multicast IP address.
As only 23 bits out of the 28 LSbs of multicast IP address are mapped to MAC address, for one
MAC address there will be 32 corresponding multicast IP addresses.
In the multicast model, the source host sends information to the host group represented by the