Multicast IP Addresses notation

As explained in the chapter 1, IANA has reserved Class D range for multicast. The difference between the multicast and unicast address, is that unicast IP addresses represent a single network device while multicast represent a group of network devices or receivers.

The range of IP that is reserved for multicast is from until But how did we come with this range. For this, we need to look at the binary representation of the IP address:

As you can see, the first 4 bits from the first octet are 1110 in binary which means that we have multicast addresses from until

However, it is important to mention that you cannot use all this range when you want to do multicast in your network. There are some ranges that are reserved such as the range – which is reserved by IANA. This range is used with network protocols. If you use this range for multicast, then it will not be forwarded by routers between subnets. Here below a list of reserved multicast addresses (you may have seen some of them before):

Address Usage All Hosts All Multicast Routers Unassigned DVMRP Routers OSPF Routers OSPF DR/BDR Router ST Routers ST Hosts RIPv2 Routers EIGRP Routers Mobile Agents DHCP Server / Relay All PIM Routers RSVP Encapsulation All CBT Routers Designated SBM All SBMS VRRP – 255 Unassigned

As you can see, the whole range is reserved by IANA and you may have recognized some of the multicast addresses such as & 224.0.06 which are used for OSPF, which is used in RIPv2 and so forth. So bottom line, do not use the range of when you want to use multicast in your network.

Additionally, IANA also reserved the subnet of to be used for certain applications. If you use this range, the router can route it unlike range, however it is highly recommended to not use it because this is used for some applications such as:

Address Usage VMTP Managers Group NTP SGI-Dogfight Rwhod NSS SUN NIS+ Any Private Experiment DVMRP on MOSPF Mtrace RSVP-encap-1 RSVP-encap-2 Cisco-RP-Announce Cisco-RP-Discovery Mbone-VCR-Directory Tibco Multicast 1 Tibco Multicast 2 – Unassigned

In summary, when you want to do multicast do not use the following 2 ranges:

  • 0.0.0/24
  • 0.1.0/24

The last thing that I want to mention about the multicast IP addressing is that as we do have unicast public and private IP addresses, we also have the same in multicast. IANA has reserved the subnet to be used for multicast in our local networks, that means everything between – is safe to use in our networks for multicast.


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