Vyatta Network OS Documentation

Learn how to install, configure and operate the Vyatta NOS, which helps drive our virtual networking & physical platforms portfolio.

Multicast addresses

For IPv4, addresses in the range 224.0.0.0 to 239.255.255.255 are reserved for multicasting. In the classful addressing system, this is registered as class D. In the Classless Inter-Domain Routing (CIDR) addressing model, the prefix of this group is 224.0.0.0/4.

Within the IPv4 multicast range, address assignments are specified in RFC 5771, IANA Guidelines for IPv4 Multicast Address Assignments. Multicast address assignments lists a summary of these assignments. Note that, of these addresses, the network address 224.0.0.0 is guaranteed not to be assigned to any group.

Table 1. Multicast address assignments
AddressesUsage

Link Local Scope

224.0.0.1 All systems on this subnet
224.0.0.2 All routers on this subnet
224.0.0.13All PIM routers address group

Global Scope

224.0.1.0 to 238.255.255.255 Allocated for multicast traffic across the Internet. SSM reserves the range 232.0.0.0/8. The addresses 224.0.1.39 and 224.0.1.40 are used for Auto-RP negotiation. You can assign the remaining IP addresses to your ISM applications.

Administrative Scope (AS)

239.0.0.0/8Allocated for organizations that own an AS number to multicast across the Internet. The AS number of the organization is embedded in the second and third octets of the multicast IP address. For example, AS64501 is 0xFBF5, with FB and F5 (or 251 and 245 in decimal) representing the second and third octets of the IP address, respectively. The resulting subnet 233.251.24.0 is globally reserved for AS64201 to use. These addresses are called GLOP addresses.

For IPv6, multicast addressing is specified in RFC 3513, IP Version 6 Addressing Architecture. In essence, IPv6 multicast addresses are derived from the FF00::/8 prefix.