Multicast Addressing

The Internet Assigned Number Authority (IANA) assigned IP Class D space for multicast addressing –

This includes the range to

Address RangeDescription – Network Control – Control – 1 – – – 2 – – – Specific Multicast – – hoc 3 – – Scoped
Multicast ranges and their definitions

Local Network Control (

Addresses in this range are considered not to be forwarded out of a broadcast domain. They are used for protocol control traffic such as all hosts in the subnet,, all routers in the subnet,, and all PIM routers,

Internetwork Control (

Addresses in the internetwork control block may be forwarded across broadcast domains, and even across the internet. Examples of protocols that may use the internetwork control range are NTP,, Cisco RP Announce,, and Cisco RP Discovery,

Source Specific Multicast (

The range is used by SSM. Source Specific Multicast is an extension to PIM as part of RFC 4607. SSM will forward traffic to receivers from only multicast sources that the receivers that have explicitly requested the multicast source.


Addresses in the GLOP are scoped statically assigned addresses. They are made for domains with a 16-bit AS number by mapping the domains AS number that is expressed in octets as X and Y into the middle two octets of the GLOP block (233.X.Y.0/24)

Domains with 32 bit numbers can utilise space in Ad Hoc 3 or utilise IPv6 multicast addressing.

Administratively Scoped Block (

These addresses are specified in RFC2365 and are limited to a local group or organisation. The addresses are similar to reserved IP unicast ranges such as and Network administrators can utilise this range as they please without worry that they will conflict with another organisation on the internet. Even though SSM has been assigned it is not uncommon to see it utilise

Well Known Multicast Addresses

Multicast AddressDescription hosts in subnet routers in subnet OSPF routers OSPF DRs RIPv2 Routers EIGRP Routers PIM Routers and GLBP RP Announce (Auto RP) RP Discovery (Auto RP)
Well known multicast addresses




Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.