Multicast Address Space (Large Block Assignments as per RFC 5771)


Large Block Assignments as per RFC 5771

Address Range Size Designation General Description
224.0.0.0 – 224.0.0.255 (/24) Local Network Control Block Protocol control traffic that is not forwarded off link (local network only.)
224.0.1.0 – 224.0.1.255 (/24) Internetwork Control Block Used for protocol control traffic that MAY be forwarded through the Internet such as NTP.
224.0.2.0 – 224.0.255.255 65024 AD-HOC Block I Assigned by IANA for needs that don’t fit in the first two categories. These addresses MAY be routed through the Internet.
224.1.0.0 – 224.1.255.255 (/16) Reserved
224.2.0.0 – 224.2.255.255 (/16) SDP/ SAP Block Used for SDP (Session Description Protocol) and SAP (Session Announcement Protocol) only.
224.3.0.0 – 224.4.255.255 (2 /16s) AD-HOC Block II Assigned by IANA for needs that don’t fit in the first two categories. These addresses MAY be routed through the Internet.
224.5.0.0 – 224.255.255.255 (251 /16s) Reserved
225.0.0.0 – 231.255.255.255 (7 /8s) Reserved
232.0.0.0 – 232.255.255.255 (/8) Source-Specific Multicast Block SSM [RFC4607] is an extension of IP Multicast in which traffic is forwarded to receivers from only those multicast sources for which the receivers have explicitly expressed interest and is primarily targeted at one-to-many (broadcast) applications.
233.0.0.0 – 233.251.255.255 16515072 GLOP Block Addresses in the GLOP Block are globally-scoped, statically-assigned addresses. The assignment is made, for a domain with a 16-bit Autonomous System Number (ASN), by mapping a domain’s autonomous system number, expressed in octets as X.Y, into the middle two octets of the GLOP Block, yielding an assignment of 233.X.Y.0/24. The mapping and assignment is defined in [RFC3180].  Domains with a 32-bit ASN MAY apply for space in AD-HOC Block III, or consider using IPv6 multicast addresses.
233.252.0.0 – 233.255.255.255 (/14) AD-HOC Block III Assigned by IANA for needs that don’t fit in the first two categories. These addresses MAY be routed through the Internet.
234.0.0.0 – 238.255.255.255 (5 /8s) Reserved
239.0.0.0 – 239.255.255.255 (/8) Administratively Scoped Block Addresses in the Administratively Scoped Block are for local use within a domain and are described in [RFC2365].

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