Multicast IP Addressing
Multicast Addresing is the addressing that is used for Multicast Groups. We can divide Multicast Addressing into two:
- IPv4 Multicast Addressing
- IPv6 Multicast Addresing
These addresses identifies the destination of Multicast traffic. In other words, they show the Multicast Groups. The Multicast Source adresses uses normal addresses.
For example for IPv4, Multicast Group Addresses and the Multicast Source
- 0.0.0 – 188.8.131.52 Multicast Group Address Range
- 0.0.0 – 184.108.40.206 Source Address Range
Let’s see these both of these Multicast Addresses.
IPv4 Multicast Addresses
IPv4 Multicast Addresses are the D Class IPv4 addresses between 220.127.116.11 and 18.104.22.168. These address blocks are used for different Multicast purposes. IANA manages these address blocks
There are different sub ranges in Multicast Group Addresses. Acording to the IANA records, these Multicast Group Addresses are :
- Local Network Control Block (22.214.171.124 – 126.96.36.199)
- Internetwork Control Block (188.8.131.52 – 184.108.40.206)
- AD-HOC Block I (220.127.116.11 – 18.104.22.168)
- RESERVED (22.214.171.124-126.96.36.199)
- SDP/SAP Block (188.8.131.52-184.108.40.206)
- AD-HOC Block II (220.127.116.11-18.104.22.168)
- RESERVED (22.214.171.124-126.96.36.199)
- DIS Transient Groups 188.8.131.52-184.108.40.206)
- RESERVED (220.127.116.11-18.104.22.168)
- Source-Specific Multicast Block (22.214.171.124-126.96.36.199)
- GLOP Block (188.8.131.52-184.108.40.206)
- AD-HOC Block III (220.127.116.11-18.104.22.168)
- Unicast-Prefix-based IPv4 Multicast Addresses (22.214.171.124-126.96.36.199)
- Scoped Multicast Ranges (Reserved) (188.8.131.52-184.108.40.206)
- Scoped Multicast Ranges (Organization-Local Scope) (220.127.116.11-18.104.22.168)
For you network certification studies and real life, you ned to know some of these ranges. But as a view, you can use the below table.
In the certification documents generally the below address ranges are shown. So, remembering these blocks can be useful.
- Permanent Multicast (Local Network and Internetwork Control) à0.0.0 – 22.214.171.124
- Source-Specific Multicast (SSM) à0.0.0 – 126.96.36.199
- GLOP Block à0.0.0 – 188.8.131.52
- Scoped Multicast (Private) à0.0.0–184.108.40.206
Permanent Multicast addresses are between 220.127.116.11 and 18.104.22.168. They are used for Routing Protocols or for other low level protocols.
Local Network Control Block Range is the addresses between 22.214.171.124 and 126.96.36.199. Local Network Control Block addresses use TTL value 1. So, multicast routers should not forward any multicast data with destination address.
Some of the example addresses in this group are given below:
- 188.8.131.52 All Hosts
- 184.108.40.206 All Multicast Routers
- 220.127.116.11 DVMRP Routers
- 18.104.22.168 OSPF Routers
- 22.214.171.124 OSPF Designated Routers
- 126.96.36.199 RIP2 Routers
- 188.8.131.52 IGRP Routers
- 184.108.40.206 DHCP Server/Relay Agent
- 220.127.116.11 All PIM Routers
- 18.104.22.168 VRRP
If you want to reach all Hosts on the network, you need to use 22.214.171.124,
If you want to reach all Routers on the network, you need to use 126.96.36.199,
If you want to reach all OSPF Routers on the network, you need to use 188.8.131.52,
If you want to reach all OSPF DRs on the network, you need to use 184.108.40.206,
If you want to reach all EIGRP Routers on the network, you need to use 220.127.116.11,
If you want to reach all PIMv2 Routers on the network, you need to use 18.104.22.168,
If you want to reach all ISIS Routers on the network, you need to use 22.214.171.124-21,
If you want to reach all IGMPv3 Devices on the network, you need to use 126.96.36.199.
Internetwork Control Block Range is the addresses between 188.8.131.52 and 184.108.40.206. They use a TTL value higher than 1.
- 220.127.116.11 VMTP Managers Group
- 18.104.22.168 SGI-Dogfight
- 22.214.171.124 Rwhod
- 126.96.36.199 NSS-Name Service Server
- 188.8.131.52 SUN NIS+ Information Service
- 184.108.40.206 Any Private Experiment
- 220.127.116.11 DVMRP on MOSPF
- 18.104.22.168 Mtrace
- 22.214.171.124 RSVP-encap-1
- 126.96.36.199 RSVP-encap-2
- 188.8.131.52 Cisco-RP-Announce
- 184.108.40.206 Cisco-RP-Discovery
- 220.127.116.11 Mbone-VCR-Directory
- 18.104.22.168 Tibco Multicast1
- 22.214.171.124 Tibco Multicast2
Source-Specific Multicast (SSM) Range is the Multicast addresses between 126.96.36.199 and 188.8.131.52. These multicast addresses are used for Source-Specific Multicast (SSM) Applications and Protocols. SSM provide an efficient multicast routing with its mechanism. Because, with SSM, host can select the Multicast Group that it get traffic.
GLOP Block Range is the Multicast addresses between 184.108.40.206 and 220.127.116.11.These Multicast address block can be used by the companies that has registered Autonomous System Number (ASN). With this address block, each company can have up to 256 Global Multicast Addresses.
Scoped Multicast Range are the Private block of Multicast Address Range between 18.104.22.168 and 22.214.171.124. They are like Private IP address and they can be used only within the network, not globally on internet.
You can reach the whole Multicast addresses assigned by IANA below: