Multicast Basics

Till now we discussed about, Multicast and about advantages and disadvantages. Now let’s see some Multicast basics. Which is very important in real time to deal with multicast , we will discuss about Multicast address ranges and reservations.

Basics:

A single host can join multiple Multicast group at same time. ( We can open as many applications on our PC , In same time it will access different multicast groups)

The source will not come to know, who are receivers / host.

Multicast Address Range

• The range of Multicast IP address is Class D – 224.0.0.0 – 239.255.255.255
• Address assignments from within this range are specified in RFC 5771.
• In this range, 224.0.0.1 – 224.0.0.255 is reserved for Network local (communication) address.
• 232.0.0.0/8 is reserved for Source-Specific Multicast
• 233.0.0.0/8 is reserved for GLOP addressing
• 239.0.0.0/8 is Private range for Multicast address, AKA Administratively scoped address.
•  The First four bits of Multicast IP address is 1110.

Well known Multicast addresses - 

224.0.0.5 – All OSPF routers

224.0.0.6 – All OSPF DR’s

224.0.0.9 – All RIPv2 routers

224.0.0.10 – All EIGRP/ IRMP routers

224.0.1.1 – NTP

224.0.0.1 – All Multicast hosts ( If you ping this IP address, The multicast capable host will reply)

224.0.0.2 – All Multicast Routers

224.0.0.4 – All DVMRP Routers

224.0.0.13 – All PIM Routers

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