Multicasting routing

In essence, IP multicasting is a function of the IP address in use by a particular
“multicast group.” If a user wants to send an audio presentation to a variety of distributed
hosts simultaneously, then that user would send the data to an IP address
that was associated with a particular multicast group. Any hosts that were listening
for traffic destined for that IP address would then receive the data and process
it accordingly, while other hosts would simply ignore it.
The application protocol used for such a feed could be a RealAudio stream sent as
a bunch of UDP messages over IP. These messages would not look any different
from the same data being sent to a single destination system or to the local broadcast
address. The only difference between the multicast datagrams and their unicast
or broadcast equivalents would be the destination IP address in use with
those datagrams: the unicasts would point to a specific destination system, the
broadcasts would point to all hosts on the local network, and the multicasts would
point to a group address.
In the IP world, multicast group addresses are known as Class D addresses and
include all of the IP addresses in the range of 224.0.0.0 through 239.255.255.255.
Each of the individual addresses in this range refer to specific multicast groups,
many of which are associated with a specific application or service.
 

• IP Troubleshooting
• Introduction to IP Multicasting
• IP Multicasting and IGMP Specifications
• Debugging ARP Problems
• IP Datagrams/IP Packets
• Application Protocols Communicate Over IP
• udp protocol
• tcp ip protocol
• Application Protocols (HTTP, SMTP, etc.)
• The Transport Protocols (TCP and UDP)
• The Internet Protocol
• Comparing TCP/IP to the OSI Reference Model
• OSI Reference Model
• TCP/IP’s Architecture
• Introduction to TCP/IP
• TCP segment
• Messages
• IP packet
• IP datagram