Multicast P2P

1. Peer-to-Peer technology Peer-to-Peer technology: all clients can send messages to all other clients in the group.

All clients in the multicast group have equal rights. Every client has the ability to exchange messages with other clients in the group

Image 1: Every client can exchange messages with other clients in the group

The IP system supports the multicast group following peer-to-peer , allowing all devices on the network to send and receive packets whose destination is the multicast group address. Some coding factors are to prevent anonymous clients from receiving data in the group but there is still no way to receive authentication from clients about data

1. Group Address - IP Multicast group address

• IP Multicast group address is used by sender and receiver to send and receive data.

• Sender uses the group address as the destination address for the packets.

• Receiver uses the group address to notify the network they have received packets from the group

For example, the group address is 239.1.1.1. Sender will send data to the destination address which is 239.1.1.1. Receiver will notify the network that it has received the data sent from the address 239.1.1.1. Receiver must "join" to the address 239.1.1.1.

• Internet Assigned Numbers Authority (IANA) considers the range of Class D addresses as Multicast addresses. This group address spans a range from 254.0.0.0 to 239.255.255.255. This address range is only used as a group address or a destination address in IP Multicast. The source address of multicast packets is always the unicast address.
• Routers and switches must have a method to distinguish multicast traffic from unicast traffic or broadcast traffic. This is done by assigning IP address, using Class D addresses from 224.0.0.0 to 239.255.255.255 for multicast only. Devices can quickly filter out multicast addresses by reading the 4 bits to the left of an address. These four bits of a multicast address are always 1110. Unlike the Class A, B and C address ranges, this class D address has no subnetting process. Therefore, there are 2 powers of 28 multicast group addresses taken from this class D. Multicast addresses represent a group, not a host.
• In particular, the address range from 224.0.0.0 to 224.0.0.255 is used for protocols on the network. These network packets are not forwarded by routers. They are placed in local area networks (LAN) segments and have Time To Live** (TTL)**.

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