Windows Server 2003 DHCP full Raiders (iii)

Configure multicast scopes

1. Introduction to multicast scopes

Multicast is a single point to multiple points of information communication. In the network, unicast, broadcast and multicast 3 mechanisms can be used for single point to multicast, in which multicast is the most suitable choice.

(1) unicast. Using unicast to carry out single point to multi point information, it is necessary to send the information to each receiving node separately from the sending node. The disadvantage of this mechanism is that there is a large amount of duplication of network traffic and some additional overhead incurred by maintaining a list of unicast receiving nodes.

(2) broadcast. Using broadcasts, you can send information that needs to be delivered in a single packet. The advantage is that it uses only a single packet and does not incur additional overhead by maintaining a list of receive nodes. But its flaws are obvious, for broadcast packets, any node in the network must be received and processed, regardless of whether the node really needs to receive this packet, which will disrupt all nodes of the network, and broadcasts cannot be forwarded through routers or across physical subnets, so broadcast packets, Although you can reach everyone on the local subnet, you cannot reach anyone on other subnets, especially the Internet.

(3) Multicast. Use multicast to send information that needs to be delivered in a single packet. Because only a single packet is used, avoids the large amount of repetitive communication that is generated by using unicast, nor does it incur additional overhead because of maintenance of nodes, which do not send information to all nodes as broadcast packets do, but only to real nodes that need to receive the packet. As a result, multicast traffic does not disrupt nodes that do not need to receive packets, and routers support multicast forwarding, which can forward multicast packets to all networks, ensuring that all destination nodes for a single point of multicast are received.

2. Multicast address

Multicast addresses the IP addresses that can be used in IP multicasting from 224.0.0.0 to 239.255.255.255.

Common well-known IP multicast addresses:

224.0.0.0: Basic address (reservation)

224.0.0.1: "All hosts" multicast groups, containing all hosts on the same network segment.

224.0.0.2: "All routers" multicast groups that contain all routers on the same network segment.

224.0.0.9:ripv2 A packet address that is used to send RIP routing information to all RIPV2 routers on the network segment.

224.0.1.24:wins Server group address that supports automatic discovery and dynamic configuration of replicas of WINS servers.