IP Address Classification

Class 5 IP address:

IP address classification	First byte range	Fixed highest bit	network bit	network number	host bit	host number
a	0~127	0	8	126 (0 and 127 special purpose)	 	16777214 (2^24-2
b	128~191		16	2^14	16	2^16-2
c	192~223		24	2^21	8	2^8-2 
d	224~239	1110	multicast address	 		 
E	240~255	11110	Reserved for experimental use

Special IP Address：

special address	network ID	host ID	source address using		note
This network's host	all 0	all 0	can	cannot be	When the bootstrapper is executed, but its IP is not known. Use this
A host of this network	all 0	host ID	cannot be	can	 
network address	network ID	all 0	can	can	 
Direct broadcast address	network ID	All 1	cannot be	can	Specific network all hosts. That is, full-screen broadcast
limited/local broadcast address	all 1	All 1	cannot be	can	 
Loopback address	127	No matter what the number	Can	Can

the difference between multicast and broadcast：
Broadcast-This means sending messages to multiple computers in the subnet at the same time, and the computers in all subnets can receive messages from the sender. Each broadcast message includes a special IP address. There are two types of broadcast message addresses: Direct broadcast address and local broadcast. Direct Broadcast address: network number is normal. Host number 1 to all hosts in the target network to send the text broadcast address: Network + host number 1 to all hosts in the local network to send messages, the router does not forward MulticastBroadcast mode of communication although it is possible to achieve a one-to-many communication needs, but. Because the broadcast is to send messages to all computer users in the subnet, there is no purpose, not only to add the network transport burden, and resource consumption is high. The appearance of multicast. Better to conquer the problem.

Multicast is also called multicast. Multicast is the sending of messages from one computer to a subset of computers selected in the network or across the network, which is sent to computers that increase the specified multicast group . The multicast group is open, and each computer can be added to the multicast group at any time by the program, and can leave at any time.
Class D address first byte 224~239 224.0.0.0 ~ 224.0.0.255 for reserved multicast address (Permanent group address) Example: 224.0.0.0 to 224.0 .0.255 is the reserved address

224.0.0.1 indicates that all multicast groups in the subnet

224.0.0.2 represent all routers in

the subnet

224.0.0.5 that the OSPF router

224.0.0.6 represents OSPF specifies

that the router

224.0.0.12 represents dhcpserver

224.0.1.0 ~ 224.0.1.255 Public multicast address (for Internet) 224.0.2.0 ~ 239.255.255.255 Local Management multicast address (specific local scope is valid)
private Network IPSuppose an organization does not need to be connected to the Internet. But at the same time execute TCP/IP, select the private network Ip,internet router does not forward the destination address is the private network address of the packet.

Private network IP Address

Type	Network address	Number of networks
A	10.x.x.x	1
B	172.16.x.x ~ 172.31.x.x	16
C	192.168.x.x ~ 192.168.x.x	256

own active Private IP address(APIPA Auto Private IP Address) scope: 169.254.0.0 ~169.254.255.255 169.254.x.x When a dynamic address cannot be obtained, the address is not used on the Internet as a temporary host address. For example, if the open DHCP gets the mobile IP, however, this allocates the IP, then the network may be faulted.

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IP Address Classification