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IP-surveillance Concept
The whole idea of IP-surveillance based on the
rapid development of Internet and computer network. Internet
links all the computer worldwide, user can easily get
information by accessing Internet.
In the surveillance industry, we also use
Internet to share records of DVRs, enabling user can
monitor and access records in the DVR. With our advanced
technology, user can even control the DVR with a ease.
TCP/IP
Infrastructure
The IP Address and Classes
Hosts and networks
IP
addressing is based on the concept of hosts and networks.
A host is essentially anything on the network that is capable of
receiving and transmitting IP packets on the network, such as a
workstation or a router. It is not to be confused with a server:
servers and client workstations are all IP hosts.
The
hosts are connected together by one or more networks. The
IP address of any host consists of its network address plus its own
host address on the network. IP addressing, unlike, say, IPX
addressing, uses one address containing both network and host
address. How much of the address is used for the network portion and
how much for the host portion varies from network to network.
IP addressing
An IP
address is 32 bits wide, and as discussed, it is composed of two
parts: the network number, and the host number [1, 2,
3]. By convention, it is expressed as four decimal numbers separated
by periods, such as "200.1.2.3" representing the decimal value of
each of the four bytes. Valid addresses thus range from 0.0.0.0 to
255.255.255.255, a total of about 4.3 billion addresses. The first
few bits of the address indicate the Class that the address belongs
to:
| Class |
Prefix |
Network Number |
Host Number |
| A |
0 |
Bits 0-7 |
Bits 8-31 |
| B |
10 |
Bits 1-15 |
Bits 16-31 |
| C |
110 |
Bits 2-24 |
Bits 25-31 |
| D |
1110 |
N/A |
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| E |
1111 |
N/A |
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The bits are labeled in network order, so that
the first bit is bit 0 and the last is bit 31, reading from left to
right. Class D addresses are multicast, and Class E are reserved.
The range of network numbers and host numbers may then be derived:
| Class |
Range of Net
Numbers |
Range of Host
Numbers |
| A |
0 to 126 |
0.0.1 to
255.255.254 |
| B |
128.0 to 191.255 |
0.1 to 255.254 |
| C |
192.0.0 to
254.255.255 |
1 to 254 |
Any address starting with 127 is a loop back
address and should never be used for addressing outside the host. A
host number of all binary 1's indicates a directed broadcast over
the specific network. For example, 200.1.2.255 would indicate a
broadcast over the 200.1.2 network. If the host number is 0, it
indicates "this host". If the network number is 0, it indicates
"this network" [2]. All the reserved bits and reserved addresses
severely reduce the available IP addresses from the 4.3 billion
theoretical maximum. Most users connected to the Internet will be
assigned addresses within Class C, as space is becoming very
limited. This is the primary reason for the development of IPv6,
which will have 128 bits of address space.
What is Network DVR? For more
information:
Network DVR Whitepaper
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