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Chapter
6
6 NETWORKING OVERVIEW
This chapter will give you a basic instruction on how to set up the DVR for network connection. It is highly recommended
that you have a working knowledge of what a network is and how it works. This will be helpful in completing the networking
process.
6.1 INTRODUCTION TO TCP/IP
TCP/IP is the group of protocols used by the Internet and most Local Area Networks (LANs) throughout the world. In TCP/IP,
every computer or other communications device that is connected to the network has a unique IP address. By doing this
you are giving your device a unique address similar to the address of your house. An IP address is composed of four octets
(numbers in the range of 0 to 255) separated by decimal points. The IP address is used to uniquely identify a host or
computer on the LAN. For example, one computer on a network could have an IP address of 192.168.1.127.
You should never give two or more devices the same exact IP address, but the first three octets of an IP address is often
the same for all computers in the local area network. For example, if a total of 253 computers exist in a single LAN, the IP
addresses could be assigned starting with 192.168.1.x, where x represents a number in the range of 2 to 254. An IP
address could be compared with a telephone number.
6.2 SUBNET MASKS
Each host in a LAN has a subnet mask. The subnet mask is a set of octets that is used to determine which LAN or class it
belongs to. The number 255 is usually used to represent the network address portion of the IP address and a zero is placed
at the end to identify the host portion of the address. Basically the subnet mask tells the devices how the network addresses
are organized, and helps to determine which addresses are local and which are remote (on the other side of the router).
6.3 GATEWAY ADDRESS
Addressees are either local or remote. A gateway address is composed of four octets separated by decimal points. The
gateway address is used to uniquely identify the device on the LAN that has access to the communications links connecting
to other LANs, WANs and/or the Internet (access to the 'remote' addresses).
6.4 VIRTUAL PORTS
A port number represents a "channel" or entryway for network communications. Port numbers allow different computers to
utilize network resources without interfering with each other. Port numbers most commonly appear in network programming,
particularly socket programming. Sometimes, though, port numbers are made visible to the casual user. For example, some
websites on the Internet use a URL like the following:
http://www.sitename.com:8100/
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