Let’s examine how computers share data inside network.
Special type of software, which called network protocols, is responsible for information transferring over network. This software describes rules of communication machines. TCP/IP (Transmission Control Protocol) is used to data exchanging in global Internet. TCP/IP is actually composed of many different protocols among which you can find:
- HTTP is hypertext data transferring protocol which is used by web servers and web browsers. You can view numerous sites in the Internet by using this protocol.
- FTP protocol is used to network files transferring.
- SMTP is e-mail protocol.
- IP is protocol for data transferring which based on network addressing system.
Last protocol is what we would talk about.
For that would be computers, routers, and other electronic devices could exchange information in the Internet or through any network, they must all have unique personal number (identification code) which called IP address (Internet Protocol Address). Devices can identify each other and determine, where request came from and where the data should be communicated, by using this address.
Nowadays, fourth version of IP Protocol (IPv4) is used to route data packets in the Internet. IP address in this protocol is 32bit number. In the binary system, which used by computers, such a number consists of zeros and ones and has 32 characters. As you understand, for people it’s hard to interpret binary system and we translate it to decimal. For example, we can translate 11000000101010000000000100000001 to 192.168.1.1. Address 192.168.l.l is used as example. There are a lot of variants of router’s IP address. Usually, 192.168.1.1 is used by Zyxel, Asus, ZTE and NetGear. Total number of unique IP addresses, which using IPv4, is 4 228 250 625. This figure looks impressively, but there aren’t enough IP addresses for all global network users. Nowadays, the Internet connection is available not only for computers, laptops and smatphones, but also for coffee maker, TV and other devices.
A global exhaustion of IPv4 addresses was predicted long ago, so today some technologies are used to spend IPv4 more efficiently. We would focus only on principle of dynamic and private (internal) IP addresses, understanding which is important for the configuration of any router.
Usually, static address is assigned to device by user, but dynamic IP address is assigned to the node automatically, when you connect to network for a limited period of time (as example, one session connection to the Internet). IP addresses are automatically distributed by special DHCP Protocol (Dynamic Host Configuration Protocol). Let’s see how this works in practice.
Imagine that provider has a free pool of IP addresses. If user connects any device to his network, provider gets network address from DHCP server list. After user logs off from network, IP address returns into the list and can be reissued to another client. So, it helps to increase efficiency of addresses using and to organize access to the Internet with one address from many devices, but only one by one.