Internet Protocol and IP addresses
Internet Protocol (IP) is the simplest protocol that unites individual computers into a global network. Its main task is routing datagrams – determining the route that packets take to network nodes. Each device – your PC, printer, etc. – has an IP-address so that the data gets to the right addressee. So, for example, a file sent to print will not end up on your colleague’s private PC instead of the printer.
The disadvantages of the protocol are its low reliability. It does not detect the fact that a packet is being sent and does not control the integrity of the data. IP just does the forwarding.
To forward packets, it must be determined on which port to send the packet. For this the protocol has its own addressing system. The addresses are either 32-bit (IPv4) or 128-bit (IPv6) addresses. A header and payload are added to the packet before it is sent.
IPv4 is a 32-bit, four-partition system (123.123.123.123). It supports up to 4,294,967,296 addresses and is the default protocol. Its main advantage is simplicity. The disadvantages are the limited address space, also called “address exhaustion”.
IPv6, on the other hand, is a 128-bit address space that provides approximately 2^128 degrees of addresses. The entry format consists of eight partitions, with four 16-character digits written into each partition. The disadvantage of the protocol is the difficulty of network administration. When renting a server or virtual machine at Selectel, IPv4 is issued, but IPv6 addresses can also be requested; in a VMware-based cloud, only IPv4 addresses are issued.
One of the main protocols that works on top of IP is TCP, which is why it is often referred to as TCP/IP. But it is not the only protocol that is part of the Internet protocol.
TCP is an Internet messaging protocol
TCP helps devices on a network exchange messages. It works at layer 4, the transport layer, of the OSI model.
To send information, the original file is broken down into pieces that are sent to the recipient and then reassembled. For example, a person requests a web page, a server processes the request and sends back an HTML page using the HTTP protocol. It, in turn, requests the TCP layer to establish the required connection and send the HTML file. TCP converts the data into blocks and sends it to the TCP layer of the user, where it confirms the transmission.