Transmission of information over a network

Data consisting of zeros and ones is usually contained in large files. However, the networks will not function properly if the transmission of information over the network will occur with the help of such entire data blocks. At this time, other computers have to wait a long time for their turn. This situation is similar to the exclusive use of the network. In addition, except for monopolistic use of the network, the occurrence of errors can lead to the need to retransmit the entire large data block.

However, the networks will not function properly if the transmission of information over the network will occur with the help of such entire data blocks

To quickly transfer information over the network without wasting time waiting, the information is divided into small controllable blocks containing all the necessary information for their transmission. These blocks are called packets. The term packet refers to a unit of information transmitted between network devices as a whole.

When the data is divided into packets, the network operating system adds special control information to each packet, which ensures the transmission of information on the network in small blocks, the collection of information in a certain order (when they are received), and checking for errors (after assembly).

The components of the package are grouped into three sections: header, data and trailer.

The heading includes:

  • A signal that a packet is being transmitted,
  • Source address,
  • Address of the recipient,
  • Information that synchronizes the transmission.

For most networks, the packet size is from 512 bytes to 4 KB.

The content of the trailer depends on the protocol connection (the protocol is a set of rules or standards for communication and information exchange between computers). Most often the trailer contains information for error checking, called redundant cyclic code (Cyclical Redundancy —heck, —R—). CRC is the number obtained as a result of mathematical transformations of package data and source information. When the packet reaches its destination, these conversions are repeated. If the result is the same as the CRC, the packet is accepted without errors. Otherwise, the transmission is repeated.

The format and size of the package depend on the type of network. The maximum packet size determines the number of packets that will be created by the network operating system to transfer information over the network in the form of a large data block.

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