UPD in modern online media is a mark
, meaning that the news or article was supplemented in connection with the changed situation after its writing. These three letters are a reduction from the English wordUpdate.
(update, adjust information). In pursuit of urgent news, some sites write news on the fly, often without checking all the details, so when these most details have to complement or correct the news already written.
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Recall a little about OSI
The modern world is unthinkable without communicating. Tens of millions of devices worldwide are associated with computer networks. And each computer network is organized according to certain standards. Any devices interact on a generally accepted model. OSI , or a basic reference model of interaction of open systems. This model determines the interaction of various network devices at seven levels - Media (These include physical, channel and network) and Host. - (transport, session, presentation and applied). In this article, we will consider the two most common network protocols of the transport level - TCP. и UDP. , examples of their application, as well as compare their characteristics.
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Video: TCP and UDP | What is it and what is the difference?
What is the difference in TCP and UDP?
In general, the transport level protocols are widely used in modern networks. They allow you to guarantee the delivery of the message to the destination, and also save the correct data sequence. At the same time, the protocols have a number of differences, which makes it possible to use their profin, to solve their tasks each.
TCP Protocol (TRANSMISSION Control Protocol) is a network protocol that is "sharpened" under the connection. In other words, before starting data sharing, this protocol is required to establish a connection between two hosts. This protocol is highly reliable because it allows you to lose data when transmitted, requests confirmation of receipt from the receiving party and, if necessary, sends the data again. At the same time, the data packets retain the dispatch procedure, that is, it can be said that data transmission is ordered. The disadvantage of this protocol is a relatively low data transfer rate due to the fact that the performance of reliable and ordered transmission takes longer than in the UDP alternative protocol.
UDP protocol (User Datagram Protocol), in turn, is simpler. To transfer data, it is not necessary to establish a connection between the sender and the recipient. Information is transmitted without preliminary checking the receiving party. This makes the protocol less reliable - when transmitted, some data fragments may be lost. In addition, the ordering of the data is not followed - the inconsistent reception of these by the recipient is possible. But the data transfer rate for this transport protocol will be higher.
Conclusion and visual comparison
We give several main points:
- Reliability : In this case, the TCP protocol will be preferable, by confirming the receipt of data, re-send if necessary, as well as the use of such a tool as a timeout. The UDP protocol does not have such an instrument, and therefore, when receiving, the sent data may not be completely coming;
- Orderly : Again will be preferable to TCP, since this protocol guarantees the transfer of data packets in the order in which they were sent. In the case of UDP, such an order is not respected;
- Speed : There will be a UDP to lead here, since a more heavy TCP protocol will be required more time to set the connection, confirmation, re-sending data, etc. ;
- Data transfer method : In the case of TCP, the data is transmitted streaming, the boundaries of data fragments do not have the notation. In the case of UDP, data is transmitted as a datagram - checking packages for integrity is carried out by the receiving party only in case of receipt of the message. Also, data packets have certain boundary designations;
Comparing both protocols, it is obvious that the TCP protocol is, you can say "sniper". Acted himself, shot, fixed the hit, looking for the next goal. UDP is, rather, "machine gunner" - put out the trunk in the direction of the enemy and began to beat the queues, not too taking care of accuracy. As in the troops, both of these military specialties are important and both of these protocols are important on the Internet. TCP applies where accurate and confirmed data transfer is required - for example, sending photos, or correspondence between users. UDP, in turn, is needed to communicate in a voice format, or when transmitting streaming video, for example, from webcams or IP cameras.
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