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A full duplex.

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Communication is established.

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UDP is another protocol of transport layer Layer four used primarily for establishing low latency and

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loss, tolerating connections between applications on the Internet.

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TCP has emerged as a dominant protocol used for the bulk of internet connectivity owing to its services

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for breaking large data sets into individual packets, checking for and resending lost packets and reassembling

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packets into the correct sequence.

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But these additional services come at a cost in terms of additional data overhead and delays called

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latency.

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In contrast, UDP just sends the packets, which means that it has a much lower bandwidth overhead and

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latency, but packets can be lost or received out of order as a result, owing to the different paths

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individual packets traverse between sender and receiver.

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So UDP uses a simple connectionless communication model with a minimum of protocol mechanism.

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It has no handshaking dialogues and thus exposes the user's program to any unreliability of the underlying

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network.

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There is no guarantee of delivery, ordering or duplicate protection.

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UDP is suitable for purposes where error checking and correction are either not necessary or are performed

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in the application.

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UDP is an ideal protocol for network applications in which perceived latency is critical, such as gaming

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voice and video communications, which can suffer some data loss without adversely affecting perceived

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quality.

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In addition, since its transaction oriented suitable for simple query response protocols such as the

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domain name system or the network time protocol, the UDP header is pretty simple.

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It consists of four fields, each of which is two bytes 16 bits.

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The use of the fields checksum and source port is optional in IPV four.

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Are you surprised to hear that the source port is optional?

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But don't be because as you know, UDP packet does not expect to get a reply in general.

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And again, since UDP doesn't care about the errors, the checksum field is again optional.

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Source port identifies the sender's port and the destination port identifies the receiver's port as

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well.

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And the length field specifies the length of the UDP header and data in bytes.

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So now's a good time to compare the two protocols UDP and TCP.

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As a brief summary.

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Most services on the internet use either TCP or UDP, which are carried end to end across the network

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using IP, either IPV four or IPV six.

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The transmission control protocol, TCP and user datagram protocol UDP are very different.

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TCP is a connection oriented protocol which tries to ensure reliable in-order delivery of packets.

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If packets are lost, TCP automatically retransmits them if they arrive out of order.

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TCP will resequence them before handing them up to an application.

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UDP is connectionless.

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The UDP software makes no attempt to associate streams of packets together.

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So as far as UDP is concerned, each packet is completely independent, unrelated to other packets.

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No attempt is made by UDP for retransmission or resequencing.

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If a packet is lost via UDP, it's up to the higher layer application to resend it.