TCP & UDP

Question

Comments

only multiplexing for both

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Note:

UDP will certainly check the packet for error using checksum, but if there is error in the packet

during transmission it will simply drop the packet. there is no recovery process for packet

having error like re-transmission TCP..

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UDP does not support error control. Inclusion of checksum field is optional. It detects the error , but it won't correct it !

In UDP only error detction is done , no error correction

Answer 1

2 and 3  are correct.
TCP and UDP both provides error control (although UDP uses only Checksum) and multiplexing.

Comments

If UDP uses check sum then why is it a Unreliable.?

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B/C Checksome for UDP is Optional not always used.

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How error controlled by UDP?

If checksum does not match it will discard the packet silently and there are no retransmission.

So how error is controlled?

Answer 2

When we look clearly the format of the TCP we see windows size but there is no such option in UPD so option A is wrong.

In TCP and UDP error control is common in both but suppose any erro happen with packet then there exist retransmission facility in TCP but UDP will lynce it. So option B wrong.

Now Multiplexing and demultiplexing is common for both.

Reliable transmission always happen with the TCP but not with UDP bcz TCP is connection oriented and UDP is connectionless so no guarantee of reliabilty.

Option-b

Answer 3

ONIL MULTIPLEXING IS DONE