Why is UDP needed?

[ericfjchen]

TCP is more safe than UDP. Why is UDP needed?

Thanks

Eric

[Olivier Decorse]

How !
What a big question !
TCP and UDP are so different, that sometimes, the first is better, and sometimes, is is the second.

For example, redirecting syslog to a central server is possible (only) via udp : it is quickly (just a message) and don't have to be secure : if the message don't arrive to the server, it is not so important ...

Olivier.

[Michael Selvesteen_2]

Some advantages:

1.An UDP datagram is used in Network File System (NFS), DNS, SNMP, TFTP etc.

2. It has no handshaking or flow control

3. It not even has windowing capability

4. It is a fire and forget type protocol.

5. Real time application like video conferenicing needs udp (B'coz it's faster)

6.An application can use a UDP port number and another application can use the same port number for a TCP session from the same IP address.

it has it's own advantages other than lack of sequencing, error control and more


RFC 768 describes UDP in detail.

[Eric Antunes]

Hi Eric,

UDP is used, for exemple, by the web listeners in Oracle E-Business Suite...

[Muthukumar_5]

Transmission control protocol is reliable and safer over User Datagram protocol as,

1. Checking aknowledgement
2. Sending steam data's and using policy of "Positive aknowledgement and Retransmission method"
3. Flawless packet transmission
4. Flow controlled data transcation

UDP is needed for,

1. Minimal amount of header informations for every packet
2. Efficient packet transmission
3. Minimal system call usage for operations


see man tcp / udp for this more.

[R. Sri Ram Kishore_1]

Hi Eric,

Take a look at these links:

[broken links removed on <4/7/2017> by Mod]

HTH.

Regards,
Sri Ram

[Dave Olker]

Hi Eric,

Do the above responses answer your questions or is there some other specific information about UDP that you're still looking for?

As stated above, the main reasons why some application implementers (like the original NFS design team) used UDP was because of it's speed and low overhead. As TCP implementations improved over the years, most applications have switched to using TCP but some still offer a UDP variant.

If there is some specific piece of information you're looking for regarding UDP vs. TCP please let me know.

Regards,

Dave

[rick jones]

Why do we need UDP? Because there are applications that do not need, or even want, the in-order, guaranteed notification of failure, byte-stream semantics of TCP.

As for multimedia stuff - they want UDP not because UDP is faster - sometimes UDP isn't really faster - but because they can tolerate the occasional unrecovered packet loss, but cannot tolerate a 500 millisecond or more "hiccup" in the data flow that a TCP retransmission would take.

[ericfjchen]

Thanks for your reply. I would like to update the question. The whole problem is ....why is UDP needed? Why can't a user program directly access IP?
This problem is from Entrance Exam of MIS. I don't know the relation between first and second. Do you have any idea?

[malay boy]

Eric,
You should check "Seven Layer OSI".UDP/TCP is working on transport layer which are layer 4 and IP is working on network layer which are layer 3.
Basically you need to unserstabd the concept of this seven layer.

regards
mB