Udp
DerekAustin26
Member Posts: 275
in CCNA & CCENT
Can anyone explain what a UDP is used for and why we need it? (yes i've read about it... But im looking for someone who could explain this in lamens terms)
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dynamik
Banned Posts: 12,312 ■■■■■■■■■□
For data that isn't important, such as a real-time audio and video. There's no point in trying to resend any data that doesn't make it because it's usefulness has already passed. -
kriscamaro68
Member Posts: 1,186 ■■■■■■■□□□
Like dynamik said its for info that cant be re-transmitted. If you are on a voip network and talking and a packet drops then you cant resend that packet it would interrupt the conversation. Plus that point in time has already passed and the need for that info is no longer useful. Also video transmitted live is the samething it would try to resend a packet that is no longer needed in that video feed if TCP where used. UDP eliminates the need for handshake between the two points and just sends data through as it comes. -
Morty3
Member Posts: 139
Used when speed is more important then secure delivery. Streaming, gameing.
Also important point from above, where there is no repoint in sending becouse that data is useless because it should have been used already.CCNA, CCNA:Sec, Net+, Sonicwall Admin (fwiw). Constantly getting into new stuff. -
networker050184
Mod Posts: 11,962 Mod
For data that isn't important, such as a real-time audio and video. There's no point in trying to resend any data that doesn't make it because it's usefulness has already passed.
Thats the first time I have heard someone call real time audio not important
An expert is a man who has made all the mistakes which can be made. -
dynamik
Banned Posts: 12,312 ■■■■■■■■■□
networker050184 wrote: »Thats the first time I have heard someone call real time audio not important
Hehe, you know what I mean
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networker050184
Mod Posts: 11,962 Mod
Yeah I know what you mean just giving you a little trouble
An expert is a man who has made all the mistakes which can be made. -
dtlokee
Member Posts: 2,378 ■■■■□□□□□□
UDP is typically used where you don't want or can't have the overhead of setting up a TCP session.
All broadcast traffic is UDP, this makes sense because the device sending the packets is trying to communicate to a large number of hosts.
Real time audio (RTP used in voice networks) will use UDP as it's transport becasue in that case it would be worse to the connection to try and wait for a TCP retransmission in the case of lost packets.
Also don't assume that all UDP connections are not reliable, the application itself can also provide for error detection and recover like TFTP will. In that case the TFTP client and server will exchange acknowledgements making it reliable, even though they are using UDP. It's an important point to understand, the APPLICATION (Application/presentation/session layers of the OSI model) will provide the reliable connection, not the TRANSPORT (UDP on the transport layer)The only easy day was yesterday! -
kalebksp
Member Posts: 1,033 ■■■■■□□□□□
UDP is also generally used with VPNs and other tunneling methods because the encapsulated traffic will provide reliability if necessary. (You can have TCP VPNs, but that will cause poor performance due to both the encapsulated packets and the encapsulating packets being retransmitted when one is dropped.)
