Difference between revisions of "UDP"

From Second Life Wiki
Jump to navigation Jump to search
(Major revision to UDP)
(Updated)
Line 1: Line 1:
Usergram Data Protocol
'''UDP''' is an initialism for '''Usergram Data Protocol'''


[http://www.faqs.org/rfcs/rfc768.html UDP] is the unreliable cousin of [http://www.faqs.org/rfcs/rfc793.html TCP] on TCP/IP networks.
UDP is the unreliable cousin of TCP on TCP/IP networks.   UDP does not guarantee delivery, or reliability, and because of this it is ideal for services such as video streaming.  For a service such as video streaming, reliability and guarantee of delivery are not the highest concern; instead it is only important that the video is transmitted from the server to ''all'' the clients, without a care for 'expired' packets.  What seperates the two protocols is that TCP requires the client to inform the server that it received all of the packets sent, and also to re-request packets that arrived corrupted or did not arrive at all.  As a result of this there is additional overhead for TCP when comparing TCP to UDP, and it is this lack of additional overhead (combined with other factors) that makes UDP superior to TCP in streaming scenarios.   
 
==UDP Summary==
UDP does not guarantee delivery, or reliability, and because of this it is ideal for services such as video streaming.  For a service such as video streaming, reliability and guarantee of delivery are not the highest concern; instead it is only important that the video is transmitted from the server to ''all'' the clients, without a care for 'expired' packets.  What seperates the two protocols is that TCP requires the client to inform the server that it received all of the packets sent, and also to re-request packets that arrived corrupted or did not arrive at all.  As a result of this there is additional overhead for TCP when comparing TCP to UDP, and it is this lack of additional overhead (combined with other factors) that makes UDP superior to TCP in streaming scenarios.   
 
===DNS===
UDP also drives DNS communication, translating Internet addresses such as http://'''www.secondlife.com''' into IP addresses computers understand, such as http://'''66.150.244.168'''/ .


For more general information on UDP, please


==Second Life and UDP==
==Second Life and UDP==
With the exception of textures, Linden Lab's Second Life uses UDP as it's primary mode of communication with it's servers.  Little information exists about Second Life's usage of UDP, hopefully with more information soon to come.
For more information on TCP and UDP, please see their respective definition documents.  (Note that these protocols use the services provided by the IP layer underneath them, be it IPv4 or IPv6.)


[ftp://ftp.rfc-editor.org/in-notes/rfc768.txt User Datagram Protocol]
Second Life uses UDP the primary mode of communicating small bits of real-time data between viewers and simulators (e.g. keystrokes and object updates). See [[Protocol]] for more information about how this works.


[ftp://ftp.rfc-editor.org/in-notes/rfc793.txt Transmission Control Protocol]
== Further reading ==
[http://www.faqs.org/rfcs/rfc768.html Official UDP specification (RFC 768)]
*  [http://www.faqs.org/rfcs/rfc793.html Official TCP specification (RFC 793)]
*  [http://en.wikipedia.org/wiki/UDP Wikipedia article on UDP]

Revision as of 11:00, 23 June 2007

UDP is an initialism for Usergram Data Protocol

UDP is the unreliable cousin of TCP on TCP/IP networks. UDP does not guarantee delivery, or reliability, and because of this it is ideal for services such as video streaming. For a service such as video streaming, reliability and guarantee of delivery are not the highest concern; instead it is only important that the video is transmitted from the server to all the clients, without a care for 'expired' packets. What seperates the two protocols is that TCP requires the client to inform the server that it received all of the packets sent, and also to re-request packets that arrived corrupted or did not arrive at all. As a result of this there is additional overhead for TCP when comparing TCP to UDP, and it is this lack of additional overhead (combined with other factors) that makes UDP superior to TCP in streaming scenarios.

For more general information on UDP, please

Second Life and UDP

Second Life uses UDP the primary mode of communicating small bits of real-time data between viewers and simulators (e.g. keystrokes and object updates). See Protocol for more information about how this works.

Further reading