[Twisted-Python] UDP with multiple connections

[Simon Pickles]

UDP is often used in online gaming, where other methods are employed to 
compensate for its weaknesses, in return for its speed.

 
Phil Mayers wrote:
> On Tue, 2007-10-09 at 21:21 +0100, Simon Pickles wrote:
>   
>> Ok, UDP is new to me, so please be gentle....
>>
>> I've got a server authentication app which needs to accept many client 
>> connections, but also dispatch messages to a master server. Am I best 
>> using unconnected UDP? 
>>     
>
> You are *best* using TCP. Very few applications are actually suited to
> UDP. UDP:
>
>  * has no connection state
>  * has no flow control
>  * is unfriendly to networks (really the same as the previous point)
>  * has no keepalives
>  * has problems with MTU and fragmentation for messages > ~1400 bytes
>  * is subject to trivial spoofing
>  * has no message sequencing
>  * is hard to run crypto over (SSL over TCP == trivial)
>
> ...and so on.
>
>   
>> do i then have to deal with each received 
>> datagram by checking which host is has come from and acting accordingly?
>>     
>
> Twisted's UDP support is all "unconnected". All DatagramProtocol
> instances get a call to:
>
>  def datagramReceived(self, data, addr)
>
> ...where "addr=(ip,port)" for IPv4
>
> Similarly, you would do:
>
>   self.transport.write(bytes, addr)
>
> So, unconnected UDP is your *only* option, because that's how Twisted
> does it.
>
> However, so-called "connected" UDP is really just a way of saving the
> destination address on the socket. There's no *actual* connection
> involved.
>
>   
>> thanks
>>
>> Simon
>>
>> _______________________________________________
>> Twisted-Python mailing list
>> Twisted-Python at twistedmatrix.com
>> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
>>     
>
>
> _______________________________________________
> Twisted-Python mailing list
> Twisted-Python at twistedmatrix.com
> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
>
>
>