[Twisted-Python] UDP with multiple connections
Phil Mayers
p.mayers at imperial.ac.uk
Tue Oct 9 17:37:02 MDT 2007
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
More information about the Twisted-Python
mailing list