VNC over UDP

[mloiaco]

Is there any way to force VNC to use UDP instead of TCP?

[faali]

I am also looking for it???

[kissson]

would it be a speed burst ?

[B]

Possible, but I doubt it in practice.

I don't know if the RFB protocol knows or cares whether it's transmitted via TCP or UDP, but of course with UDP you'll need higher level software doing the error checking for missed and misordered packets.

I think screen display and remote control is a little less error-tolerant than normal UDP uses like streaming video and audio.

Then again, considering how dreadfully slow most VNC connections are, anything would help!

[Tangente]

Greetings. My team and I are implementing UDP transport in UltraVNC.
Our idea, is to bind the vncSockConnect (TCP) to 127.0.0.1 and spawn a parallel vncUdpSockConnect thread that listens UDP traffic. When a new udp client try to connect (he send a HELLO packet to notify his intention), our vncUdpSockConnect creates a new tcp socket and connect it to the server socket, then all udp traffic from this client will be retransmitted to tcp socket in loopback.
We'll submit a patch soon (i hope).

[B]

Sounds like a clever approach -- you're preserving the TCP path back to regular engine.

If you're going to be taking a while to do it, you might consider working with the new 2.x branch. There are a couple of developer discussions ongoing in the forum.

I guess the only part I don't understand is that, if this will require customizations at both client and server ends, as I assume it will, then why bother with the loopback approach, since UDP support could be handled directly within a new VNC?

Anyway... thanks for sharing!

[Tangente]

Mainly for multithread nature of Ultravnc: every client spawns a thread and to adapt it to udp will be difficult.

[JohnPeter]

I have been looking at inexpensive routers, such as ones that end-users might install in their residences and small businesses. While it is common for them to pass TCP/IP, UDP is almost never mentioned in the specs. I know UDP is a simpler protocol than TCP; perhaps accommodation for UDP is universally understood... i.e., implied; but I am not a student of these details.

It seems that UltraVNC RELIES on TCP/IP and not UDP. Attempts to exploit UDP might encounter an obstacle, if routers will not cooperate.

Can anyone tell me if UltraVNC is, firstly, natively NOT dependent on UDP?

Can anyone tell me if routers, by and large, pass UDP?

Thanks!

[Tangente]

UltraVnc and protocol RFB relies in TCP.
We are working to implement UDP as alternative. First choice will be always TCP.