[HECnet] UDP tunnelling over SSH - Solution for people dynamic IP addresses?

What I was referring to is the cascading time-out problems you can sometimes get tunnelling one TCP connection over another, e.g. HTTP over a PPP over SSH connection: 3. HTTP (TCP) 2. IP 1. PPP 0. SSH (TCP) Sometimes if a time-out occurs and layers 0 and 3 have different retransmission timers, the retransmissions kill the whole shebang. More details can be found at: http://sites.inka.de/~W1011/devel/tcp-tcp.html Not sure if this will be a problem with NSP over TCP however, but I can imagine it might be (if the NSP retransmission timer is faster than the underlying TCP timers). Sampsa On 13 May 2009, at 15:25, Paul Koning wrote: "Sampsa" == Sampsa Laine <sampsa at mac.com> writes: Sampsa> The main disadvantage I can see is that SSH runs over TCP so Sampsa> any dropped packets might cause more delays than using Sampsa> straight UDP. That isn't actually a disadvantage when you travel all the way to the top of the stack. Yes, the DECnet network layer (just like IP) uses, and provides, a datagram service. But it also uses retransmit internally for stuff that has to get through, and of course the transport layer (NSP) makes a reliable service through timeout and retry. So a tunnel over TCP is just fine. It means you have a lossless network (ignoring congestion in the DECnet nodes). So instead of having delays due to timeout and retransmit in NSP, you have the same delay (or, quite possibly, a shorter delay) due to timeout and retransmit in TCP. The overall application performance should come out essentially the same. paul