CIDIN, X25 and COTS technology
 

OK, so in Europe we're apparently using AFTN and CIDIN. Where does X25 fit into this? And why are we not using TCP/IP and the internet to transmit messages as a successor to the AFTN?

Wrong forum?
 

WXM,

Suggest you repost this on the Computers and Internet forum. Mention TCP/IP to any pilot and his eyes will roll back into his head. Unless you're Danny. Or one of the other ModBods. :D

Nial

Disclaimer: Above implied insult to pilots' computing ability is meant as a joke, nothing else!

I think I can answer the second part of of this one, having recently spent time working on a bid to a certain governmental organisation dealing with aviation to replace their data network. Similar thing to AFTN, in that flight-safety critical data was intended to go over it.

TCP/IP and the internet ARE NOT RELIABLE enough. The network design proposed was ultra-reliable, in that it had multiple paths in case of failure, and the fall-back paths were of different technologies. Yes, the X25 network traffic was encapsulated in TCP, but then prioritised to ensure it reached its destination ahead of other traffic. This guarantees data delivery. Can't do that on the internet.

Ahh, but you can do QoS with certain routers where you can prioritise certain TCP packet types.

Ah ha. Many thanks. I see clearly now why the Internet is not used! Bit of a silly question come to think of it.

WDTBD :

I think I know what you mean, but if you don't control all the routers in the path, then there's no guarantee of QoS. These people will control all the routers in the path, which is something they MUST have to ensure the transport of the flight-safety critical data.

Nr - out of interest, what does an X.25 network do that a TCP/IP network cannot? Is it synchronicity related? There is a lot of software around that does assured delivery over unreliable networks (i.e. TCP/IP or CDPD), so that aspect isn't actually a problem..? I know of people running million-dollar transactions from a Nokia 9210, so it can be done very well :)