The internet of things (IoT) is kind of the current discussion in many publications. The idea behind the internet of things is that everything will be connected to the internet, allowing monitoring and control of those things. As things are going, it is still too expensive to connect everything to the internet, and there many implications of connecting everything to the internet.
Many aircraft are getting WiFi in the cabin, people think the next step is putting an iPad in the cockpit, and connecting to the cabin WiFi and that should do it. Get all the flight plans, updates, weather and other data from headquarters we are all done. The trouble is, and was pointed out in the first post of this blog, there are security thoughts that need to be considered.
On transport aircraft, most of the cockpit is connected. Well connected, in that the FMS talks to the airopilot, and the EFIS may talk to the ACARS system, and the radios share a common bus. The trouble is, the cockpit is not talking IP, so it isn't easy to connect it to the WiFi, and it probably isn't a good idea.
In your GA business jet, it might be OK to connect the cabin to the cockpit. The people in the aircraft are usually well vetted, and may actually own it. They have a serious reason to be riding in the aircraft to the destination. Smaller aircraft may not have the means to get WiFi to the ground, but WiFi or other Ethernet connections could actually be done allowing the GPS to talk to the ADS-B transciever, and the MFD in the panel.
Allowing the cabin WiFi be connected to the cockpit of a part 121 transport aircraft is probably a bad idea. Probably the biggest problem would be if the aircraft were in a place with weak connection to the ground, and bandwidth was limited, who would get priority, the passenger watching Netflix or the cockpit needing a new route around some weather. The marketing department might argue the passengers, but flight operations department might argue the cockpit should have priority.
The other reason connecting the cockpit to the cabin using WiFi is a bad idea would be straight up security. There would be 100 people in the back bored wondering what is going on in the flight. It may be a curiosity for some, or a goal for others, they may just want to look at things, and manage to get access to say the current flight plan, in the FMS, and accidentally adjust it. Sure there could be firewalls and whitelists and other techniques to keep only the cockpit in the cockpit network, but there are ways for others to get in.
Having a separate cockpit connection to the ground is probably the right answer to the security question. having an isolated cockpit will make it harder to keep the cabin people out of the cockpit network. It will be important to consider all the connections to the cockpit, and how secure they may be. If there is only an unsecured connection to the cockpit, then the cabin can probably still get to it through some ground station. Worse, if the cockpit doesn't have a secure connection to the ground, now there may be thousands of bored people trying to see what is going on in the aircraft.
Security has to be the first thought when building cockpit connected interfaces. Security through obscurity isn't real security, so proprietary standards won't be a long term solution. Bored people look at proprietary standards as a new challenge, and eventually they get figured out. Using industry best practices will be the only way to insure interoperability along with proper security.
It may be that the aircraft cockpits are only connected using one vendor (IE ARINC as things are today), where they provide an isolated network that only they can get to the aircraft. The messages will have to pass though a filter, and have proper originator white lists. All messages would be encrypted such that only known originators and destinations can see and use the messages. Certainly ARINC can't let Southwest Airlines read Delta Airlines messages, as well as some random person on the ground should not be able to sent messages to any aircraft.
It will take a bit of time for things to shake out, but eventually the cockpits will be connected.