Multiple/connected/secure microprocessors feeding a server

[gregulator]

Been a little out of the loop for the past couple of years on the microprocessor market, but I am wondering what my options are for microprocessors that:

1) Connect to a main server
2) Have relatively secure communication
3) Scalable
4) Relatively cheap (meaning common interfaces/protocols)

Basically I want a bunch of processors (anywhere from 10 to 1000) aggregating data, and getting commands from the server and reporting back to the server. I pretty much envision this as 18F PICs with ethernet (maybe some proprietary protocol on top of TCP/IP), all plugged into switches. I suppose wireless is easier to setup physically, but security and the number of devices worries me. All devices will get wall power too so running cables isn't a problem. Is CAN bus worth looking at or anything else? USB would be device limited.. and a pain.

I know this is very vague, but any thoughts? Anything new on the microprocessor forefront, or any other chips you have had luck with? I generally like Microchip because they have always had great support and dev kits.

Thanks!

 

[uclabachelor]

1) Connect to a main server

Any mcu that has peripherals that support industry standard protocols can talk to a main server. You just need to use the protocol that isn't point-to-point. Most protocols have software stacks that are already developed by Microchip.

2) Have relatively secure communication

Use a wired connection. Implement encryption in the software.

3) Scalable

Don't use point-to-point protocols like RS-232. Beyond that, scalability is only limited by your software architecture and hardware resources.

4) Relatively cheap (meaning common interfaces/protocols)

There's cheap, easy, and fast. Pick two out of the three.

 

[EagleKeeper]

CanBus will be limited to about 200 points. Also, the more connections on that network; the more interference you will have.
CAN has a lot of communication overhead.

Ethernet will be more efficient. You can have a dedicated network or use the Internet.
As stated above, use of the Internet means you have to control security.

As an example; many traffic signal systems use the scenario that you are talking about.

A central server and a micro-controller setup at each intersection. The micro runs the signal pattern, collects data and sends it upstream for analysis.