Introduction to Networking session

Hi everyone,

After watching the number of questions and issues related to network communications between the RoboRIO, drivers station, AP, USB, development laptops, and more, I was thinking about putting together a presentation that is basically “Networking 101”. It could cover things like:

  • History of the internet
  • Networking Architectures
    • logical - ring/mesh/star
    • physical - ethernet - thicknet/thinnet/twisted pair/wireless
    • OSI model
  • What is a bridge, router, wireless channel
  • Understanding IP addressing and subnetting
  • Understanding DHCP/DNS/mDNS
  • FRC-specific typical problems and solutions like:
    • why can’t I ping roborio-<team number>-frc.local?
    • I can connect to the radio but not the robot
    • what IP addresses do I use?

That’s my first attempt at an agenda and I’m more than happy to tweak it. I was also thinking about trying to fit it into a 50-minute timeframe to present it at a FRC Championship, but I don’t have enough time to get it done for 2016. I also think 50 minutes would be about the right length - it’s easy to turn your brain into mush with too much of this stuff at once. I just hope 50 minutes would be enough - I’m sure there would be questions.

I think this could help teams understand what’s happening in their team environment, and people might end up with a little more knowledge about how networking works.

Any thoughts? What would you like to see in an Intro to Networking session?

I love the idea. I still remember, “back in the day”, when the two PCs in my house were standalone and they were easy to understand. Then I learned how to install a 10Base2 network, and it all got more and more complex from there…

Today’s society is very familiar with the internet and the top few layers of the OSI model. Most people intuitively understand IP networks from the end-user perspective: I have a device that wants internet access, and I’ll connect to a router/AP at home or at school/hotel/Starbucks. They will give me an IP address. Now I can surf.

So when you tell people the FRC robot has a wireless radio and you connect a driver station laptop to that wireless SSID, there’s an intuitive understanding of how that works. Where it starts to get fuzzy is where the “FRC model” differs from the typical “consumer of internet services” model. And that’s where I would start delving into the content you’ve proposed, e.g. routers vs APs, IP addresses, subnets, static vs DHCP, etc.

From an FRC point of view, here are a few questions/pitfalls that I’ve seen come up frequently, at least on my own team:

  • why can’t I connect to the roborio?
  • how do I work with two roborios simultaneously? (comp bot and practice bot - in our case we set up two, completely separate SSIDs but both identically configured)
  • I flashed my radio to the competition firmware and now nothing connects
  • can I be connected to my robot network and the internet at the same time?
  • can I use any old router for my practice/test robot?
  • I’m getting a lot of wireless interference/disconnections
  • how does FMS work, bandwidth limitations on FMS - does setting up devices behind a Gigabit switch on-board the robot mean those devices on the switch can talk amongst themselves without worrying about bandwidth limits?

Fancy meeting you here…

Anyway, as a CSA for a multitude of events each year, I absolutely love this idea! Let me know if you want a hand with material.

I would definitely be interested in a presentation like that.

Though it might not be in the scope of what you are planning, I think expanding the “FRC-specific typical problems and solutions” would interest a lot of teams. Things like “why can I no longer connect to the robot over Ethernet?” or “Why can I connect over Ethernet, but not USB?” would be particularly helpful. I’m interested in the details you listed above, but general troubleshooting info might pull more people in.

Yes, I too would be interested in this.

Thanks for all the feedback!

I would love to spend the majority of the time on FRC-related networking issues. I think everyone needs to have a baseline of networking knowledge to understand what is going on. People shouldn’t have to be network gurus to make their FRC gear work correctly.

During the day I masquerade as a Systems Engineer at Cisco (or, maybe I masquerade as a mentor at night!). I have plenty of resources to put together the networking slides. Ideas and issues for FRC-specific networking are welcome. Keep them coming!

I wonder if this should really be 2 sessions - one is Networking 101 and the other is FRC Networking… that way there would be plenty of time for questions/white boarding/whatever. I know there are other Cisco employees that are mentors for teams. I’m sure some would be interested in presenting something like this to their local teams.

Thanks again everyone!

Maybe also hit on wireless alternatives for in pit/game scouting like Bluetooth etc. Things that are legal and don’t mess with field operations.


…and very interested.

I do lots of networking with my residential and commercial automation; but, really knowing how all the FRC FMS Network stuff works, still sometimes gets away from me, even after 1.5 years as the Programming Mentor.

  • Rob

Awesome idea!