Wireless Networking Problems

[2611.Sparky]

We're having problems with our wireless networking. The classmate looses communication with the robot after aproximently 25 seconds. We have double checked all the settings. The bridge ip:10.26.11.1, the router ip:10.26.11.4, the classmate ip:10.26.11.5, the robot ip is automatically set by the crio imager to 10.26.11.2, and the security is set to wpa-personal, Cypher type is AES, and the passphrase is 2611WPAKEY for both the router and the wireless bridge. For troubleshooting purposes, I hooked up one laptop(10.26.11.6) to our router, and another laptop(10.26.11.7) to the bridge. I then started two command prompts on both computers and started an auto ping(ping /t 10.26.11.X) to both the router and bridge. When the laptop connected to the bridge pinged the bridge, there was 0% packet loss with an average time of 1ms. When the laptop connected to the router pinged the router, it produced the same effect. However, when the laptop connected to the router pinged the bridge, or the laptop connected to the bridge pinged the router, results were intermintant. Here are some of the results(not necessarily in order, this has been going on for several days):
1: Both laptops pinging the opposite device(router's laptop pinging bridge)(robot and classmate disconnected). There would be successful returns 37 times with an average of 2ms, then 7 timeout's. It would then start over.
2: The laptop connected to the router pinging the bridge(robot and classmate disconnected) returned 100% packet loss while the laptop connected to the bridge pinging the router returned 0% packet loss.
3: Both laptops pinging the opposite device both returned 0% packet loss. When robot connected to bridge w/o classmate attached, nothing changed. When classmate connected to router w/o robot connected, nothing changed. When both were attached, it started returning 100% packet loss.

[2611.Shooter]

It would be really great if we could get a response on this! thanks!

[Garten Haeska]

You have a major problem being that you only use the d link router with your classmate in "AP" mode. This year they are getting rid of the linkseys bridge and router.

[2611.Sparky]

I'm not following you.
We had the d-link in bridge mode the whole time.

[Alan Anderson]

Originally Posted by 2611.Sparky

I'm not following you.
We had the d-link in bridge mode the whole time.

As Garten said, that is your problem.

Do you have the How to Configure… documents? There should be no bridge in the system anywhere if you set things up as instructed. The D-Link DAP-1522 will be your wireless access point, and your Driver Station computer will connect to it wirelessly.

Don't use last year's router. Don't use last year's bridge. Use only this year's access point, installed on the robot.

[pilum40]

My team apparently "fried" our D-Link DAP-1522. Will we get dinged (bumped out during inspection) by having to purchase another not on the original KOP?

[Mark McLeod]

You can buy replacements and spares of everything in the KOP.
The D-Link just has to be the same model.

[2611.Sparky]

Thanks, that worked. It works without the router until we hook the camera up to the c-rio. When the camera is connected, the connection only lasts about 7 seconds. We've tried both straight through cables and cross-over cables. Both returned the same result.

[CeeCee McShane]

okay, so our d-link will not stay connected to let us load the program to the crio. it connects for approximately 20-25 seconds then we lose connection. any suggestions. we have followed all instructions.

[jtechau]

We tried wireless communication with the robot as per the FRC instructions last night for the first time. It worked for a short while, then stopped working. We eventually concluded that the apparent cause of problems was that the laptop's ethernet and wireless adapters were both set to the required 10.xx.xx.5 IP address - and even when one of the adapters (LAN or wireless) was disabled, this was apparently causing problems.

What eventually worked for us was to set the wireless adapter back to DHCP, and use the LAN adapter connected to the Linksys router, with the robot's DAP-1522 set to bridge mode. (Falling back to last year's known-good configuration.)

I disagree with those who claim that a router is the cause of problems. It should work that way - in fact, it has to work that way in the competition setup. It should work either way - connecting the DS through the router with the DAP-1522 set as bridge, or directly to the DAP-1522 set as AP.

We still want to use the recommended setup - DAP-1522 as the AP/router, with the laptop directly connecting to the robot. I'm still uncertain how the DS software manages network connections, though. It cannot set both/all network adapters to the same IP address. So how does it choose between the LAN adapter and the wireless adapter? Or do we have to manually set up the network configuration?

I've heard that the DS software has been improved this year in regards to IP configuration, specifically for Win7. We're still using XP on our development platform (with this year's DS, etc). Can anyone enlighten us as to how the DS manages IP configurations this year?

[Mark McLeod]

Originally Posted by jtechau

So how does it choose between the LAN adapter and the wireless adapter? Or do we have to manually set up the network configuration?

This year's Driver Station allows you to manually select the NIC used.
It's on the Setup tab.

Outside that, the DS will continue to reset the last NIC specified, so if you went and did another one by hand, then when you restarted the DS application you could end up with two set to the same IP address.

[Alan Anderson]

Originally Posted by jtechau

I disagree with those who claim that a router is the cause of problems.

It's not the router per se that is giving you grief. It's the fact that you disregarded the explicit setup instructions and ended up with a configuration that isn't anything like what teams are expected to be using for development. All that manual fiddling about without a script makes it easy to get something a little bit off.

If you want to use DHCP in order to avoid IP conflicts, you can tell the D-Link DAP to do that for you. It's just one checkbox. Once our networking came up and functioned properly (which it did immediately with no fuss when we followed the directions), we turned on DHCP and made a couple of tweaks to the configuration. Specifically, we made it so our programming laptop would always receive 10.0.45.6 as its address and we would be able to forward Dashboard information to it easily.

Can anyone enlighten us as to how the DS manages IP configurations this year?

It manages them quite well.

[Greg McKaskle]

I'll try to review how the DS manages IPs, but there are so many configurations, that it may be necessary for you to describe which NICs you are using and additional routers and such.

On startup, the DS uses its ini settings to identify one wired and one wireless NIC that it may be controlling. Unless a NIC is set to be manually controlled, the DS compares the current IP with the one computed from the team number. If they do not match, it will ADD the IP being computed. The computed NIC for wired and wireless differ in the last byte, 5 and 9 I believe.

The ADD behavior is new this year. If a NIC is set to DHCP and a new IP is added, the resulting NIC configuration has only one IP assigned. If the NIC was already manually assigned, the resulting configuration will have two NICs. This can be seen with ipconfig or using the Advanced button in the IPv4 properties dialog.

A few other points. If the Setup>>NIC button is used to change NIC, the computed IP is deleted from the old and added to the new. If the team number is changed, the old computed address is deleted from the NICs and the new is added.

The DS for last season SET the IP. This season it uses ADD and DELETE in the hopes that it would allow a computer to be used for FRC DS without being dedicated for it. Since DHCP is so common, in most cases, nothing is changed. If you are making manual IP assignments, but have not set the NIC to manual, you will wind up with multiple IPs assigned. At this point, I'm not sure whether add/delete was an improvement.

Greg McKaskle

[cgmv123]

Here's what worked for my team.

1. Follow the reset procedure in the How-to document. Don't connect the cRIO or the classmate to the Router yet.
   
2. Then, take a computer that's not the classmate and set it's IP address to 192.168.0.51
   
3. Connect that computer and only that computer to the Netgear router in AP mode via Ethernet cable. Open Internet Explorer (other browsers have issues), go to 192.168.0.50. You should get the router login page. Configure your Router as described in the How-to document.
   
4. Enable the wireless card on the classmate (Fn+F1 on the 2010 version) and connect to the network you created. You should be able to drive remotely. I didn't have to do this, but you may have to change your NIC in the DS software.

Access point mode is used for testing, while bridge mode is only used for competition.

Note: We had issues programming wirelessly from another computer, so we connected it via ethernet cable to the router. We didn't have any issues other than that and I'm not even sure why we went back to cable only.

[jtechau]

Thanks Mark and Greg for your explicit and helpful replies.

Originally Posted by Alan Anderson

It's not the router per se that is giving you grief. It's the fact that you disregarded the explicit setup instructions and ended up with a configuration that isn't anything like what teams are expected to be using for development. All that manual fiddling about without a script makes it easy to get something a little bit off.

I can only speak for my team, but we didn't "disregard" any instructions. When we explicitly followed the explicit instructions, it didn't work. (That is, we did everything the script said, and nothing it said not to. Unless it was listed in a document other than the Driver Station and Radio setup guides.) We therefore reverted to last year's configuration, which worked for us.

Thanks to explicit and helpful replies, I expect that we'll have no more problems.

We did have another motivation to try the "competition" setup. We had some concern whether our robot radio was functioning in bridge mode, as we saw some irregularities, and wanted to test it before competition.