2CAN won't play nice with DAP-1522

[mikeh2338]

Struggling with a very strange issue: 2CAN is configured as the documentation describes (IP=10.xx.yy.10) and is working fine when directly connected to a laptop - we run the 2CAN utility and web interface which shows the Jag voltage and temperature.

Then we plugged the 2CAN and laptop into adjacent wired ports of the DAP-1522 and communication stops... almost. The web interface fails to see the 2CAN. We can't even ping the 2CAN, but the trusty 2CAN firmware utility is still able to detect and reset the device.

So why would our DLINK be blocking UDP and ICMP to the one IP address? We can ping the CRIO (10.xx.yy.2) and DLINK (10.xx.yy.1), but not the 2CAN (10.xx.yy.10). We checked the DAP-1522 configuration for filters and found nothing. We tried changing the netmask of all devices from a Class-A to a Class-C network (255.0.0.0 to 255.255.255.0) - the same behavior persists, including the part where the 2CAN works fine when directly connected to the laptop. I feel like we lost a whole night on an issue that should not exist.

I went back to the "Getting Started..." document on the First site this morning and read that we should be using IPs above 10.xx.yy.10. Does anyone know why we would have issues working with ANY non-broadcast IP? The 2CAN doc recommends 10.xx.yy.2 for CRIO, 10.xx.yy.6 for ClassMate, and 10.xx.yy.10 for 2CAN - this is how we were configured last night.

Any suggestions would be welcomed.

Thanks,
Mike

[codedr]

The one thing I could think of is that the cable you used to directly connect the
2CAN directly to the laptop is a cross-over cable. When you use the same cable
connect to the bridge, it doesn't work anymore.

[mikeh2338]

Thanks, Dr. C... As bizarre as this problem was on Tuesday, it was even more vexing that it was gone on Wednesday. It wasn't very satisfying and I hope it doesn't repeat when the chips are down, but at least we didn't waste any more time on this one.

We tried xover and strait up cat5 cables when the issue was occurring - neither made any difference. 2CAN seems to be able to handle either type automatically.

Thanks again,
Mentor Mike
First Team 2338

[Mike Copioli]

Originally Posted by codedr

The one thing I could think of is that the cable you used to directly connect the
2CAN directly to the laptop is a cross-over cable. When you use the same cable
connect to the bridge, it doesn't work anymore.

Both 2CAN ports support auto MDIX, crossover is not needed.