Hey there,
I'm running into a little trouble changing PresentValues of data points while the device which is sending the WritePropertyRequest is also subscribed to Confirmed COV notifications of that data point.

This is the error my device receives:

com.serotonin.bacnet4j.exception.ErrorAPDUException: ErrorAPDU(choice=127, errorClass=Device, errorCode=Operational problem)
	at com.serotonin.bacnet4j.transport.Transport.send(Transport.java:202)
	at com.serotonin.bacnet4j.LocalDevice.send(LocalDevice.java:370)

I'm not exactly sure what choice=127 means, but for some reason the target device doesn't process the WriteProperty request. Oddly enough, WriteProperty requests which are quickly sent after the first actually are successful.
Also, when using the UnconfirmedCOV service, WriteProperty requests do not produce any errors, and properties are written without issues.

Could this be a bug?

Hey there,
I'm running into a little trouble changing PresentValues of data points while the device which is sending the WritePropertyRequest is also subscribed to Confirmed COV notifications of that data point.

This is the error my device receives:

com.serotonin.bacnet4j.exception.ErrorAPDUException: ErrorAPDU(choice=127, errorClass=Device, errorCode=Operational problem)
	at com.serotonin.bacnet4j.transport.Transport.send(Transport.java:202)
	at com.serotonin.bacnet4j.LocalDevice.send(LocalDevice.java:370)

I'm not exactly sure what choice=127 means, but for some reason the target device doesn't process the WriteProperty request. Oddly enough, WriteProperty requests which are quickly sent after the first actually are successful.
Also, when using the UnconfirmedCOV service, WriteProperty requests do not produce any errors, and properties are written without issues.

Could this be a bug?

Thanks, that's quite helpful.

Hm, that's bad.
So just to be clear, I would change the ports of all the IpNetwork objects (2068 and 2069 in my example given) to the same one and that's it, or do I need to configure that somewhere in the Linux system as well?
I did manage to configure multiple Microsoft Loopback adapters yesterday, but only after that did I find out that they can't communicate with each other...

You said you used the ip command to set up virtual interfaces. By the looks of it, that seems to be something different to the network interfaces I configured via the "network/interfaces" settings file (and ultimately the ifconfig command I think). I'm checking the man pages for it but I'm not sure what I'm looking at. Could you give me examples of how you set up your virtual interfaces?

I managed to set up an Ubuntu 14 VM with virtual network interfaces. That took me longer than I'd like to admit since I'm no Linux guy nor really just a guy of anything in particular for that matter...
Despite setting up those interfaces and configuring the LocalDevices in both the SlaveDeviceTest and DiscoveryTest classes, I still didn't manage to make them talk to each other. I'm guessing I might have a fundamentally flawed understanding of how to set up such simulation. Could you look over my configuration and tell me if I'm on the right track?

My interface configuration is as follows

auto eth0 
iface eth0 inet static 
    address 10.0.2.15 
    netmask 255.255.255.0 
    gateway 10.0.2.2 

auto eth0:2 
iface eth0:2 inet static 
    address 9.0.0.2 
    netmask 255.255.255.0 

auto eth0:3 
iface eth0:3 inet static 
    address 9.0.0.3 
    netmask 255.255.255.0

I then try to bind two LocalDevice objects to eth0:2 and eth0:3 (after starting them up with the ifup command):

// In SlaveDeviceTest.java
LocalDevice localDevice = new LocalDevice(1969, new Transport(new IpNetwork("9.0.0.255", 2068, "9.0.0.2")));

// In DiscoveryTest 
LocalDevice localDevice = new LocalDevice(1234, new Transport(new IpNetwork("9.0.0.255", 2069, "9.0.0.3")));

Now, my expectation was that when first starting SlaveDeviceTest and then DiscoveryTest, SlaveDeviceTest would receive the WhoIsRequest. But what actually happens, is nothing. What are my mistakes?

Thanks for your very swift response. I didn't manage to get a working multi-device setup working yet. For some reason, any Linux VM I set up, is slow as fck and I could only work with Windows for now. I tried using the Microsoft Loopback Adapter to set up another network interface, but so far couldn't use that for my second BACnet device. Do you have any idea by chance how to get it working under Windows? I will try to set up a VM tomorrow on my desktop machine at work.

Hi Scott,
I'm running into the same issue. Could you figure out how to run multiple local devices?
I installed BACnet4J today and am trying to run the sample tests with mediocre results. As you mentioned, the first device runs fine, but subsequent devices try to bind to the same localBindAddress in bacnet4j.npdu.ip.IpNetwork.

Additionally, I'm wondering about the WARNINGs as well. For instance, both my BacnetTest and DiscoveryTest classes spew out the "Another instance with my device instance ID found!" error. The device's MAC address magically changes between sending and receiving its own message. How come?

Best Regards.