Questions regarding Python/TraCI Co-simulation and OMNeT++ 6.x Support

[xwh0625]

Dear MOSAIC Development Team,

I hope this email finds you well. I am currently using Eclipse MOSAIC for a project focused on vehicle-to-cloud collaborative traffic control and I have two questions about its capabilities.

1. Co-simulation with a Python script for traffic flow control:

My goal is to use an external Python script to dynamically manage the number of vehicles in the simulation. The script's logic is to maintain a constant number of vehicles by intelligently adding new ones to less congested areas, similar to the logic in the provided script. This script would connect to the SUMO instance managed by MOSAIC via TraCI.

However, I have encountered persistent connection issues. My Python script consistently fails to connect to the SUMO instance, receiving a ConnectionRefusedError: [WinError 10061].

We have tried a comprehensive set of configurations to enable this co-simulation, including:

Ensuring the SumoGuiAmbassador is used in runtime.json.

Setting "allowExternalConnections": true in the SUMO configuration.

Setting a fixed public port, e.g., "port": 8813.

Adding commandLineOptions to support multiple clients, specifically "--num-clients", "2".

Strictly following the execution order: starting MOSAIC first, waiting for the SUMO GUI to appear and run, and only then starting the Python script.

The final diagnostic test we performed was to run SUMO directly from the command line, completely separate from MOSAIC, using the same parameters (e.g., sumo-gui.exe -c your_config.sumocfg --remote-port 8813 --num-clients 2). This test also failed, suggesting that the version of SUMO in my environment may be incompatible with the --num-clients parameter.

Could you please advise on the officially recommended method for enabling an external Python/TraCI script to connect to and control a MOSAIC-managed SUMO instance? Is this a known issue, or is there a different configuration approach we should be taking?

2. Support for OMNeT++ 6.0.3+ and Simu5G:

My second question is about network simulation capabilities. I am very interested in integrating Simu5G into my scenario to simulate V2X communication over a 5G network. Simu5G requires OMNeT++ version 6.0.3 or newer.

Does the current MOSAIC OMNeT++ federate support these newer versions of OMNeT++ (6.0.3 and above)? If not, are there any plans for this support in a future release?

Thank you for your time and for developing this powerful tool. Any guidance you could provide on these two topics would be greatly appreciated.

Best regards,

[schwepmo]

Hey @xwh0625,
regarding your first question, this is generally possible. I did some very short tests and managed to add a vehicle from a separate traci client to the Barnim scenario. The required changes are committed here https://github.com/eclipse-mosaic/mosaic/compare/multiple-sumo-clients-tests.
It seems to be important that you call setOrder on all clients, which I just hacked into MOSAICs implementation of the traci client. Additionally, to set the SUMO port, you need to adjust the respective port in the runtime.json not in the sumo configuration, maybe this was the reason why it wasn't working. I'm using SUMO version 1.23.1.

Regarding the second question: As of now, MOSAIC doesn't support newer OMNeT++ versions. We of course are interested in supporting them and are also highly interested in 5G simulations. In fact, @hoelger is currently working with a student on upgrading Omnet, though I'm not sure how fast progress will be and what the desired versions are.
If you have the free time, feel free to give the upgrade a shot yourself and we'll help along the way.

Hope this helps!

[xwh0625]

Thank you again for your expert assistance. Your explanation of the multi-client architecture and the setOrder command was crucial. I'm pleased to say that I have now successfully implemented the Python traffic control in my scenario.

[hoelger]

Dear xwh0625,

We have an internal version supporting OMNeT 6.1 which will be merged as soon as we have the time to propperly review it. To be realistic I assume that this will be merged and available some time in August.

[hoelger]

For the integration of cell capabilites, please find the updated protocol in this branch: https://github.com/hoelger/mosaic/tree/1057-lte-in-ns3.36-integration

I assume that this will be merged to main in August, too.
So far this is only implemented for ns3.

[hoelger]

Thanks to the hard work of @Jacenty00 we now have a first version where omnet is able to support 5G cellular communication!

See branches here:
https://github.com/eclipse-mosaic/mosaic/tree/1132-enable-lte-5g-in-omnet
https://github.com/mosaic-addons/omnetpp-federate/tree/1132-enable-lte-5g-in-omnet