FAQ

ARA

  1. I am new to ARA, where and how can I get started?

    As a new user, explore the ARA webpage for a high-level information on ARA. For specifics on ARA testbed capabilities, visit the Current ARA Capabilities page. If you are ready to explore ARA, do not wait to register your user account and on confirming your registration, start with ARA Hello World experiment to get a first-level hands-on experience of ARA experiments workflow. Further, you can explore specific domains of wireless experiments such as AraRAN and AraHaul.

    For getting a glimpse of ARA vision, design, and implementation refer the following manuscripts:

ARA Portal

  1. Unable to ping/SSH to the container from ARA jumpbox

    Reason: The security group rules of your project is blocking the ICMP and SSH traffic.

    Solution: Go to the security groups page via Project -> Network -> Security Groups on the dashboard. Click on the Manage Rules button of the default security group. In the redirected page, you can see the existing security group rules. You need to add two rules with the following attributes:

    Rule 1

    • Rule: All ICMP

    • Description: Optional

    • Direction: Ingress

    • Remote: CIDR

    • CIDR: 0.0.0.0/0

    Rule 2

    • Rule: SSH

    • Description: Optional

    • Remote: CIDR

    • CIDR: 0.0.0.0/0

  2. Unable to create container

    Reason: The Docker daemon may face some issues while downloading the image from the Docker Hub due to any kind of network disruptions in the wireless management channel. This error may occur at UE sites deployed at remote locations. The status of container may show as Error.

    Solution: Delete the existing container and create a new container. Note that the container with error will be deleted automatically on an error.

AraRAN

  1. Permission denied while running gNB or UE

    Reason: The Docker container does not have permission to access the SDR.

    Solution: Stop (no need to delete the container) the respective container from the Project -> Containers page and start the container again. In case, restarting the container does not help, you can delete and create the container again.

  2. Crash/core dump in the nr-softmodem command

    Solution: Re-run the nr-softmodem command. It may happen that you may need to run the command 2-3 times.

  3. UE not getting ``oaitun_ue1`` interface

    Reason: The PDU session may have not yet been established between UE and the 5G core network.

    Solution: Restart the 5G core network but running the following command in the core network container.

    # docker compose down
# docker compose up -d

  4. UE not connecting to gNB

    Reason: When the UE starts, it searches for the signals from the BS and begins a procedure to attach. The procedure takes a few seconds, especially when the UE is far away from the BS.

    Solution: In case the UE is not getting connected to the gNB after executing the command nr-softmodem (Step 12 of Experiment 6 of AraRAN experiments) for 30 seconds, we suggest to stop the command (using Ctrl+C) and run it again. It may happen that you need to run a few times to get the UE connected to the BS.

  5. Skylark Key Error during Measurements

    Reason: AraMIMO measurements scripts runs into Key Error issue when collecting data. The Skylark application does not return the control from the call to the data through the object client and the script keeps listening for return data.

    Solution: Stop the script with CTRL + C and rerun the script. If it keeps running into this issue, reduce the number of iterations e.g. 10 or 15 or 30.

AraHaul

  1. iPerf Server Inconsistency Error during Measurements

    Reason: At times the unstable link results in packet loss, which makes the iPerf control channel inconsistent. In such cases, the server side produces the continuous output as shown below.

    ../_images/Optical_iperf_Server_Error.png

    Solution: Stop the server with CTRL + C and restart the server using the following command.

    # iperf3 -s

  2. Bad File Descriptor

    Reason: Due to unstable link between the client and server, iPerf may not be able to establish the connection and produces the following error.

    ../_images/Bad_File_Descriptor_iperf.png

    Solution: Restart the iPerf server and client.