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Wireless bridge with multiple hosts

Discussion in 'Networking' started by Gorp, Nov 19, 2018.

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  1. Gorp

    Gorp Thread Starter

    Joined:
    Nov 19, 2018
    Messages:
    2
    First Name:
    Tom
    Greetings,

    I have some issues creating a stable connection between a mobile device (AGV) and a VM running a windows server OS (I would have to ask which version).
    The wireless network, VM and main gateway are present and not something I can see the settings of.

    The AGV is a vehicle able to freely drive around in a set area, it uses a number of ethernet devices to operate:
    - Navigation controller, this is an VBox IPC running unix. It is the main controller of the AGV.
    - IO controller, this is an Omron PLC, it is mostly intended to handle safety and status.
    - Laser scanners, 2 laser scanners measure the environment for navigation and safety purposes.
    - Wireless bridge, a HP Aruba 501 connects to an existing wifi for all communication.

    The wifi has multiple APs that the bridge can connect to and it allows for roaming. the VM that the AGV needs to communicate with is on the same subnet as the AGV.
    From time to time the connection seems ok, but it can drop at any moment and stay off for a seemingly random time. This is not a roaming effect as it can occur when stationary with a good connection to the network.

    Network setup:
    Code:
    Server (virtual machine)
    IP = 192.168.75.1
    GW = 192.168.75.254
     |
     \/
     Gateway (cisco, unknown type)
     IP = 192.168.75.254
     |
     ---------------------------
     |            |             |
     \/           \/            \/
     AP = ?       AP = ?        AP = ?
     |                          |
     \/                         \/
     Bridge                     laptop (service)
     IP = 192.168.75.31         IP = 192.168.75.6
     GW = 192.168.75.254        GW = 192.168.75.254
     |
     \/
     Moxxa (EDS-208)
     |
     -----------------------------------------------
     |                      |                      |
     \/                     \/                     \/
     VBox (Texim IPC)       PLC (Omron NX1)        2x Laser scanner (OS32C)
     IP = 192.168.75.32     IP = 192.168.75.33     IP = 192.168.75.34 & 35
     GW = 192.168.75.254    GW = 192.168.75.254    GW = 192.168.75.254
    
    When pinging the AGV components from the server or service laptop only 1 device tends to respond. pinging another device long enough and you can often get a connection to the other device.

    Similar setups have been created and they work but for some reason here it does not. what would be required to be able to access all network components at any moment? We test these devices with a setup where there are no seperate APs, the gateway is a router with wireless capabilities and then this works properly as well.

    Without a good clue what is causing this odd behavior I cannot propose changes to either the bridge or gateway settings. Even a nudge in the right direction may be enough to help.

    I do not have all the information, but I will answer any questions regarding more specific settings and/or devices if I can.
     
  2. TerryNet

    TerryNet Moderator

    Joined:
    Mar 23, 2005
    Messages:
    79,622
    First Name:
    Terry
    Let's see if I'm understanding the problem(s) ...

    Problem 1: Either the devices lose connection to the wireless bridge (WB) or the WB loses connection to the wireless network. I assume that it is not the former, and besides you've probably confirmed that it is the latter by pinging the WB.

    You haven't said whether the wireless network is using a business grade of coordinated APs or a bunch of "random" APs. Certainly with the latter, and maybe with the former, a Windows computer will periodically and seemingly randomly lose connection to the network and switch from one AP to another (often one with a weaker signal). Maybe the WB operates the same way (I have no idea).

    Problem 2: Sometimes one device communicates with the server but others do not. I don't really have an idea about this, but remember that Wi-Fi is half-duplex and only one device "talking" at a time. So, theoretically one device could hog the bandwidth for some period of time.
     
  3. Gorp

    Gorp Thread Starter

    Joined:
    Nov 19, 2018
    Messages:
    2
    First Name:
    Tom
    I also do not know whether they use industrial APs or random ones, my guess is industrial as they mentioned they just added an additional SSID rather than dedicated APs.
    I am familiar with the usual pause that you get from time to time, it may be related.

    None of the devices talk enough with anything else (even when monitoring) to fully hog the bandwidth. if this were the case it would not be possible at another location with the same hardware in the vehicle.
     
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