pylon:
Also provide an overview of the network connections and all involved devices (Arduino Shield, switches/hubs, router, PCs, that video device, etc.).Did you check the cables.
Do I understand that correctly, you have several installations of the same type? Did you check that every MAC address in your network is unique?
yes i checked the cable i didn't check every mac i changed the mac of three arduinos so two of them the changes give results but the last one doesn't change