Auto-Discovering IoT Devices Using mDNS
DNS is a great tool for sites on the Internet. However, most local networks do not have dedicated DNS servers to resolve internal host names, presenting a roadblock when attempting to reach devices without resorting to IP addresses.
mDNS (Multicast DNS) fills this gap by utilizing the .local suffix.
Network nodes can send a multicast DNS request to a local domain. This inquiry will be received by all devices on the LAN supporting mDNS. Any device with a matching name will respond to the query, providing amongst other details, the currently configured local IP address.
As the reply is also sent via multicast, it automatically notifies all other nodes listening to mDNS updates.
After receiving the IP address of the desired destination, the original requestor can then communicate directly with the destination device. This relieves the user from having to memorize long lists of IP addresses.
RIO xR3 units support mDNS. This enables the RIO xR3 Front End application to offer auto-discovery, as the IP address of a unit does not have to be known prior to bringing up the unit for the first time:
To begin, simply launch the RIO xR3 front-end application. By default the Auto-Probe option will be enabled. The application then performs a quick scan of the local network to discover all available RIO xR3 units:
Click on the field Select a discovered device and pick one of the discovered units from the drop-down selection.
Alternatively, remove the check mark from the Auto-Probe option, then manually enter the IP address of the unit to be accessed.
Ralf Doewich
Optima Tele.com, Inc.