Balluff - BVS CA-GX0 / BVS CA-GX2 Technical Documentation
Discovering Devices In Different Subnets

What is Unicast Device Discovery?

With Unicast Device Discoveries it is possible to discover GigE Vision™ devices that reside in a different subnet than the host.

During the standard device discovery process the host sends a broadcast discovery packet into each subnet that the host itself is directly connected to via it's network interfaces. All GigE Vision™ devices receiving this discovery packet will send an acknowledge packet (DISCOVERY_ACK) back to the host.

In most cases this is sufficient to discover every GigE Vision™ devices as they are connected to host either directly or via switch to the host. Sometimes however the host does not reside within the same subnet as the GigE Vision™ device which makes it impossible to discover it via a broadcast packet as switches or routers typically don't forward these packets into other subnets.

Device discovery using only a broadcast discovery

In order to allow using devices residing in different subnets as well, so called "Unicast Discovery Packets" can be sent to a GigE Vision™ device in addition to the usual broadcast discovery packets. In order to do this the IPv4 address of the device to discover must be known upfront.

Device discovery using a broadcast discovery and an additional unicast

How it works

Please have a look at the "Set Up Device Discoveries In Different Subnets" chapter of the IPConfigure manual for a detailed description.