What is the NDI Discovery Server?  

The NDI discovery service is designed to allow you to replace the automatic discovery NDI uses with a server that operates as a centralized registry of NDI sources. 

This can be very helpful for installations where you wish to avoid having significant mDNS traffic for a large number of sources, or in which multicast is not possible2 or desirable. When using the discovery server, NDI is able to operate entirely in unicast mode and thus in almost any installation. 

The discovery server supports all NDI functionality including NDI groups 

Using a discovery server is as simple as running the application in Bin\Utilities\x64\NDI Discovery Service.exe. This application will then run a server on your local machine that accepts incoming connections with senders, finders, and receivers, and coordinates amongst them all to ensure they are all visible to each other.