Remote Program Call Server
The Remote Program Call Server (RPC) is a server component that runs on every machine within the Presence Domain (with the exception of client-only machines).
It is responsible for launching executable files on demand, which is required under the following circumstances:
In a typical Windows installation the RPC will run as a Windows Service, named "Presence RPC Server". Since all it is responsible for launching the Presence Server and Database Server it is important to ensure that the RPC Server has the permissions required to access any files or resources that the Presence Server will need to access. For this reason it is often a good idea to create a Windows account that the service can run as.