1. A method for establishing communications with unknown end devices in a building automation system (BAS) based upon metadata descriptors provided by known and unknown end devices, the method comprising the steps of: discovering an unknown end device on a communication network utilizing a first communication protocol, the unknown end device associated with at least one of a point, a space, a system, or a subsystem for at least a portion of a building or campus, wherein discovering includes requesting the vendor data and product data from the unknown end device; querying the unknown end device for a HVAC communication protocol metadata descriptor; classifying the unknown end device as a self-describing end device if the unknown end device provides a HVAC communication protocol metadata descriptor in response to the query and selecting a second communication protocol that corresponds to the HVAC communication protocol metadata descriptor for the unknown end device; and classifying the unknown end device as a non-self-describing end device if the unknown end device does not provide a HVAC communication protocol metadata descriptor in response to the query, comparing the non-self-describing end device to known end devices of the BAS for at least one similar characteristic.