there exists a protocol stack presented by EPCglobal
here[
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They described your need here:
Discovery, Configuration & Initialisation Standard for Reader Operations[
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If your reader is compliant with this protocol, then you can find some middleware libraries or applications which fulfill your needs. you should take a look at the documentation of your reader.
If not, it can be problematic to implement such a requirement. if your reader supports embedded application development, you can write an application to run on your reader and another application to achieve discovery by talking with that application running on the reader.
before diving into such things, I strongly recommend to search for existing solutions (possibly from your vendor)
another resource from microsoft:
BizTalk RFID[
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