Neustar, Inc. The Secure Telephone Identity Revisited (STIR) framework defines means of carrying its Persona Assertion Tokens (PASSporTs) either in- band, within the headers of a SIP request, or out-of-band, through a service that stores PASSporTs for retrieval by relying parties. This specification defines a way that the out-of-band conveyance of PASSporTs can be used to support large service providers, for cases in which in-band STIR conveyance is not universally available.