Patent ID: 8606861

Claim:
A method comprising steps of: generating a message in a protocol in which a message header includes a first field for data identifying a message sequence associated with the message and a second field for a tag associated with an identifier of a source or a recipient of the message; identifying data for the first field for the message and data for the second field for the message; determining a domain-wide unique identifier based at least in part on the data for the first field and the data for the second field; and when at least one of the first or second fields of the message header for the message is without data, including data in a third field of the message header comprising at least the domain-wide unique identifier, wherein: the message is a Session Initiation Protocol (SIP) message, the first field is a Call-ID field, the second field is a From Tag sub-field or a To Tag sub-field, and the domain-wide unique identifier comprises a combination of data for the first and second fields and a domain-wide unique value.