https://app.knowbase.one/vault/rfc/docid/7945
RFC7316: The Session Initiation Protocol (SIP) P-Private-Network-Indication Private Header (P-Header)
Internet Engineering Task Force (IETF) J. van Elburg Request for Comments: 7316 Detecon International Gmbh Category: Informational K. Drage ISSN: 2070-1721 Alcatel-Lucent ...