https://app.knowbase.one/vault/rfc/docid/5996
RFC5509: Internet Assigned Numbers Authority (IANA) Registration of Instant Messaging and Presence DNS SRV RRs for the Session Initiation Protocol (SIP)
Network Working Group S. Loreto Request for Comments: 5509 Ericsson Category: Standards Track April 2009 Internet Assigned Numbers Authority (IANA) Registration ...