{"draft":"draft-ietf-sip-outbound-20","doc_id":"RFC5626","title":"Managing Client-Initiated Connections in the Session Initiation Protocol (SIP)","authors":["C. Jennings, Ed.","R. Mahy, Ed.","F. Audet, Ed."],"format":["ASCII","HTML"],"page_count":"50","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"Session Initiation Protocol","abstract":"The Session Initiation Protocol (SIP) allows proxy servers to\r\ninitiate TCP connections or to send asynchronous UDP datagrams to\r\nUser Agents in order to deliver requests.  However, in a large number\r\nof real deployments, many practical considerations, such as the\r\nexistence of firewalls and Network Address Translators (NATs) or the\r\nuse of TLS with server-provided certificates, prevent servers from\r\nconnecting to User Agents in this way.  This specification defines\r\nbehaviors for User Agents, registrars, and proxy servers that allow\r\nrequests to be delivered on existing connections established by the\r\nUser Agent.  It also defines keep-alive behaviors needed to keep NAT\r\nbindings open and specifies the usage of multiple connections from\r\nthe User Agent to its registrar.  [STANDARDS-TRACK]","pub_date":"October 2009","keywords":["[--------]"],"obsoletes":[],"obsoleted_by":[],"updates":["RFC3261","RFC3327"],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC5626","errata_url":null}