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Status:

PROPOSED STANDARD

Updates:

RFC 3261,RFC 3327

Authors:

C. Jennings, Ed.
R. Mahy, Ed.
F. Audet, Ed.

Stream:

IETF

Source:

sip (rai)

Cite this RFC:TXT  | XML  |  BibTeX

DOI:  https://doi.org/10.17487/RFC5626

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Other actions:Submit Errata  | Find IPR Disclosures from the IETF  | View History of RFC 5626

Abstract

The Session Initiation Protocol (SIP) allows proxy servers toinitiate TCP connections or to send asynchronous UDP datagrams toUser Agents in order to deliver requests. However, in a large numberof real deployments, many practical considerations, such as theexistence of firewalls and Network Address Translators (NATs) or theuse of TLS with server-provided certificates, prevent servers fromconnecting to User Agents in this way. This specification definesbehaviors for User Agents, registrars, and proxy servers that allowrequests to be delivered on existing connections established by theUser Agent. It also defines keep-alive behaviors needed to keep NATbindings open and specifies the usage of multiple connections fromthe User Agent to its registrar. [STANDARDS-TRACK]

For the definition ofStatus,seeRFC 2026.

For the definition ofStream, seeRFC 8729.