[svn-commits] oej: branch group/sip_session_timers r88990 - /team/group/sip_session_timers/...

[SVN commits to the Digium repositories]

Author: oej
Date: Tue Nov  6 09:51:55 2007
New Revision: 88990

URL: http://svn.digium.com/view/asterisk?view=rev&rev=88990
Log:
Adding parts of the documentation from Raj Jain

Modified:
    team/group/sip_session_timers/channels/chan_sip.c

Modified: team/group/sip_session_timers/channels/chan_sip.c
URL: http://svn.digium.com/view/asterisk/team/group/sip_session_timers/channels/chan_sip.c?view=diff&rev=88990&r1=88989&r2=88990
==============================================================================
--- team/group/sip_session_timers/channels/chan_sip.c (original)
+++ team/group/sip_session_timers/channels/chan_sip.c Tue Nov  6 09:51:55 2007
@@ -83,6 +83,46 @@
  */
 
 
+/*!  \page sip_session_timers SIP Session Timers in Asterisk Chan_sip
+
+	The SIP Session-Timers is an extension of the SIP protocol that allows end-points and proxies to
+	refresh a session periodically. The sessions are kept alive by sending a RE-INVITE or UPDATE
+	request at a negotiated interval. If a session refresh fails then all the entities that support Session-
+	Timers clear their internal session state. In addition, UAs generate a BYE request in order to clear
+	the state in the proxies and the remote UA (this is done for the benefit of SIP entities in the path
+	that do not support Session-Timers).
+
+	The Session-Timers can be configured on a system-wide, per-user, or per-peer basis. The peruser/
+	per-peer settings override the global settings. The following new parameters have been
+	added to the sip.conf file.
+		session-timers=["accept", "originate", "refuse"]
+		session-expires=[integer]
+		session-minse=[integer]
+		session-refresher=["uas", "uac"]
+
+	The session-timers parameter in sip.conf defines the mode of operation of SIP session-timers feature in
+	Asterisk. The Asterisk can be configured in one of the following three modes:
+
+	1. Accept :: In the "accept" mode, the Asterisk server honors session-timers requests
+		made by remote end-points. A remote end-point can request Asterisk to engage
+		session-timers by either sending it an INVITE request with a "Supported: timer"
+		header in it or by responding to Asterisk's INVITE with a 200 OK that contains
+		Session-Expires: header in it. In this mode, the Asterisk server does not 
+		request session-timers from remote end-points. This is the default mode.
+	2. Originate :: In the "originate" mode, the Asterisk server requests the remote 
+		end-points to activate session-timers in addition to honoring such requests
+		made by the remote end-pints. In order to get as much protection as possible
+		against hanging SIP channels due to network or end-point failures, Asterisk
+		resends periodic re-INVITEs even if a remote end-point does not support
+		the session-timers feature.
+	3. Refuse :: In the "refuse" mode, Asterisk acts as if it does not support session-
+		timers for inbound or outbound requests. If a remote end-point requests
+		session-timers in a dialog, then Asterisk ignores that request unless it's
+		noted as a requirement (Require: header), in which case the INVITE is 
+		rejected with a 420 Bad Extension response.
+
+*/
+
 #include "asterisk.h"
 
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
@@ -382,7 +422,7 @@
 		/* fatal - no chance to proceed */
 };
 
-/*! \brief Modes in which Astreisk can be configured to run SIP Session-Timers */
+/*! \brief Modes in which Asterisk can be configured to run SIP Session-Timers */
 enum st_mode {
         SESSION_TIMER_MODE_ACCEPT,      /*!< Honor inbound Session-Timer requests */
         SESSION_TIMER_MODE_ORIGINATE,   /*!< Originate outbound and honor inbound requests */