I support these changes. In fact, just had a big issue with a major carrier because of the "require Timer" feature. Please remove it from the INVITE when the timer fires.<div>F.Alves<br><br><div class="gmail_quote">
On Thu, Aug 26, 2010 at 3:06 PM, David Vossel <span dir="ltr"><<a href="mailto:dvossel@digium.com">dvossel@digium.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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</div><a href="https://reviewboard.asterisk.org/r/879/" target="_blank">https://reviewboard.asterisk.org/r/879/</a><br>
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Review request for Asterisk Developers.<br>
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<br>
</div>Summary<br>
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This is a simple patch. This review is more to verify my expectations of how Session Timers are supposed to work are sane.<br>
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CHANGES:<br>
1. Never put "timer" in "Require" header. This is not to our benefit and RFC 4028 section 7.1 even warns against it. It is possible for one endpoint to perform session-timer refreshes while the other endpoint does not support them. If in this case the end point performing the refreshing puts "timer" in the Require field during a refresh, the dialog will likely get terminated by the other end.<br>
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2. Change the behavior of 'session-timer=accept' in sip.conf (which is the default behavior of Asterisk with no session timer configuration specified) to only run session-timers as result of an incoming INVITE request if the INVITE contains an "Session-Expires" header... Asterisk is currently treating having the "timer" option in the "Supported" header as a request for session timers by the UAC. I do not agree with this. Session timers should only be negotiated in "accept" mode when the incoming INVITE supplies a "Session-Expires" header, otherwise RFC 4028 says we should treat a request containing no "Session-Expires" header as a session with no expiration.<br>
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Below I have outlined some situations and what I would Asterisk's behavior to be. The table reflects the behavior changes implemented by this patch.<br>
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SITUATIONS:<br>
-Asterisk as UAS<br>
1. Incoming INVITE: NO "Session-Expires"<br>
2. Incoming INVITE: HAS "Session-Expires"<br>
<br>
-Asterisk as UAC<br>
3. Outgoing INVITE: NO "Session-Expires". 200 Ok Response HAS "Session-Expires" header<br>
4. Outgoing INVITE: NO "Session-Expires". 200 Ok Response NO "Session-Expires" header<br>
5. Outgoing INVITE: HAS "Session-Expires".<br>
<br>
Active - Asterisk will have an active refresh timer regardless if the other endpoint does.<br>
Inactive - Asterisk does not have an active refresh timer regardless if the other endpoint does.<br>
XXXXXXX - Not possible for mode.<br>
______________________________________<br>
|SITUATIONS | 'session-timer' MODES |<br>
|___________|________________________|<br>
| | originate | accept |<br>
|-----------|------------|-----------|<br>
|1. | Active | Inactive |<br>
|2. | Active | Active |<br>
|3. | XXXXXXXX | Active |<br>
|4. | XXXXXXXX | Inactive |<br>
|5. | Active | XXXXXXXX |<br>
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<br>
This addresses bug 17005.<br>
<a href="https://issues.asterisk.org/view.php?id=17005" target="_blank">https://issues.asterisk.org/view.php?id=17005</a><br>
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Diffs<br>
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/branches/1.8/channels/chan_sip.c 283768<br>
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Diff: <a href="https://reviewboard.asterisk.org/r/879/diff" target="_blank">https://reviewboard.asterisk.org/r/879/diff</a><br>
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<br>
Testing<br>
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Thanks,<br>
<br>
David<br>
<br>
<br>
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