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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>I think the question is more along the lines of how does asterisk know immediately when a sip phone becomes on line and when you unplug the phone from the network, how does asterisk essentially know immediately that it status is “UNKNOWN”<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>If I am not mistaken.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>--E<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-bounces@lists.digium.com] <b>On Behalf Of </b>Danny Nicholas<br><b>Sent:</b> Monday, November 14, 2011 5:01 PM<br><b>To:</b> 'Asterisk Users Mailing List - Non-Commercial Discussion'<br><b>Subject:</b> Re: [asterisk-users] How do extensions "stay registered"<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='color:#1F497D'>“Extensions” do not register – peers do. A peer can register itself or be registered by Asterisk. In most cases the “extension” is equivalent to the “peer” (301 = 301) but it can be quite different (301 = sipuser1) or (301 = doug@impalanetworks.com).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-bounces@lists.digium.com] <b>On Behalf Of </b>Douglas Mortensen<br><b>Sent:</b> Monday, November 14, 2011 3:52 PM<br><b>To:</b> 'asterisk-users@lists.digium.com'<br><b>Subject:</b> [asterisk-users] How do extensions "stay registered"<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I know this is probably a very basic question for many on this list. But in troubleshooting an issue, I wanted to take a step back & ask the question. In Asterisk (or maybe all SIP), how do extensions stay registered with the SIP server?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Do the extensions simply register repeatedly as a means of telling asterisk “I’m still here”, or are there actual keepalive packets that are transmitted to actually keep a TCP session alive? My guess is the former.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>But am I oversimplifying it? Is there more to the process?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>-<o:p></o:p></p><p class=MsoNormal><span style='font-size:14.0pt'>Doug Mortensen<o:p></o:p></span></p><p class=MsoNormal>Network Consultant<o:p></o:p></p><p class=MsoNormal><b>Impala Networks Inc<o:p></o:p></b></p><p class=MsoNormal><span style='font-size:10.0pt'>CCNA, MCSA, Security+, A+<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt'>Linux+, Network+, Server+<o:p></o:p></span></p><p class=MsoNormal>.<o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt'><a href="http://www.impalanetworks.com">www.impalanetworks.com</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt'>P: (505) 327-7300<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt'>F: (505) 327-7545<o:p></o:p></span></p><p class=MsoNormal>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>