[asterisk-users] How do extensions "stay registered"

[Eric Wieling]

The SIP server has no way to tell the device is no longer available until the next time the device registers (or the server tries to send a call to the device).

ASTERISK has the qualify feature, which uses a SIP OPTIONS packet to probe the peer every min or so.  

-----Original Message-----
From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of eherr
Sent: Monday, November 14, 2011 5:19 PM
To: 'Asterisk Users Mailing List - Non-Commercial Discussion'
Subject: Re: [asterisk-users] How do extensions "stay registered"

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"

 

If I am not mistaken.

 

--E

 

From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Danny Nicholas
Sent: Monday, November 14, 2011 5:01 PM
To: 'Asterisk Users Mailing List - Non-Commercial Discussion'
Subject: Re: [asterisk-users] How do extensions "stay registered"

 

"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 at impalanetworks.com).

 

From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Douglas Mortensen
Sent: Monday, November 14, 2011 3:52 PM
To: 'asterisk-users at lists.digium.com'
Subject: [asterisk-users] How do extensions "stay registered"

 

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?

 

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.

 

But am I oversimplifying it? Is there more to the process?

 

Thanks,

-

Doug Mortensen

Network Consultant

Impala Networks Inc

CCNA, MCSA, Security+, A+

Linux+, Network+, Server+

.

www.impalanetworks.com

P: (505) 327-7300

F: (505) 327-7545

.