[asterisk-users] Subscription-State always active ?

Joshua Colp jcolp at digium.com
Thu Jul 31 08:06:45 CDT 2014

Jonas Kellens wrote:
> On 31-07-14 14:28, Joshua Colp wrote:
>> Jonas Kellens wrote:
>>> Hello,
>>> I read on Yealink support that Yealink IP-phones expect
>>> "Subscription-State:terminated" for there Presence/BLF-functionality.
>>> So how can I get "Subscription-State:terminated" on Asterisk ?
>> That would be a bit strange as the subscription would then be
>> terminated, no more NOTIFY messages would go to it which would defeat
>> the purpose of subscribing to something. The only way to achieve that
>> would be to have the phone unsubscribe or to change the code to force
>> it to terminate the subscription under certain circumstances. This
>> would require knowing the exact specifications and details of what
>> they expect and when. Is there currently a problem you are facing with
>> subscription support?
> Hello,
> this "Subscription-State:terminated" is expected when the IP-phone goes
> offline (Unregister or cut off from power).

I would expect that if the phone that went offline was subscribed to 
stuff and the subscription expired.

> At that moment indeed the IP-phone no longer sends NOTIFY messages.
> Also, Asterisk knows very well the SIP peer becomes unreachable (see my
> first post). But still Asterisk replies "Subscription-State: active" to
> the IP-phones that request the state of the offline SIP peer.

Generally IP phones don't send NOTIFY messages. They are sent NOTIFY 
messages to inform them of the state of things they have subscribed to 
(such as devices or mailboxes).

> Yealink expects "Subscription-State:terminated" so the Yealink IP-phone
> can put out the BLF light (in stead of staying in a green mode, which
> indicates that the SIP peer is still online but not in a call).

Sending Subscription-State:terminated terminates the subscription. If 
the device in question comes back online you can't send any new NOTIFY 
messages because the subscription is gone. The state of what you are 
subscribed to and the underlying state of the subscription itself are 
different things.

> So I can follow the Yealink logic. Can you ?

Not really as it doesn't make sense to me. Do you have a link to the 
documentation for this?

I've also done a search on the issue tracker and there have been no 
issues filed ever about subscriptions and specifically Yealink.

Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

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