Features/Extension Monitoring/Ringing

1. Ext 1 monitors Ext 2
2. Ext C calls monitored Ext 2

1. Ext 2 sends NOTIFY to monitoring Ext 1
   • the subscription event is dialog
   • the subscription is active (not expired).
   • the dialog state has been changed on the recipient side (Ext 2)
   • the dialog state is early
   • the call-id the dialog state change refers to
   • the <remote> element containing the identity / target uri of Ext C
   • the <local> element containing the identity / target uri of Ext 2
2. The NOTIFY is accknowledged by Ext 1

Received from ... 

NOTIFY sip:Ext 1...
Via: ...
From: <sip:Ext 2...
To: <sip:Ext 1>...
Call-ID: ...
CSeq: 10009 NOTIFY
Max-Forwards: 70
Contact: ...
Event: dialog
Subscription-State: active;expires=193
Content-Type: application/dialog-info+xml
Content-Length: 486

<?xml version="1.0"?>
 <dialog-info
  xmlns="urn:ietf:params:xml:ns:dialog-info"
  version="2"
  state="full"
  entity="sip:Ext C">
  <dialog id="3c2e4a6f09c4-f4s1udjura9v@snom360-000413230D7D"
   call-id="3c2e4a6f09c4-f4s1udjura9v@snom360-000413230D7D"
   direction="recipient">
   <state>early</state>
   <remote>
    <identity>sip:Ext C</identity>
    <target uri="sip:Ext C"/>
   </remote>
   <local>
    <identity>sip:Ext 2</identity>
    <target uri="sip:Ext 2"/>
   </local>
  </dialog>
 </dialog-info>

-------------------------------------------------------------

Sent to ...

SIP/2.0 200 Ok
Via: ...
From: <sip:Ext 2...
To: <sip:Ext 1>...
Call-ID: ...
CSeq: 10009 NOTIFY
Content-Length: 0

Received from ...:

NOTIFY sip:Ext 1...
Via: ...
From: <sip:Ext 1...
To: <sip:Ext 1...
Call-ID: ...
CSeq: 20137 NOTIFY
Max-Forwards: 70
Contact: ...
Event: dialog
Subscription-State: active;expires=194
Content-Type: application/dialog-info+xml
Content-Length: 487 

<?xml version="1.0"?>
<dialog-info
 xmlns="urn:ietf:params:xml:ns:dialog-info"
 version="34"
 state="full"
 entity="sip:485@...">
 <dialog id="3c3de88ee7ef-rys8fzu4e2ei@snom360-000413230D7D"
  call-id="3c3de88ee7ef-rys8fzu4e2ei@snom360-000413230D7D"
  direction="recipient"
 ><state>early</state>
 <remote>
    <identity>sip:Ext C</identity>
    <target uri="sip:Ext C"/>
   </remote>
   <local>
    <identity>sip:Ext 2</identity>
    <target uri="sip:Ext 2"/>
   </local>
 </dialog>
</dialog-info>

--------------------------------------------------------------------

Sent to ...:

SIP/2.0 200 Ok
Via: ...
From: <sip:Ext 1...
To: <sip:Ext 1...
Call-ID: ...
CSeq: 20137 NOTIFY
Content-Length: 0

The "Calls" screen on snom360/370 displays is triggered (Dialog-Info Call Pickup <ON>), e.g. Ext C = 535 and Ext 2 = 484:

Call pick-up is possible:

• by pressing the function keys ("Extension" / "BLF" (from 7.1.33)) next to the flashing LED.
• by selecting a "ringing" call from the "Calls" screen.

Call pick-up is possible:

• by selecting a "ringing" call from the "Calls" screen.

1. Ext 1 monitors Ext 2
2. Ext C calls monitored Ext 2
3. Ext 2 sends NOTIFY to monitoring Ext 1
   • the subscription event is dialog
   • the subscription is active (not expired).
   • the dialog state has been changed on the recipient side (Ext 2)
   • the dialog state is early
4. The NOTIFY is accknowledged by Ext 1

Received from ...:

NOTIFY sip:Ext 1 SIP/2.0
Via: ...
From: <sip:Ext 2...
To: <sip:Ext 1>...
Contact: <sip:Ext 2>
Call-ID: ...
CSeq: 110 NOTIFY
User-Agent: Asterisk PBX
Max-Forwards: 70
Event: dialog
Content-Type: application/dialog-info+xml
Subscription-State: active
Content-Length: 223

<?xml version="1.0"?>
 <dialog-info xmlns="urn:ietf:params:xml:ns:dialog-info"
  version="8" state="full" entity="sip:Ext 2">
  <dialog id="2015"
   direction="recipient">
   <state>early</state>
  </dialog>
 </dialog-info>

-------------------------------------------------------------

Sent to ...:
 
SIP/2.0 200 Ok
Via: ...
From: <sip:Ext 2...
To: <sip:Ext 1>...
Call-ID: ...
CSeq: 110 NOTIFY
Content-Length: 0

Call pick-up is possible:

• by pressing the function keys configured as "BLF" (from 7.1.33) next to the flashing LED.
• by selecting a "ringing" call from the "Calls" screen.