Features/Extension Monitoring/Ringing

From Snom User Wiki

Jump to: navigation, search
Individual Subscriptions (RFC 4235) Event List Subscriptions (RFC 4662)


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


Example#1 SIP Message Flow with PBXnSIP PBX
  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
Individual Subscriptions (RFC 4235) Event List Subscriptions (RFC 4662)
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
Result#1: Busy Lamp Field (BLF)
The LEDs of the function keys configured as "Extension" / "BLF" (from 7.1.33) start flashing. The BLF feature is NOT AVAILABLE when using event list subscription.
Result#2: "Calls" screen

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


Result#3: "Call Pick-Up"

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.


Example#2 Asterisk (1.4.X unpatched):
  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
Asterisk does NOT support this feature (1.2 / 1.4).
Individual Subscriptions (RFC 4235) Event List Subscriptions (RFC 4662)
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
Asterisk does NOT support this feature (1.2 / 1.4).
Result#1: Busy Lamp Field (BLF)
The LEDs of the function keys configured as "Extension" / "BLF" (from 7.1.33) start flashing. Asterisk does NOT support this feature (1.2 / 1.4).
Result#2: "Calls" screen
The "Calls" screen is NOT triggered due to the absence of the <remote> / <local> elements. Asterisk does NOT support this feature (1.2 / 1.4).
Result#3: "Call Pick-Up"

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.
Asterisk does NOT support this feature (1.2 / 1.4).
Personal tools
Interoperability