Emergency E911 Phone Number Services; Multilevel Precedence And Preemption - AudioCodes Mediant 3000 User Manual

Interrogation request). Some support both these requests. Therefore, the device can
be configured to disable this feature, or enable it with one of the following support:
•
Responds to MWI Activate requests from the PBX by sending SIP NOTIFY MWI
messages (i.e., does not send MWI Interrogation messages).
•
Send MWI Interrogation message, but don't use its result. Instead, wait for MWI
Activate requests from the PBX.
•
Send MWI Interrogation message, use its result, and use the MWI Activate
requests.

18.5.2.5 Emergency E911 Phone Number Services

The device supports emergency phone number services.
18.5.2.5.1 Pre-empting Existing Calls for E911 IP-to-Tel Calls
If the device receives an E911 call from the IP network destined to the Tel, and there are
unavailable channels (e.g., all busy), the device terminates one of the calls (arbitrary) and
then sends the E911 call to that channel. The preemption is done only on a channel
pertaining to the same Trunk Group for which the E911 call was initially destined and if the
channel select mode (configured by the ChannelSelectMode parameter) is set to other
than "By Dest Number" (0).
The preemption is done only if the incoming IP-to-Tel call is identified as an emergency
call. The device identifies emergency calls by one of the following:

The destination number of the IP call matches one of the numbers defined by the
EmergencyNumbers parameter. (For E911, you must defined this parameter with the
value "911".)

The incoming SIP INVITE message contains the "emergency" value in the Priority
header.
This feature is enabled by setting the CallPriorityMode parameter to "Emergency" (2).
Note:

18.5.2.6 Multilevel Precedence and Preemption

The device's Multilevel Precedence and Preemption (MLPP) service can be enabled using
the CallPriorityMode parameter. MLPP is a call priority scheme, which does the following:

Assigns a precedence level (priority level of call) to specific phone calls or messages.

Allows higher priority calls (precedence call) and messages to preempt lower priority
calls and messages (i.e., terminates existing lower priority calls) that are recognized
within a user-defined domain (MLPP domain ID). The domain specifies the collection
of devices and resources that are associated with an MLPP subscriber. When an
MLPP subscriber that belongs to a particular domain places a precedence call to
another MLPP subscriber that belongs to the same domain, MLPP service can
preempt the existing call that the called MLPP subscriber is on for a higher-
precedence call. MLPP service availability does not go across different domains
MLPP is typically used in the military where for example, high-ranking personnel can
preempt active calls during network stress scenarios, such as a national emergency or
degraded network situations.
The Resource Priority value in the Resource-Priority SIP header can be any on of those
listed in the table below. A default MLPP call Precedence Level (configured by the
SIP User's Manual
This feature is applicable to CAS, and ISDN interfaces.
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Mediant 3000
Document #: LTRT-89712