MLPP and Emergency Call Parameters

Global parameter defining call priority handling.

You can also configure the feature per specific calls, using Tel Profiles ('Call Priority Mode' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profile.

Note: If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

Global parameter enabling the support for the E911 DID protocol, according to the Bellcore GR-350-CORE standard.

You can also configure the feature per specific calls, using Tel Profiles. For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profile.

Note: If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

Defines a list of “emergency” numbers.

FXS interfaces: When one of these numbers is dialed, the outgoing INVITE message includes the SIP Priority and Resource-Priority headers. If the user places the phone on-hook, the call is not disconnected. Instead, a Hold Re-INVITE request is sent to the remote party. Only if the remote party disconnects the call (i.e., a BYE is received) or a timer expires (configured by the [EmergencyRegretTimeout] parameter) is the call terminated.

The list can include up to four different numbers, where each number can be up to four digits long. For example:

EmergencyNumbers = ‘100’,’911’,’112’

Note: The parameter is applicable only to Tel-to-IP calls. For IP-to-Tel calls, use the [EmergencyCallAlertInfoUri] parameter to identify emergency calls.

Defines the URI of the SIP Alert-Info header, for the device to consider (identify) the incoming SIP INVITE message as an emergency call.

By default, no value is defined. If you don't configure a value, the device doesn't consider any IP-to-Tel call as an emergency call (even if the Alert-Info header is present in the incoming SIP message).

Note: The parameter is applicable only to IP-to-Tel calls. For Tel-to-IP calls, use the [EmergencyNumbers] parameter to identify emergency calls.

Enables the device to block device resets that are triggered through CLI (reload command) during active emergency calls and for a period (configured by this parameter) after the call ends (regardless of whether it was successfully established or not).

The valid value is -1 to 3600 (in seconds). A value of -1 disables the feature and allows restarts during and after emergency calls.

Note: The parameter is applicable to IP-to-Tel and Tel-to-IP emergency calls.

Defines the time (in minutes) that the device waits before tearing-down an emergency call (configure by the [EmergencyNumbers] or [EmergencyCallAlertInfoUri] parameters). Until this time expires, an emergency call can only be disconnected by the remote party, typically, by a Public Safety Answering Point (PSAP).

The valid range is 1 to 30. The default is 10.

Defines the DiffServ value (differentiated services code point/DSCP) used in IP packets containing SIP messages that are related to MLPP calls. The parameter defines DiffServ for incoming MLPP calls with the Resource-Priority header.

The valid range is 0 to 63. The default is 50.

Defines the index of the Precedence Ringing tone in the Call Progress Tones (CPT) file. This tone is used when the parameter CallPriorityMode is set to 1 and a Precedence call is received from the IP side.

The valid range is -1 to 16. The default is -1 (i.e., plays standard ringing tone).

Defines the E911 (or Emergency Telecommunication Services/ETS) MLPP Preemption mode:

Defines if the device adds the SIP 'resource-priority' tag to the SIP Require header of INVITE messages for Tel-to-IP calls.

Note: The parameter is applicable only to MLPP priority call handling (i.e., only when the CallPriorityMode parameter is configured to [1]).

Multiple Differentiated Services Code Points (DSCP) per MLPP Call Priority Level (Precedence) Parameters

The MLPP service allows placement of priority calls, where properly validated users can preempt (terminate) lower-priority phone calls with higher-priority calls. For each MLPP call priority level, the DSCP can be set to a value from 0 to 63. The Resource Priority value in the Resource-Priority SIP header can be one of the following:

Defines the RTP DSCP for MLPP Routine precedence call level.

The valid range is -1 to 63. The default is -1.

Note: If set to -1, the DiffServ value is taken from the global parameter PremiumServiceClassMediaDiffServ or as defined in IP Profiles per call.

Defines the RTP DSCP for MLPP Priority precedence call level.

The valid range is -1 to 63. The default is -1.

Note: If set to -1, the DiffServ value is taken from the global parameter PremiumServiceClassMediaDiffServ or as defined in IP Profiles per call.

Defines the RTP DSCP for MLPP Immediate precedence call level.

The valid range is -1 to 63. The default is -1.

Note: If set to -1, the DiffServ value is taken from the global parameter PremiumServiceClassMediaDiffServ or as defined in IP Profiles per call.

Defines the RTP DSCP for MLPP Flash precedence call level.

The valid range is -1 to 63. The default is -1.

Note: If set to -1, the DiffServ value is taken from the global parameter PremiumServiceClassMediaDiffServ or as defined in IP Profiles per call.

Defines the RTP DSCP for MLPP Flash-Override precedence call level.

The valid range is -1 to 63. The default is -1.

Note: If set to -1, the DiffServ value is taken from the global parameter PremiumServiceClassMediaDiffServ or as defined in IP Profiles per call.