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High Probability of Completion (HPC) features comprise a set of functionalities that provide an enhanced probability of call completion to authorized Government Emergency Telecommunications Service (GETS) and Wireless Priority Service (WPS) users during network stress and/or congestion.

There are two methods in HPC call classification:

  • Early HPC classification—An HPC call is recognized based on the received SIP RPH content in the incoming INVITE or the code point in Calling Party's Category (CPC) parameter of the ISUP-MIME. For ANSI, the CPC parameter is National Security/Emergency Preparedness (NS/EP) and for ITU, the CPC parameter isInternationalEmergency Preference Scheme (IEPS).
  • Late HPC classification—An HPC call can also be recognized by the PSX during analysis of the Called Party Number.
Note

The SBC must be configured to use the external PSX for this feature. For more information on using the PSX for GETS / WPS, refer to the PSX documentation Government Emergency Telecommunications Service.

The SBC supports the use of different Differentiated Services Code Point (DSCP) marking for signaling traffic that is associated with HPC and non-HPC calls. To support different DSCP marking for HPC and non-HPC calls in a SIP trunk group, the dscpValue parameter in the HPC profile configuration marks HPC calls and the DSCP configuration in the SIP signaling port marks non-HPC calls. The DSCP value configured in the HPC profile takes precedence over the DSCP value configured in the SIP signaling port and applies to all outbound traffic (IPv4 and IPv6) associated with HPC calls.

The outbound SIP signaling messages associated with HPC and non-HPC calls are marked with the DSCP value configured in the SIP signaling port when the hpcCallProfile is not configured in a SIP trunk group.

Caution

Setting the DSCP on the UDP or TCP network socket is a system call, which impacts the system performance if the DSCP frequently switches between HPC and non-HPC calls. 

Note

This feature only applies to HPC calls over UDP transport. This feature does not apply to TCP transport since TCP is byte stream oriented and does not preserve message boundaries.

This section describes the CLI syntax and parameter descriptions of the HPC Call Profile.

The SBC must be configured to use the external PSX for this feature. The SBC supports configuring up to 256 HPC Call Profiles.

 

Command Syntax

% set profiles services hpcCallProfile <hpcCallProfile name>
	dscp value <0-63>
    rph 
		etsCpcPrecedence <cpc | ets | hpc>
		etsDefaultValue <0-4>
		includeAcceptIn417 <disabled | enabled>
		includeRequire <disabled | enabled> 
		rejectNotEtsDn <disabled | enabled>
		useIncomingEts <disabled | enabled>
		usePrecedence <disabled | enabled>
		useWpsPrecedence <disabled | enabled>
		wpsMlppPrecedence <mlpp | wps>
	state <disabled | enabled>

The HPC Call Profile parameters are defined below:

HPC Call Profile Parameters

 

Parameter

Description

hpcCallProfile<profile name, up to 23 characters> – HPC Call Profile name.
dscpValue<0-63> – The DSCP code for the HPC Call.
rph

Resource Priority Header (RPH) configuration options to specify how the RPH or ISUP-MIME affects call handling and building of the RPH for HPC calls.

  • etsCpcPrecedence – This parameter is used for deriving a call's CPC during ingress processing when a conflict exists between the CPC based on RPH and the ISUP-MIME (SIP-I) calling party category parameter.

    • cpc – The call's CPC parameter is derived from the ISUP-MIME CPC parameter.

    • ets – The call’s CPC parameter is derived based on the SIP RPH ETS value.

    • hpc (default) – The call’s CPC parameter is derived based on SIP RPH ETS, or else it is derived from ISUP-MIME CPC parameter.

  • etsDefaultValue <value> – Default priority value used for the ETS namespace. (range: 0-4 / default = 0)
  • includeAcceptIn417 – Enable this flag to include the Accept-Resource-Priority header when sending a 417 response.
    • disabled (default)
    • enabled
  • includeRequire – Enable this flag for the SBC to include the Require header with the resource-priority option tag in an egress INVITE.
    • disabled (default)
    • enabled
  • rejectNotEtsDn – Enable this flag for the SBC to reject a call when SBC classifies the call as HPC based on the received RPH and the PSX determines Directory Number (DN) to be a non-ETS DN.
    • disabled (default)
    • enabled
  • useIncomingEts – Enable this flag for the SBC to use the received ETS value. If set to disabled, the SBC uses the provisioned etsDefaultValue.
    • disabled (default)
    • enabled
  • usePrecedence – Specifies whether the ETS value in outgoing SIP messages for the call takes the priority/precedence value received in the ingress.
    • disabled (default) – The ETS priority value in outgoing SIP messages is derived from the etsDefaultValue, when either of the usePrecedence at the ingress trunk group’s HPC profile or useWpsPrecedence at the egress trunk group’s HPC profile fields are disabled, or when there is no incoming priority/precedence value.
    • enabled – When usePrecedence is enabled at the ingress trunk group’s HPC profile and useWpsPrecedence is enabled at the egress trunk group’s HPC profile, the ETS value in outgoing SIP messages is derived from the incoming Wireless Priority Service/Multilevel Precedence and Preemption (WPS/MLPP) priority/precedence value.
  • useWpsPrecedence – Enable this flag for the SBC to take the ETS priority value from WPS/ MLPP precedence, if available, when adding ETS. If set to disabled, the SBC uses the configured etsDefaultValue when adding ETS.
    • disabled (default)
    • enabled
  • wpsMlppPrecedence – Use this parameter to determine how to handle the call when the WPS value in the SIP RPH and a MLPP parameter in the associated ISUP-MIME indicate different handling:
    • mlpp (default) – Handle the call as indicated by the ISUP-MIME MLPP parameter.
    • wps – Handle the call as indicated by the SIP RPH WPS value.
state

Administrative state of HPC Call Profile.

  • disabled (default)
  • enabled

Command Examples

set profiles services hpcCallProfile testHpcProfile state enabled 
set profiles services hpcCallProfile testHpcProfile rph tsCpcPrecedence hpc etsDefaultValue 1 
set profiles services hpcCallProfile testHpcProfile includeAcceptIn417 enabled includeRequire enabled rejectNotEtsDn enabled useIncomingEts enabled usePrecedence enabled useWpsPrecedence enabled wpsMlppPrecedence wps
commit
show profiles services hpcCallProfile
hpcCallProfile HPCP {
    state enabled;
    rph {
        etsDefaultValue    1;
        useWpsPrecedence   enabled;
        useIncomingEts     enabled;
        usePrecedence      enabled;
        etsCpcPrecedence   hpc;
        wpsMlppPrecedence  wps;
        includeRequire     enabled;
        rejectNotEtsDn     enabled;
        includeAcceptIn417 enabled;
    }
} 
set profiles services hpcCallProfile testProfile dscpValue 10
commit
 
show profiles services hpcCallProfile testProfile
dscpValue 10;


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