Overview
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.The SBC supports the following HPC capabilities:
- Identification of an HPC call based on the presence of either a GETS-Access Number (AN), or GETS-Number Translation (NT) string.
- Rejection of a call based on the presence of GET-Feature Code (FC) string.
- Identification of an HPC call based on the code point in the Calling Party Category (CPC) parameter of the ISUP MIME.
- Prioritization or rejection of a call based on Resource-Priority Header (RPH) r-values in an initial INVITE. The SBC also processes mid-call RPH.
- Generation of an RPH for inclusion in egress SIP messages.
- Support for early or late HPC call classification.
- Detection and logging of error conditions.
- HPC Call Admission Controls - ingress CAC for early HPC classified calls, and egress CAC treatment for early and late HPC classified calls.
- Call Queuing, if an HPC call request fails to get a resource it is queued; when the required resource is available, the processing resumes.
- Exemption of HPC messages from congestion control.
- DSCP marking and priority treatment for HPC packets - SIP, Diameter and Media packets.
- High Priority Media Port Range (HPMPR) - packets received on ports in (HPMPR) are prioritized.
- Statistics and alarms for monitoring HPC traffic.
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
Caution
Preferential servicing of HPC calls is conditional on the installation of NW-HPC license on the EMS. For more information on EMS licenses, refer to the EMS documentation Licensed Applications and Features.
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.
This section describes the CLI syntax and parameter descriptions of the HPC Call Profile.
Command Syntax
% set profiles services hpcCallProfile <hpcCallProfile name>
dscp <egress | ingress>
useRecvdValue <diabled | enabled>
dscpValue <0-63>
getsStrings
accessNumber an <3-10 digits>
featureCode fc <3-10 characters>
numberTranslation nt <3-10 digits>
queue
length <1-256>
state <disabled | enabled>
timeout <1-90>
rph
egress
nonEtsWps <dontInclude | include>
validEtsWps <dontInclude | include>
etsCpcPrecedence <cpc | ets | hpc>
etsDefaultValue <0-4>
includeAcceptIn417 <disabled | enabled>
includeRequire <disabled | enabled>
ingress
invalidEtsWps <ignore | reject>
nonEtsWps <accept | ignore>
validEtsWps <accept | ignore | reject>
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. |
dscp | The SBC uses the DSCP value received in the initial INVITE for the DSCP marking of the SIP message. egress - Use to relate dscp to the egress trunk group. Use the following flag for further configuration:useRecvdValue - When the HPC call profile attaches to a trunk group acting as an egress trunk group, use this flag to control DSCP marking for SIP messages the SBC sends forward (for example, INVITE or ACK).
disabled (default)enabled
ingress - Use to relate dscp to the ingress trunk group. Use the following flag for further configuration:
useRecvdValue - When the HPC call profile attaches to a trunk group acting as an ingress trunk group, use this flag to control DSCP marking for SIP messages the SBC sends backward (for example, 18x or 200 OK).
disabled (default) enabled
|
dscpValue | <0-63> – The DSCP code for the HPC Call. |
getsStrings | A set of Government Emergency Telecommunications Service (GETS) Access Number (AN), Number Translation (NT), and Feature Code (FC) strings that the SBC uses to determine whether a call is an HPC call or is rejected. accessNumber an < 3-10 digits> - The SBC classifies HPC calls using digits in the Request-URI of an initial INVITE request that match GETS-AN. You can configure a maximum of 10 GETS-AN strings.
featureCode fc < 3-10 characters without visual separators> - The SBC rejects HPC calls using strings in the Request-URI of an initial INVITE request that match GETS-FC. You can configure a maximum of 4 GET-FC strings.
numberTranslation nt < 3-10 digits> - The SBC classifies HPC calls using digits in the Request-URI of an initial INVITE request that match GETS-NT. You can configure a maximum of 10 GETS-NT strings.
|
queue | Use this parameter to configure HPC call queuing for trunk groups. length <1-256> - Specifies the maximum number of calls that can simultaneously queue at each trunk group. Default: 5 .state - Use this flag to enable or disable the queuing of HPC calls.disabled (default)enabled Note: Do not enable HPC call queuing for ingress and egress trunk groups simultaneously. timeout <1-90> - Specifies the maximum time (in seconds) that an HPC call remains queued before the SBC stops the attempt to connect the call in the associated trunk group. Default: 30. Note: When call is queued on the egress trunk group and the queue timer expires, the SBC sends a 408 response towards the ingress side to release the queued call. For the same scenario in a GW-GW call, the ingress SBC sends a 503 response instead of 408.
Note: By default, the SBC sends a response code 600 when the call queue is full. To configure the SBC to send the response code 503 when the call queue is full, execute similar commands as described below:
% set profiles signaling sipCauseCodeMapping cpcToSipCauseMapProfile
TEST baseProfile defaultCpcSip causeMap 161 sipCause 503
% set addressContext default zone ZONE1 sipTrunkGroup INGRESS_TG signaling causeCodeMapping cpcSipCauseMappingProfile TEST
% commit
|
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. egress - Determines how the SBC handles the ets and wps namespaces in the RPH (built by the SBC).nonEtsWps - Determines if the SBC includes or does not include namespaces other than ets and wps in the RPH (built by the SBC).dontInclude (default)
include
validEtsWps - Determines if the SBC includes or does not include valid ets and wps namespaces in the RPH (built by the SBC).dontInclude include (default)
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
ingress - Determines how the SBC handles namespaces in the received RPH.invalidEtsWps - Determines if the SBC ignores or rejects invalid ets and wps namespaces in the RPH of an ingress SIP INVITE request.
nonEtsWps - Determines if the SBC accepts or ignores namespaces other than ets and wps in the RPH of an ingress SIP INVITE request.
validEtsWps - Determines if the SBC accepts, ignores, or rejects valid ets and wps namespaces in the received RPH.
accept (default)ignore reject
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
Assuming all other parameters and flags have their default values, the following command example shows a minimal configuration for hpcCallProfile
:
% set profiles services hpcCallProfile testHpcProfile
% commit
To enable the hpcCallProfile
created in the previous example, with an allowed dscpValue
:
% set profiles services hpcCallProfile testHpcProfile dscpValue 50 stated enabled
% commit
To enable useRecvdValue
for dscp egress
:
% set profiles services hpcCallProfile testHpcProfile dscp egress useRecvdValue enabled
% commit
To enable useRecvdValue
for dscp ingress
:
% set profiles services hpcCallProfile testHpcProfile dscp ingress useRecvdValue enabled
% commit
To configure a GETS-AN string:
% set profiles services hpcCallProfile testHpcProfile getsStrings accessNumber an 7106274387
% commit
To configure a GETS-FC string:
% set profiles services hpcCallProfile testHpcProfile getsStrings featureCode fc *272
To configure a GETS-NT string:
% set profiles services hpcCallProfile testHpcProfile getsStrings numberTranslation nt 7102001234
% commit
To configure a HPC call queue:
% set profiles services hpcCallProfile testHpcProfile queue length 50 state enabled timeout 60
% commit
Caution
Do not enable HPC call queuing for ingress and egress trunk groups simultaneously.
To configure RPH for the egress of a HPC Call Profile:
% set profiles services hpcCallProfile testHpcProfile rph egress nonEtsWps include validEtsWps dontInclude
To configure RPH for the ingress of a HPC Call Profile:
% set profiles services hpcCallProfile testHpcProfile rph ingress invalidEtsWps reject nonEtsWps ignore validEtsWps accept
% show profiles services hpcCallProfile testHpcProfile
state enabled;
rph {
ingress {
invalidEtsWps reject;
validEtsWps accept;
nonEtsWps ignore;
}
egress {
validEtsWps dontInclude;
nonEtsWps include;
}
}
getsStrings {
featureCode {
fc *272;
}
accessNumber {
an 7106274387;
}
numberTranslation {
nt 7102001234;
}
}
queue {
state enabled;
length 50;
timeout 60;
}
dscp {
egress {
useRecvdValue enabled;
}
}
dscpValue 50;
To delete a configured HPC call profile:
% delete profiles services hpcCallProfile testHpcProfile
% commit