- What it does
- Configuration
- What you need
- Setting up CAP based online charging
- I want to…
- Enable CAP charging
- Disable CAP charging
- Change the SCP that the CAP charging service communicates with
- Generate and send a charging GT containing location information for a subscriber to the SCP
- Disable sending of the charging GT to the SCP
- Only invoke the CAP charging service for terminating subscribers when they are roaming in a foreign country
- Always invoke the CAP charging service for terminating subscribers regardless of their location
- Use O-IM-CSI data from the HLR on originating calls
- Use VT-IM-CSI data from the HLR on originating calls
- Use O-IM-CSI data from the HLR on terminating calls
- Use VT-IM-CSI data from the HLR on terminating calls
- Disable retrieval of IM-CSI data from the HLR
- I want to…
What it does
When CAP online charging is in use, the Rhino VoLTE TAS functions as an IM-SSF (IP Multimedia Service Switching Function) and communicates with an SCP in a GSM network. At various points in the SIP signalling for the call the Rhino VoLTE TAS will translate the SIP to the equivalent CAP signalling towards the SCP, to give it the opportunity to intervene in call processing. Through this the SCP can provide a charging service. The exact details of how and when the Rhino VoLTE TAS will signal the SCP is determined by subscriber specific IM-CSI data in the HLR.
CAP online charging requires that integration with an SCP is set up.
To do this, the SCCP (Signalling Connection Control Part) address of the SCP must be set in the scf-address
field.
CAMEL Application Part (CAP) is a GSM protocol, so naturally can only be used with GSM networks. |
The Rhino VoLTE TAS supports CAP phase 2 and phase 3 triggers.
IM-CSI
The IM-CSI (IP multimedia CAMEL subscription information) is subscriber data retrieved from the HLR that is used to determine when and how to do SIP to CAP translation. There are different versions of the IM-CSI for the originating and terminating legs of the call; they are the O-IM-CSI and the VT-IM-CSI respectively. The Rhino VoLTE TAS can be configured to retrieve either the O-IM-CSI or the VT-IM-CSI independently of whether it is acting as an originating or terminating TAS.
The IM-CSI that is fetched on:
-
an originating TAS instance is determined by the
originating-tdp
field. -
the terminating TAS instance is determined by the
terminating-tdp
field.
Both fields can take the same values, which are numbers that correspond to CAP TDPs (trigger detection points).
The following values are valid for these fields.
TDP number | TDP name | IM-CSI retrieved |
---|---|---|
2 |
Collected_Info |
O-IM-CSI |
3 |
Analysed_Info |
O-IM-CSI |
12 |
Terminating_Attempt_Authorised |
VT-IM-CSI |
Location information
Information about a subscriber’s current country and access network can be sent to the SCP in the form of a charging GT (global title).
The format of the charging GT is configured in the format
field,
and it is made up from any combination of: fixed digits, the mobile country code (MCC), the mobile network code (MNC), and/or the two letter ISO country code.
The value of the field should match any fixed digits to be included in the charging GT, with {mcc}
, {mnc}
, and/or {iso}
tags inserted where those values should be substituted in.
For example, 12345{mcc}{mnc}
results in a charging GT that always starts with 12345
and has the current MCC and MNC for the subscriber appended on the end.
The unknown-location
field can be used to set a default charging GT,
which is used when a subscriber’s location cannot be determined.
When a subscriber receives a call, the CAP charging service is always invoked. This can be changed so that the service is only used for terminating calls when the charging GT data indicates that the subscriber is roaming in a foreign country.
Configuration
CAP based charging is only available on GSM networks. |
The example for sentinel-volte-gsm-config.yaml shows example configuration
relevant to CAP charging in the sentinel-volte/charging
section.
What you need
-
❏ The SCCP address of the GSM charging SCP.
-
❏ The TDP(s) to use when retrieving IM-CSI data from the HLR.
-
❏ Whether or not to send location information to the SCP.
If sending location information to the SCP:
-
❏ The format to sent the information in (see Location information).
-
❏ A default value to send when a subscriber’s location cannot be determined.
Setting up CAP based online charging
I want to…
Enable CAP charging
In the charging
section,
set the gsm-online-charging-type
to either cap
or cap-ro
for mixed CAMEL/Ro deployments:
gsm-online-charging-type: cap
Also in the charging
section:
cap-charging:
imssf:
scf-address: "type=C7,ri=pcssn,pc=6,ssn=156"
-
Ensure there is a
cap-charging
section. -
Ensure there is an
imssf
section. -
Set the
scf-address
to the SCCP address of the SCP that the Rhino VoLTE TAS should communicate with.
Disable CAP charging
In the charging
section,
set the gsm-online-charging-type
to disabled
:
gsm-online-charging-type: disabled
Comment out the entire cap-charging
section:
# cap-charging:
# imssf:
# imcsi-fetching:
# originating-tdp: 2
# terminating-tdp: 12
# charging-gt:
# format: "6422142{iso}"
# unknown-location: "64221429090"
# only-charge-terminating-call-if-international-roaming: false
# scf-address: "type=C7,ri=pcssn,pc=6,ssn=156"
Change the SCP that the CAP charging service communicates with
In the imssf
section,
set the scf-address
to the SCCP address of the new SCP:
scf-address: "type=C7,ri=pcssn,pc=6,ssn=156"
Generate and send a charging GT containing location information for a subscriber to the SCP
In the imssf
section:
charging-gt:
format: "6422142{iso}"
unknown-location: "64221429090"
-
Add a
charging-gt
section. Inside it add:-
a
format
field specifying how the location information should be delivered. It can be made up from fixed digits and any of these tags:{mcc}
,{mnc}
, and/or{iso}
; which will substitute in the MCC, MNC, and ISO two letter country code respectively. -
a
unknown-location
field indicating what to send to the SCP if location information cannot be obtained.
-
Related section: Location information
Disable sending of the charging GT to the SCP
In the imssf
section,
comment out the entire charging-gt
section:
# charging-gt:
# format: "6422142{iso}"
# unknown-location: "64221429090"
Related section: Location information
Only invoke the CAP charging service for terminating subscribers when they are roaming in a foreign country
In the charging-gt
section,
set the only-charge-terminating-call-if-international-roaming
to true
:
only-charge-terminating-call-if-international-roaming: true
Related section: Location information
Always invoke the CAP charging service for terminating subscribers regardless of their location
In the charging-gt
section,
set the only-charge-terminating-call-if-international-roaming
to false
:
only-charge-terminating-call-if-international-roaming: false
Related section: Location information
Use O-IM-CSI data from the HLR on originating calls
In the charging
section:
cap-charging:
imssf:
imcsi-fetching:
originating-tdp: 2
-
Ensure that a
cap-charging
section is present. -
Ensure that a
imssf
section is present. -
Ensure that a
imcsi-fetching
section is present.-
Set the
originating-tdp
to2
or3
.
-
Related section: IM-CSI
Use VT-IM-CSI data from the HLR on originating calls
In the charging
section:
cap-charging:
imssf:
imcsi-fetching:
originating-tdp: 12
-
Ensure that a
cap-charging
section is present. -
Ensure that a
imssf
section is present. -
Ensure that a
imcsi-fetching
section is present.-
Set the
originating-tdp
to12
.
-
Related section: IM-CSI
Use O-IM-CSI data from the HLR on terminating calls
In the charging
section:
cap-charging:
imssf:
imcsi-fetching:
terminating-tdp: 2
-
Ensure that a
cap-charging
section is present. -
Ensure that a
imssf
section is present. -
Ensure that a
imcsi-fetching
section is present.-
Set the
terminating-tdp
to2
or3
.
-
Related section: IM-CSI
Use VT-IM-CSI data from the HLR on terminating calls
In the charging
section:
cap-charging:
imssf:
imcsi-fetching:
terminating-tdp: 12
-
Ensure that a
cap-charging
section is present. -
Ensure that a
imssf
section is present. -
Ensure that a
imcsi-fetching
section is present.-
Set the
terminating-tdp
to12
.
-
Related section: IM-CSI
Disable retrieval of IM-CSI data from the HLR
In the imssf
section, remove or
comment out the entire imcsi-fetching
section:
imssf:
# imcsi-fetching:
# originating-tdp: 2
# terminating-tdp: 12
To disable retrieval for only:
-
originating calls, remove the
originating-tdp
. -
terminating calls, remove the
terminating-tdp
.
Related section: IM-CSI