Session processing includes topics related to how the Sentinel VoLTE product executes various different call flows.
Selection of MMTel and SCC functionality — how the different AS functions are able to be selected through URI parameters
Selection of charging mode — how online/offline charging is selected through URI parameters
Initial Filter Criteria — example Initial Filter Criteria for use with Sentinel VoLTE
Session Processing and the Use of HSS — how Sentinel VoLTE makes use of the HSS
Service Compositions — selection of services that execute on each SIP session
Sentinel VoLTE Session Plans — selection of features that execute inside a SIP session
Custom Headers — OpenCloud defined headers that influence session processing behaviour
Out of the box, the Sentinel VoLTE product can:
function as an SCC-AS, or an MMTel-AS for a given trigger
function as a combined SCC+MMTel-AS off a single trigger, thereby optimising performance.
perform offline charging only
perform online charging, through either acting as a Charging Trigger Function using Diameter Ro, or CAP (using the IM-SSF)
These different configurations are all available on a per-trigger basis, rather than being a "hard configuration mode".
Online charging via the CAP interface is delivered through the use of OpenCloud’s IM-SSF, and is an optionally installed component.
Different modes of operation (e.g. MMTel functionality, or SCC functionality) are determined through parameters added to the Application Server URI during initial filter criteria (iFC) configuration.
When the Sentinel VoLTE application server receives an initial SIP request (for example, an initial INVITE or third-party register request) parameters are present on the topmost route header. There are certain parameters that can be added to alter the behaviour of Sentinel VoLTE. That is to say, the iFC and application server configuration in the HSS may include URI parameters that select different sets of behaviour from the Sentinel VoLTE product.
Session plans are available that enable execution of MMTel and SCC feature sets in different combinations.
These are selected through the use of the
The specific URI parameters are discussed in the Custom Headers section.
The system charging mode can be set to:
offline only, meaning the system only writes CDRs and/or Diameter Accounting Requests (ACRs)
online charging via Diameter Ro, meaning that the system acts as a charging trigger function towards the OCS as well as writing CDRs and/or ACRs
online charging via CAMEL, meaning it includes an IM-SSF component that triggers a prepaid service control point via the CAP protocol.
The charging mode is selected through the
oc-charge-mode parameter. This is an Application Server URI parameter.
For detailed descriptions of the
oc-charge-mode parameter, see the DetermineChargeMode and Service Compositions pages.
The VoLTE Interim CDR Feature is configured to select whether interim CDRs and/or ACRs are used. It is used if Diameter Rf and/or Interim CDRs are selected during installation.