The HSS Nodal Test Case
Sh is the interface between an Application Server (AS) and Home Subscriber Server (HSS) for storing, retrieving, and modifying user data. HSS is used as a repository for information storage that consists of transparent and non-transparent data. Transparent data contains information that the HSS does not understand, and non-transparent data contains information that HSS does understand. The AS can subscribe to receive notifications from the HSS when any of the subscribe data changes, request for data, and update user profile stored in the HSS.
Cx interface is used between CSCFs and HSS for storing and retrieving data related to the subscriber, which includes the state of the user, current assigned S-CSCF, and authentication. Cx interface is used between I-CSCF and HSS, and S-CSCF and HSS. In order to provide service to the subscriber, user profile, which includes service profiles, are stored in the HSS and downloaded by the S-CSCF. The S-CSCF, based on the service profiles provided by the HSS through Cx interface, can be used to provide additional services by sending information to associated Application Servers (AS). The interface between the S-CSCF and the AS is out of the scope of this document.
A subscriber is assigned an S-CSCF based on a number of factors, which may include server capabilities required for the subscriber, which is stored within HSS and provided to I-CSCF over Cx interface. Upon registration to IMS network of the subscriber, the I-CSCF uses Cx interface to retrieve S-CSCF information from the HSS. Depending on the information provided by the HSS, over Cx interface, the I-CSCF will select an S-CSCF for the subscriber, which then gets assigned accordingly. Requests from the user equipment are sent, eventually, to I-CSCF and forwarded to the assigned S-CSCF.
The HSS is used to store the user related data that is used by both I-CSCF and S-CSCF. If authentication is enabled, the S-CSCF also issues requests for authentication information that is provided by the HSS over Cx interface.
The HSS Nodal Testing Case
Application Server (AS) Emulation:
When emulating an AS (Application Server) in an HSS Nodal test case, Landslide supports the following functions:
- Request user data from the HSS
- Subscribe to notifications from the HSS upon data changes
- Update user profile stored in the HSS
- Customize data-references and XML content of requests
Note: Currently, Sh interface can only be enabled when LTE Version >= 11.4.0 is selected.
AS tab in HSS Nodal
In HSS Nodal test case, the AS tab for Sh interface allows the user to define requests related to user data and control the behavior of the Application Server (AS). The emulated AS may issue User Data Requests (UDR), Subscribe Notifications Requests (SNR), and Profile Update Requests (PUR). The AS tab contains common configurations for all requests such as the XML header, as well as specific parameters for each request type.
The AS may issue User Data Requests (UDR) to request for user data from the HSS. The requests include data-references to indicate the requested data to be returned from the HSS, in a User Data Answer. More than one data-reference may be included in the request.
The user data table indicates the data-reference number, name, and the expected XML tag returned from the HSS. Depending on the data-references configured to be included in the request, additional fields may be enabled.
The AS may subscribe to the HSS for changes in specific user data by sending a Subscribe Notifications Request (SNR), which includes data-references that the HSS should notify the AS about. Similarly to UDR, the SNR tab contains a table of data-references that the AS may subscribe to. Subscriptions are not mandatory and can be controlled by the user. When subscriptions are enabled a delay may be introduced prior to the initial subscribe, and a duration can be specified to control when the unsubscribe event will occur. Unsubscribing will inform the HSS to no longer send notifications to the AS.
If there are profile changes on the AS, the AS will send a Profile Update Request (PUR) to the HSS that includes the data-reference number of the changed data and the content in XML. Only one data-reference can be selected and included in the PUR. Profile updates are optional and can be enabled. When enabled, an initial delay can be set to postpone the start of updates. Multiple values for the data-reference can be defined to ensure subsequent requests contain different values when continuous and alternate values options are enabled. When “Alternate Values on Each Update” is checked, the defined values for the selected data-reference will be selected in round-robin. The frequency of the profile updates can also be defined.
Sh Session Measurements:
AS Node Measurements:
Connection Management Measurements
AS IP Measurements: