About OCS Testing
In a OCS (Online Charging System) Node test case, Landslide emulates the OCS (Online Charging System) on the LTE network. The Ro reference point provides interface to Packet Data Network Gateway (PDN GW) SUT.
Online charging is a process where charging information for network resource usage is collected concurrently with the resource usage as in the offline charging service. However, authorization for the network resource usage is obtained by the network before using the actual resources. This authorization is granted by the Online Charging System when a request is received from the network.
When receiving a network resource usage request, the network assembles the relevant charging information and sends a charging occurrence to the OCS in real-time. The OCS then returns an appropriate resource usage authorization. The resource usage authorization may be limited in its scope (for example, volume of data or duration), therefore the authorization may have to be renewed from time to time as long as the user’s network resource usage persists.
That is, online charging is a mechanism where charging information can affect, in real-time, the service rendered and therefore a direct interaction of the charging mechanism with the control of network resource usage is required.
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Online charging for both events and sessions between CTF and the OCF is performed using the Ro reference point. The Ro reference point supports integrity protection and authentication when the CTF is outside the operator domain.
- Re — The Re reference point supports interaction between the OCF and a Rating Function (RF) in order to determine the value of chargeable events in terms of monetary or non-monetary units.
- Rc — The Rc reference point allows the interaction between the OCF and an Account Balance Management Function (ABMF) in order to access the account of the subscriber on the OCS.
- Ro — The Ro reference point supports interaction between a Charging Trigger Function and an Online Charging Function. The following information may flow across this reference point:
- Charging events for online charging from the CTF to the OCF.
- Receive Acknowledgements for these charging events from the OCF to the CTF. The acknowledgement grants or rejects the network resource usage requested in the charging event, according to the decision taken by the OCS.
- Gy — The Gy reference point is between Online Charging Systen (OCS) and Policy and Charging Enforcement Function (PCEF). Gy reference point provides the same functionality as those of reference point Ro. The major differences between Gy and Ro is that Gy is an specific instance of the Ro reference point that connects OCS from the packet-switched domain (PS) i.e. PCEF (e.g., PGW) within GGSN or OCS. Gy is available on DRA Nodal test case.
The protocol(s) crossing this reference point supports the following capabilities:
- Real-time transactions;
- Stateless mode (Event Based Charging”) and stateful mode (Session Based Charging) of operation;
- Provides its own reliability mechanisms, e.g. retransmission of charging events, to run also on unreliable transport.
In addition, the protocol supports changeover to a secondary destination (alternate OCS) in case of the primary OCF not being reachable.
Charging Trigger Function
Online charging is a process where charging information is collected in the network element in the same fashion as in offline charging. This implies that, from the functional perspective, the CTF creates the charging events used for online charging. While the accounting metrics used in online charging are generally the same as in offline charging (i.e. the charging mechanism is transparent to the Accounting Metrics Collection), the following functional enhancements concerning the Accounting Data Forwarding are supported in the CTF for online charging:
The information collected for, and included in, the online charging events is not necessarily identical to the offline charging case (i.e. the chargeable events may not necessarily be identical to those observed in offline charging);
The charging events are forwarded to the Online Charging Function (OCF) to obtain authorizsation for the chargeable event / network resource usage requested by the user;
The CTF allocates resources only after OCS grants permission;
The CTF tracks the availability of resource usage permission (quota supervision) during the network resource usage;
The CTF terminates the end user network resource usage when permission by the OCS is not granted or expires.
Rating Function (RF)
The Rating Function (RF) determines the value of the network resource usage (the charging event received by the OCF from the network) on behalf of the OCF. The OCF furnishes the necessary information, obtained from the charging event, to the RF (Rating Function) and receives in return the rating output (monetary or non-monetary units), via the Re reference point. The RF may handle a wide variety of ratable instances, such as:
- Rating of data volume (e.g., based on charging initiated by an access network entity, i.e., on the bearer level).
- Rating of session / connection time (e.g., based on charging initiated by a SIP application, i.e., on the subsystem level).
- Rating of service events (e.g., based on charging of web content.
Online Charging Function
The Online Charging Function (OCF) consists of three distinct modules, namely the Immediate Event Charging (IEC), the Session Based Charging Function (SBCF) and the Event Based Charging Function (EBCF).
- The Immediate Event Charging is responsible for charging information in real-time, when the service is rendered and therefore a direct interaction of the charging mechanism with session/service control is required.
- The Session Based Charging Function is responsible for online charging of network / user sessions, e.g., voice calls, IP CAN bearers, IP CAN session or IMS sessions.
- The Event Based Charging Function performs event-based online charging (also referred to as “content charging”) in conjunction with any application server or service NE, including SIP application servers.
OCS Node Testing
The OCS server provides online charging and Credit Control services for a SUT. Add the OCS Node test case to a test session and configure the SUT to direct OCS traffic to the server's IP address.
The test case can emulate two servers, one primary and one secondary, for failover testing and can generate messages as though they were routed by a Diameter proxy, eliminating the need for physical proxy servers.
IMPORTANT: If an OCS Node test case shares the same test server as another test case, the maximum activation rate and capacity of the nodal test case is reduced.
You can avoid these restrictions by running the OCS Node test case on another test server as shown in the diagram. |
With each test case, you define:
The server's IP address
The number of mobile subscriber accounts that can be supported
| NOTE: The maximum number of mobile subscriber accounts and maximum number of sessions per subscriber supported is determined by your license capacity. |
The mandatory and optional Diameter AVPs, total number SUTs supported via the Number of Peers (Diameter tab), and the maximum rate at which sessions can be deactivated.
The credit rating, credit pools, and MSCCs.
Optional re-authentication frequency, failover support, and failure simulation.
Measurements
Measurements collected for the OFCS Node test case are reported on the following tabs.