About DRA Testing

3GPP Diameter Routing Agent (DRA) ensures pieces of information of a same subscriber arrived from different interfaces (i.e., Gx, Rx, S9, or Gxx) gets routed to a same PCRF server. Please see the below figure 1.3a for a simple network topology diagram.

DRA (Diameter Routing Agent)

The DRA agent is deployed when there are multiple PCRF servers within a single charging realm. The Landslide DRA agent implements both IETF Diameter Redirect agent (IETF RFC 3588) and Diameter Proxy agent with a routing policy (IETF RFC 3588).

DEA (GSM Diameter Edge Agent)

GSM-A Diameter Edge Agent (DEA) easing deployment and dependency between operators by using DEA as an only entry point for all diameter messages communicating between an operator’s internal diameter servers (i.e., HSS, PCRF, DRA, etc) and outside world (other operators).

Landslide DEA functional element supports three modes of DEA, as an IETF Diameter Relay agent, IETF Diameter Proxy agent, and a Diameter agent with combined Relay and Proxy capability.

Protocols and Emulators

Nodes/Emulators	Interfaces	Protocol
HSS MME SGSN AS CSCF I/F	HSS S6a S6d Sh CX	Diameter Base Protocol (IETF RFC 3588)
PCRF AGW AF BBERF (hPCRF - vPCRF) OCS TDF	PCRF, Gx, S9 Rx Gxc Sy Sd	Diameter Base Protocol (IETF RFC 3588)
SGW - PGW	S8	GTP (GTP-C 3GPP and GTP-U 3GPP) or PMIP (IETF RFC 5213 [20])

DRA Nodal Testing

The DRA Nodal test case emulates the functional requirements of 3GPP Diameter Routing Agent (DRA) and GSM-A Diameter Edge Agent (DEA). The test case also generates and measures diameter messaging traffic sent to or received from DRA/DEA agents.

Sy Interface

The Sy reference interfaces between the Policy and Charging Rule Function (PCRF) and the Online Charging System (OCS). In DRA Nodal test case to simulate Sy interface messages, the PCRF subscribes to OCS for a given subscriber ID and policy counter ID, by sending SLR (initial).

OCS responds with SLA, which includes the policy counter status, and the pending policy counters, and with their pre-configured change time, if any.
If PCRF no longer wants to be subscribed, it sends session termination request (STR) which terminates the Sy session for the subscriber.

NOTES:

Only 1 Pending Change time is included
The Status value is calculated and decided as a string value:

Prefix S + initial value + number of SNR * increment

When error messages are the Diameter result, error code is 5570 ( unknown policy counters)

See DRA Nodal Parameters for details of configuring various test case options and parameters.

DRA Node Testing

DRA node supports redirect, relay, and proxy modes. You may configure both the peer and realm-based routing table and specify an action for each route entry. In addition, you may also define a policy for a routing action specified as a Proxy.

See DRA Node Parameters for details of configuring various test case options and parameters.

DRA + HSS and DRA + PCRF Testing

You may test a combination of a DRA Node and a real HSS (PCRF or PCEF), referred to as one-armed testing.

During one-armed testing, you may use the DRA nodal test case to test either a standalone DRA or a combination of DRA with HSS, PCRF or PCEF. The test case supports either:

One side of a diameter exchange through a real DRA communicating with real Diameter Nodes (PCRF, HSS, PCEF, MME)

Both sides of the diameter exchange, where DRA communicates with emulated Diameter nodes (PCRF, HSS, PCEF, MME).