5 Test Architectures

26.1393GPPReal-time Transport Protocol (RTP) / RTP Control Protocol (RTCP) verification proceduresRelease 17TS

5.1 General

This clause describes a set of terms and possible ways to arrange the equipment used in the tests in subsequent clauses.

The "system under test" is the device or software to be tested.

The "test instrument" is the equipment used to observe RTP/RTCP output from the system under test, and in applicable cases also RTP/RTCP output from data injection, similar to e.g. a "System Simulator" (SS) in TS 34.229-1 [12]. Depending on the test architecture used, it may also act as RTP/RTCP receiver for data sent from the system under test. The test instrument also includes possibility to extract, calculate, and store information as described by the test procedures in clause 6 of the present document.

The "data injection" is the device or equipment used to generate RTP/RTCP data sent to the system under test. It may be collocated or integrated with the test instrument. For some tests and test architectures, e.g. when two systems under test are interconnected, it may be part of the system under test. Data injection may also act as RTP/RTCP receiver for data sent from the system under test, e.g. when the test instrument does not include this functionality.

In all tests, it is assumed that both systems under test, the test instrument, and the data injection are active and connected to the network before starting the test procedure.

Other test architectures than the ones suggested here may be used.

5.2 Active Test Instrument

In this test architecture, depicted in Figure 5.2-1, the test instrument is capable of both observing RTP/RTCP traffic and acting as fully functional counterpart to the system under test, including both RTP/RTCP sender and receiver.

Figure 5.2-1: Active Test Instrument

5.3 Passive Test Instrument

In this test architecture, depicted in Figure 5.3-1, the test instrument is only passively observing RTP/RTCP traffic, and data injection including both RTP/RTCP sender and receiver is acting as a counterpart to the system under test.

Figure 5.3-1: Passive Test Instrument

5.4 Interconnected Systems Under Test

In this test architecture, the test instrument is either only passively observing RTP/RTCP traffic, depicted in Figure 5.4-1, or actively forwarding RTP/RTCP traffic, depicted in Figure 5.4-2, while two interconnected systems under test act as each other’s RTP/RTCP sender and receiver counterparts.

Figure 5.4-1: Interconnected Systems Under Test with Passive Test Instrument

Figure 5.4-2: Interconnected Systems Under Test with Active Test Instrument

5.5 Interconnected Systems Under Test with Data Injection

In this test architecture, depicted in Figure 5.5-1, the test instrument is only passively observing RTP/RTCP traffic, while two interconnected systems under test act as each other’s RTP/RTCP sender and receiver counterparts. Under the assumption that the systems under test lack necessary data injection capabilities, a separate data injection is included in the RTP/RTCP path with capability to make RTP/RTCP modifications on-path. Examples of such RTP/RTCP modifications could be setting certain sequence number or timestamp start values, dropping packets, duplicating packets, re-ordering packets, or adjusting the timing of sent packets. Individual test case procedures provide what RTP/RTCP modifications are applicable.

Figure 5.5-1: Interconnected Systems Under Test with Data Injection