INTRODUCTION

The purpose of this standard is to define procedures for testing the interoperability of RFSSs operating in trunked voice mode. Each RFSS is interconnected using an ISSI to test the interoperability of RFSSs from different manufacturers, different model RFSSs from the same manufacturer, and different RFSS software versions.¹

Existing tests specified in TIA-102.CABC-A and its addendum(s) [3] are aimed at assessment of Common Air Interface (CAI) interoperability between a subscriber unit (SU) and its associated FNE. The set of tests described in this document extend these tests to assess ISSI interoperability utilizing multiple SUs in wide area roaming situations where multiple RFSSs and G interfaces are involved.

The approach taken in this standard is to extend the interoperability test procedures for voice operations in trunked systems described in TIA-102.CABC-A [3] from an FNE whose topology is undefined to an FNE composed of multiple RFSSs that are connected via G interfaces. From the viewpoint of the Subscriber Units, the FNE is treated as a network cloud. The Subscriber Units (SUs) and the RFSSs are tested for Interoperability using TIA- 102.CABC-A and its addendum(s) [3] prior to running the end-to-end tests for multiple- RFSSs using the ISSI. Test Suites are provided for each feature. Each Test suite provides a description of the test, applicable RFSS role combinations, expected behavior, call configuration, initial conditions and post conditions. Test Cases for the Test Suites are then developed which track and extend the Test Cases in CABC-A.

This standard tests the interoperability of RFSSs in two basic ways: (1) ISSI interoperability testing of RFSSs from two different manufacturers and (2) ISSI interoperability testing of two different Types of RFSSs from the same manufacturer. If possible, two identical RFSSs of each Type (a total of 4 RFSSs) should be used in order to test the configurations. If only one RFSS of each Type is available (for a total of two different RFSSs) then the RFSSs need to assume multiple roles in the tests. The test procedures in this document provide the test configurations and procedures for both cases.

This standard tests only two Types of RFSSs (as compared to three or more). The RFSSs are tested in all possible role combinations to ensure that the first RFSS is interoperable with the second RFSS. To ensure that three or more different physical RFSSs are interoperable with each other requires more test cases. The extended TIA-102.CABC-A interoperability testing approach for ISSI allows for testing to be performed using a Systemto- System (STS) procedural approach for the RFSSs, using SUs as a stimulus and measure of success in all call configurations.^2,3 Successful operation of the ISSI is implied through successful completion of the tests at the Unit-to-Unit level. As in all the tests specified in CABC-A, the tests specified here are also user oriented examining interoperability of a limited set of functional features and services within P25.⁴ The results of these tests can be observed and evaluated by public safety users to determine interoperability of the units under test.

Group and Unit-to-Unit call configurations are employed which utilize the ISSI and go from the simple that do not include roaming units, to the more complex which do include roaming units. Test cases are provided which span multiple WACNs and Systems and exercise the ISSI during registration, Group affiliation, call set-Up and user information transfer.

The Test Suites and Test Cases provided illustrate interoperability tests to test that two manufacturers' RFSSs can perform every supported RFSS role combination in a given Group or Unit-to-Unit call configuration. Only by verifying interoperability in each supported RFSS Role Combination can interoperability of the two RFSSs be confirmed. This test procedure observes SU operation in order to test the interoperability of the RFSS's ISSI interface. The SUs used in this procedure are not under test in this procedure but are used to provide an end-to-end stimulus to run the test and to verify the test's success or failure. To ensure proper SU operation when executing this test procedure, the interoperability of the trunking CAI utilizing the SU with an FNE should be tested first. That is, test the SUs with TIA-102.CABC-A and its addendum(s) [3] which includes tests of SUs roaming among Inter-System and Inter-WACN sites. Then execute this test procedure with SUs that have properly passed the TIA-102.CABC-A and its addendum(s) [3] test suites, including those for roaming (if roaming is required in the corresponding test case in this document). It is not necessary to execute test cases from this test procedure with every SU Type, it is sufficient to test with one SU Type that has been tested with TIA-102.CABC-A and its addendum(s) [3]. The test cases chosen from TIA-102.CABC-A and its addendum(s) [3] should match the functionality of the test cases chosen to be run in this test procedure. For example, if the test suite to be run in the ISSI interoperability test is Group Call with roaming, then that test suite is chosen from the TIA-102.CABC-A Addendum.

Some of the SUs involved in the test configuration are roaming on their respective Serving RFSS(s). The use of roaming SUs allows the Registration and Talk Group affiliation features and functions of the ISSI to be fully exercised. If the Serving RFSS of the SUs is also their Home RFSS, Registration messages will not traverse and be processed across the ISSI. A Talk Group affiliation message (if it is the first affiliation to a particular group) received from an SU will trigger group registration over the ISSI only if the SU's serving RFSS is not also the SG Home RFSS.

This standard is comprised of two clauses and two annexes. Clause 1 provides the Introduction while Clause 2 provides the normative Test Procedures for the relevant Test Suites. A general ISSI interoperability model is presented in Annex A. Annex B provides an informative description of ISSI interoperability test pre-configuration data.

¹ The Interoperability Reference Model – ISSI (IRM-I) is an Interoperability test model consisting of multiple RFSSs and G interfaces between them for a Unit-to-Unit or Group Call. This is defined in 1.2 of this document and Annex A.

² Successful completion of the tests is based on proper outcome without regard to the details involved in achieving the proper testing outcome. For a Group or Unit-to-Unit Call, the applicable RFSS functional role combinations for the multiple RFSSs that implement the ISSI are specified for each test.

³ The System-to-System (STS) approach tests units under test (UUT's) against each other.

⁴ User oriented testing does not involve the use of specialized test tools such as wireless and wireline protocol analyzers which examine communications at the message level to determine the outcome of a test.