Automated Testing for Mobility Management Entity of Long Term Evolution System 5/5/2015 Xi Chen

2 Supervisor: Prof. Jyri Hämäläinen Instructor: M.Sc. Risto Nissinen (Nokia Siemens Networks Oy) Acknowledgement

Background Test System Overview ATCA MME Tektronix G35 Robot Framework & Test Suite Agile Methodology Test suite & Test cases Results Outline

The work is done in Nokia Siemens Network Oy in Espoo. It is a research about test automation of Mobility Management Entity (MME) of LTE core network with the usage of Tektronix G35 tester. The purpose is to track the performance of ATCA hardware platform by implementing a test suite which could collect MME counters’ statistics. Background

High-level Overview of Test System ATCA (MME) Framework Tektronix G35 Framework Robot Framework Network traffic Performance data

Advanced Telecom Computing Architecture (ATCA) Open standard specification 16 slots for computer units mm high 280 mm deep ATCA hardware

Modularity, scalability and flexibility. Standardized rack size & power supply Service providers get: smaller equipment & significant energy saving ATCA hardware

Five key functional units: – Control Plane Processing Unit (CPPU) – Signaling & Mobility Management Unit (SMMU) – IP Director Unit (IPDU) – Marker & Charging Unit (MCHU) – Operation & Maintenance Unit (OMU) ATCA based MME

CPPU: transaction based mobility management SMMU: storing information of visiting subscribers into visiting subscriber database (Home Subscriber Sever) IPDU: balance the loads & connectivity MCHU: offers statistics function OMU: handles operation & maintenance functions ATCA based MME

Tektronix G35 -Traffic Procedure G35 generates network traffic Define traffic profile in G35 – Start scenario: Initialization (e.g. set eNBs) – Call scenario: Periodically attach & detach subscribers – Stop scenario: Do nothing in our work

Test suite is developed in a remote client workstation. Test suite remotely controls G35 by invoking operations that are exposed by G35 through one interface. – E.g. Remotely configure G35, start traffic, stop traffic In practice: Tektronix G35 remote control

Generic test automation framework – Open source software – Implemented in Python – Can be extended with Python, Java or other languages Robot framework

Interacts with System Under Test through Test Library Architecture of Robot framework based test

Robot framework test case Tabular syntax Constructed with keywords Keywords: Build-in keywords Imported keywords from test library User keywords

One row one step (executed row by row) Test case do not need to know what is happening underneath besides keywords Each keyword is a function call which accepts arguments. – E.g. User keyword: Add Two Numbers Robot framework test case

All test cases are encapsulated in one test suite A test suite has Setup & Teardown phases: – Setup: Initialization actions (e.g. configure G35) – Teardown: Final actions – Keep the real tests be focused in between Each test case can have its own Setup & Teardown Robot framework test suite

Aim at flexibility, adaptbility & productivity – Assume, the requirement, schedule will probably be changing during development Development cycle is a sprint – One sprint = e.g. 2 weeks – Daily Scrum – Planning meeting – Review meeting Agile methodology - Scrum

Test suite - overview Initialization Organize directories structure for test results Configure G35 working environment Configure SSH feature on ATCA Set traffic profile on G35 Statistics Collection (ATCA & Tektronix) Details are explained on the following slides Results Generation Main 3 phases

Test cases G35 & MME preparation Start the traffic Periodically Collect Statistics (G35 & ATCA) of traffic period Stop the traffic Wait & Collect Statistics (G35 & ATCA) of plus period Final step Initial statistics collection

The essential part of the test sutie is counters’ statistics collection for both G35 & ATCA Counters’ statistics collection for G35: – Python function on remote client gets a list of counters defined in G35 & access the values Counters’ statistics collection for ATCA: – Test case establish SSH connection to the computer units on ATCA – Send Man Machine Language (MML) commands to get counters value Test suite – statistics collection

Computer units on ATCA: – OMU: Operation & Management Unit – CPPU: Control Plane Processing Unit – MCHU: Market & Charging Unit – SMMU: Signaling & Mobility Management Unit Test case establish a telnet connection to ACTA  start a remote session to the computer unit  send MML commands Test suite – ATCA statistics collection

Track CPU loads of all computer units on ATCA Make sure the CPU loads are in acceptable level CPU loads are tracked simultaneously by running a python script which implements the multithreading feature. Test suite – ATCA CPU loads tracking

Step 1: data extraction Plain text  list of strings Step 2: String formatting Each string in the list  “Start Time Period, Counter Number, Counter Name, Counter Value”  One record Step 3: Recording records are written to *.dat file Step 4: Graph generating Use Gunplot to generate statistic graph from DAT file Test suite – Statistic recording & graph generating

Three user input values for the test suite run – Traffic period & Plus period & Record duration Traffic period: Total period spends on periodical counters collection after traffic is started Plus period: The period spends on counters collection after traffic is stopped Record duration: The period for each round of counters collection Time domain – user inputs for test run

Time domain - all test steps Start traffic Periodical statistics collection (of traffic period) Stop traffic last statistics collection (of plus period) Final step (stop to measure) ~22s 0s ~nrOfRound * (44s+wait) User defined duration period 0s ~plusPeriod+44s ~22s Next Slide Initial statistics collection ~44s G35 & MME preparation

Stop (User defined) Traffic period Plus period Counters Collection Statistics Recording & data parsing,organization & write to files Wait until duration is over Duration (1round) Time domain - counters collection part

Results directory

Result graph – ATCA counters

Result graph – G35 counters

Result graph – CPU loads of CPPU

G35 & MME preparation ** Start the traffic Periodically Collect Statistics (G35 & ATCA) of traffic period * Stop the traffic Wait & Collect Statistics (G35 & ATCA) of plus period * Final step * 1.Prepare for the G35 counters(~2s) 2.Set timer for counters measurement from MME memory (~20s) *TOPTEN (~22s) *Stop to measure counters from MME memory (~20s) ~22s 0s ~44s Tek: ~15s(SE) <2s(classic) SMMU: ~0s MME : ~0s TOP: ~22s 1 round org. & files: ~6s 0s ~plusPeriod+44s ~20s *TOPTEN (~22s) Initial statistics collection CPPU: ~1s Results of time measurements

Automated testing for MME is found to be very important. It provides an efficient way to generate a clear picture of the performance of MME. It is helpful when improving the quality of MME Conclusion

Thank you! & Questions?