The MME Nodal test case tests a MME's capability to service MS in a simulated network. This topic will guide you through configuring and running a basic Capacity Test, and then expanding the basic test with the optional behaviors available in the test case.
After you have a functioning test session, you can build tests using other test activities and options:
You should have a basic understanding of the test system:
Prepare the system and gather information about the SUT
Add the SUT to the database if necessary
The MME SUT's SCTP and NAS (Non-Access Stratum) requirements
To configure a MME Nodal Capacity test:
The goal for the first test is to establish one PDP context with the MME to confirm the test case definition, then to successfully execute the test with increased rates and multiple sessions, and finally, to customize the more advanced protocol, MS, and test case behaviors.
Create a new test session... and add a MME Nodal test case... from the Basic library. The Test Case Settings window... opens to the Test Configuration tab.
Select the Vendor Variant.
Enter the Number of Mobile Subscribers that will be requested by the MME, Maximum Bearer per Subscriber, activate/deactivation Rates.
Network Devices — Identify the SUT and define the MME emulator
Select the MME SUT from the drop-down list.
Define one eNodeB emulator on the Control Node sub-tab. Select a Physical Interface and configure the Ethernet settings.
Define the User Node Parameters, that is, S1-MME interface between the eNodeB node and the SUT
NAS Parameters — Define the NAS Transport parameters that carries UE – MME signalling over the S1 Interface
Select the S1-MME tab and then the NAS Tab.
Select the LTE Version... that will be used by the MME, and the parameters applicable to the version are enabled.
Select the Starting IMSI..., Detach Type, and Detach Mode that uniquely identifies a PDP context. A unique IMSI value is provisioned for each Mobile Subscriber. Configure the Starting IMSI to produce a range of values acceptable to the SUT.
Provision the Starting Access Point Name... to provide a unique APN for each primary PDP context associated with a subscriber. Use the Auto-Increment feature to configure unique APNs.
Check the Location Tracking Information and define the information elements.
Complete the test case by configuring the S1-AP Setup/response time and SCTP protocol source and destination port numbers.
You are now ready to test your configuration. The parameters that have not been addressed control optional behaviors that do not affect the success of a session. Click OK to accept the test case. If any parameters fail validation, you will receive an error indicating the problem parameter. Correct the problem and when the definition is accepted, the test case is listed in the Test Session window.
Run the test session, and a validation check is performed on the test session. This validation ensures that the IP addresses used by the test case do not conflict with any other test sessions that may be running on the test server, and that the test definition does not violate rate and volume limits. You will also receive an error if you attempt to run the test session on a test server that is already running at capacity or is otherwise unable to accept a test session. See Running a Test Session for more information on handling these types of errors.
Select the Reports tab when it becomes available. Ideally, your MN session is established and the Sessions Established, Attempted Session Connects, and Actual Session Connects measurements on the Test Summary tab are all 1. Explore the measurements displayed on the tabs. The measurement definitions are located in the Measurement Reference. Stop the test session when you are ready to continue.
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TROUBLESHOOT: If the MME session fails to connect, Attempted Session Connects will increment but no connections are recorded. Eventually, Session Errors will accumulate as the connection is retried. Common causes of session failures are connectivity problems and authentication failures. Attach Timeout on the NAS tab reports MME connectivity problems. Confirm that the SUT address is correct, and that the address assigned to the MME node does not conflict with another device in the test network. You can also SSH to the test server as cfguser and ping the SUT. If Create Responses are being received, look at the NAS error counters for more information. |
Edit the test case... and set the Activation Rate (Subscribers/sec) and Deactivation Rate (Subscribers/sec) to 10. Set the Mobile Subscribers (Test Configuration tab) to 20 and Maximum Bearers per Subscriber to 5, which will result in 100 total PDP contexts.
Run the test session again. This time you should be able to see the MS sessions establish over 10 seconds (10 PDP contexts each second).
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TROUBLESHOOT: If all of the MS sessions fail to establish, Attempted Session Connects will be larger than Actual Session Connects and Sessions Established. The most likely reason is a problem with parameter values that increment for each MME session:
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Finally, customize the optional behaviors to tailor the test to your purpose.
General options:
You can apply a distribution model to vary the activation and deactivation rates with Advanced Settings... on the Mobile Subscriber pane on the Test Configuration tab.
You can introduce errors in an Ethernet eNodeB node using the Advanced... options on the Control Node sub-tab.
Use separate interfaces for control and bearer plane traffic by enabling a User Node.
After you have finished the definition and successfully tested it, save the test case and the test session as "MME Base" or something similar.
Continue building your standard tests with other test activities or Data Traffic, and then try combining multiple test cases in one test session using linked test cases and Automation Control.