Mobile networks are in the process of transitioning to Long Term Evolution, a Fourth Generation (4G), all packet network architecture. It will permit vastly higher data rates to mobile smart phones, making voice, video, and data truly integrated for the first time - through a single access technology.
In simple terms, LTE consists of a "Packet Core" and a network of eNodeBs (as shown in the figure). eNodeBs have two interfaces, the X2 interface permits eNodeBs to intercommunicate with each other directly, and the S1 interface permits communication with the "Packet Core".
The X2 is the interconnecting interface between two eNodeBs in LTE network and supports both Control Plane and User Plane. The principle Control Plane protocol is X2-AP (X2 Application Protocol) resides on SCTP (Stream Control Transmission Protocol).
LTE X2-AP is responsible for the following functions:
- Mobility Management - this enables the serving eNodeB to move the specified UE responsibility to a target eNodeB.
- Load Management - procedure to report resource status, overload indications and current traffic loading between the eNodeBs
- Reporting of General Error Situations - procedure to report general error situations
- Re-setting /Setting the X2 – procedure to setup or reset X2 interface by exchanging the necessary information between the eNodeBs
- eNodeB Configuration Update - procedure to update the application level data required for the eNodeBs to interoperate in the network.
GL's Message Automation & Protocol Simulation (MAPS™) is a multi-protocol, multi-technology platform used for the emulation of a variety of communication protocols over IP, TDM, and Wireless networks. MAPS™ can be used to test signaling over legacy networks (such as CAS, SS7, ISDN, PPP and more), IP networks (such as SIP, MGCP, MEGACO, SIGTRAN, Diameter…) and also the Wireless technologies including GSM, UMTS, and LTE networks.
GL's MAPS™ designed for X2 Application Protocol (X2-AP) is used to co-ordinate handovers and perform load management between eNodeB (Evolved Node B) network elements - Source eNodeB and Target eNodeB. The MAPS™ X2-AP test tool is designed with specific test cases, as per LTE 3GPP mobile standards.
GL's MAPS™ LTE Conformance Test Suite is designed with 50+ test cases, as per 3GPP TS 36.423 (LTE X2) specifications. It includes inbuilt conformance scripts (*.gls) for multiple eNodeBs in X2 interface as per 3GPP standards. Test cases include general Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 Application Protocol (X2AP) messaging and call flow scenarios over LTE network. Logging and pass/fail results are also reported. Test cases verify conformance of actions such as UE attach/detach, periodic updating, E-RAB setup, X2 setup, Handover procedure, UE context release, and error indication.
MAPS™ LTE X2-AP Interface Emulator supports powerful utilities like Message Editor, Script Editor, and Profile Editor which allow new scenarios to be created or existing scenarios to be modified using messages and parameters.
The application can be integrated within GL’s End-to-End Communications Network Lab (EE-CNL) providing reliable solution to vendors and service providers for simulation, monitoring, and troubleshooting the network using ‘MAPS™ 4G Wireless Lab Suite’.
Possible applications include:
- Simulate up to 500 Smartphones (UEs) powering up and down
- Authenticate and confirm security procedures
- QoS requests for greater or lesser bandwidth
- Temporary addressing management for mobility and security
GL also provides a GUI based LTE Analyzer for on-line capture and decode of the signaling in real-time both during tests and as a stand-alone tracer for live systems.
- Setup a virtual real-time network simulating 4G-LTE network elements using ‘MAPS™ 4G Wireless Lab Suite’
- Simulate two eNodeB elements in LTE X2-AP interface.
- Supports LTE Control plane.
- Generates hundreds of UE Signaling (Load Testing).
- Generates and process X2-AP (valid and invalid) messages.
- Supports Mobility Management, Load Management, Reporting of General Error Situations, Re-setting X2, Setting up the X2, and eNodeB Configuration Update procedures.
- Supports LTE conformance designed with 50+ test cases as per 3GPP TS 36.423 specification
- Insertion of impairments to create invalid messages.
- Customize call flow and message templates using Script and Message Editor.
- Ready-to-use scripts for quick testing.
- Scripted call generation and automated call reception.
- Script based & protocol independent software architecture.
- Provides call statistics and events status.
- Automation, Remote access, and Schedulers to run tests 24/7
Supported Protocols Standards
|Supported Protocols||Standard / Specification Used|
|X2 Application Protocol (X2-AP)||3GPP TS 36423-900|
|Non-Access-Stratum (NAS)||3GPP TS 24.301 V9.0.0 (2009-09)|
LTE X2AP Interface Procedure
Call Generation and Reception
MAPS™ X2 can be configured as Source eNodeB or Target eNodeB terminals in the LTE network over X2 interface handling the above listed UE and Non-UE associated procedures.
While the UE procedures (Mobility Management – Handover, Error Indication) are handled in the Call Generation.
The test is performed to ensure that the MAPS™ X2 configured as Source eNodeB initiates the procedure by sending the HANDOVER REQUEST message to the Target eNodeB. The Target eNodeB (DUT) shall reserve necessary resources, and send the HANDOVER REQUEST ACKNOWLEDGE message back to the Source eNodeB.
The Non-UE procedures (X2AP Setup, Reset request, ENB Configuration Update, and Resource Status request) are automatically handled once the application is started.
As seen in the configuration scenario below, MAPS™ LTE X2 emulator can be configured as Source eNodeB connected to DUT (Target eNodeB). The conformance script can simulate various procedures conforming success/failure test cases and automating the entire Target eNodeB (DUT) testing.
Supported Test Cases
- Handover Test Case
- Handover success
- Handover failure (invalid GTP-TEID, duplicated E-RAB ID)
- Load Indication (send load to and receive load from target eNodeB)
- Error Indication (send error to and receive error from target eNodeB)
- X2 Setup
- X2 Setup Success
- Setup failure and resend setup
- Configuration update
- Send/receive configuration update
- Configure update success after re-send
- Resend Configuration update after failure
- Response Configuration update failure
X2 Setup Success
The below screenshot depicts, MAPS™ LTE S1 Conformance loaded with S1SessionControl.gls conformance script, which ensures that the on initiation of handover procedure from DUT Source eNodeB (UE), MME sends handover request to the Target eNodeB.
Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be ETA or EEA (Octal/Quad Boards), PTA or PEA (tProbe Units), XUT or XUE (Dual PCIe Express) depending upon the hardware.
|Item No.||Item Description|
|PKS141||MAPS™ LTE X2-AP Emulator|
|PKS154||MAPS™ LTE X2 Conformance Test Suite|
|PKS140||MAPS™ LTE S1 Emulator|
|PKS139||MAPS™ Diameter Emulator|
|PKS142||MAPS™ LTE eGTP Emulator|
|PKS146||MAPS™ SGs Interface Emulation|
|GTP Mobile Traffic Options|
Mobile Traffic Core – GTP
Mobile Traffic Core - Gateway
Mobile Traffic Core - Gb