MAPS™
Diameter Protocol Emulator
(Diameter Interfaces Emulation)
Background
The Diameter protocol is intended to provide a framework for Authentication, Authorization and Accounting (AAA) applications such as network access, roaming, and IP mobility. The AAA protocols are used to determine whether the user is allowed to connect to the network (Authentication) and use a particular service (Authorization). It is also used to track network resources used by end-user for accurate billing (Accounting).
AAA protocols such as TACACS and RADIUS were initially deployed to provide dial-up PPP and terminal server access. Over time, with the growth of the Internet and the introduction of new access technologies, including wireless, DSL, Mobile IP and Ethernet, routers and network access servers (NAS) have increased in complexity and density, putting new demands on AAA protocols. As a result, the Diameter protocol has been chosen as the AAA protocol in all next generation fixed and mobile IP- based networks (IMS, LTE). The Diameter protocol is a considerably more sophisticated protocol for mobility management, policy and charging (online and offline) control. It is designed to support data, services, and applications with extreme flexibility and is expected to replace all legacy protocols such as MAP, LDAP, Radius, and others.
LTE Diameter network also includes LCS (LoCation Services) specific elements and entities, their functionalities, interfaces, as well as communication messages, necessary to implement the positioning functionality in a cellular network. LoCation Services (LCS) architecture follows a client/server model with the gateway mobile location centre (GMLC) acting as the server providing information to External LCS Clients.
Overview
MAPS™ Diameter can simulate S6a, , S13, s13’, Cx/Dx, Gx, Gy,Rx, SLg, SLh and Gy interfaces and LTE IMS network elements such as the MME (Mobility Management Entity), HSS (Home Subscriber Server), AF (Application Function), PCRF (Policy and Charging Rules Function), CSCF (Call Session Control Function), SGSN (Serving GPRS Support Node), PCEF (Policy and Charging Enforcement Function), EIR (Equipment Identity Register), PDN GW (Packet Data Network Gateway), AS (Application Server), CTF (Charging Trigger Function), and OCS (Online Charging System).
MAPS™ Diameter is enhanced to simulate Location Service (LCS) based SLh and SLg interfaces between the GMLC <-> HSS and GMLC <->MME defined for the Control Plane as per 3GPP TS 23.271 specifications.
The application is available as -
- MAPS™ Diameter (Item # PKS139) for S6a, S13, S13', Cx/Dx, Gx, Rx, Sh, Gy, SLh, and SLg interfaces
Other interfaces such as Rf, Dh, Gq, Zh, Zn, Wa, Wd, Wx, Wm, Wg, Pr will also be supported by the application in near future.
The application supports both SCTP (Stream Control Transmission) and TCP (Transmission Control Protocol) transport protocol layers for PSTN signalling messages over IP networks. MAPS™ Diameter also supports TCP/TLS (Transport Layer Security) for the secured information transfer.
- MAPS™ Diameter Emulator includes powerful utilities like Message Editor, Script Editor, and Profile Editor which allow new scenarios to be created or existing scenarios to be modified using Diameter messages and parameters. "Message sequences" are generated through scripts. "Messages" are created using message templates. These features give the users the unlimited ability to edit messages on supported interfaces to support various procedures listed below.
MAPS™ also supports an End-to-End 4G LTE Communications Network Lab with all components to simulate E-UTRAN, EPC (Evolved Packet Core) and IMS, allowing complete testing of the LTE-IMS network.
Possible applications include:
- Simulate up to thousands of Smartphones (UEs) powering up and down
- Authenticate and confirm security procedures
- Temporary addressing management for mobility and security
- Real-time applications of location-based services such as up-to-date information for vehicle tracking, stolen assets tracking, temperature, traffic services, emergency services, etc.
GL also provides a GUI based All-IP PacketScan Analyzer for on-line capture and decode of the Diameter signaling in real-time both during tests and as a stand-alone tracer for live systems.
Main Features
- Supports simulation of real-time LTE network using “MAPS 4G Wireless Lab Suite”.
- Emulator can be configured as MME, HSS, PCRF, PCEF, CSCF, SGSN, PDN GW, EIR, AF, AS, CTF and OCS entities to emulate S6a, S13, S13’, Cx/Dx, Gx, Rx, SLg, SLh, and Gy interfaces.
- Supports simulation of Location Services (LCS) based SLh and SLg interfaces between the GMLC <-> HSS and GMLC <->MME entities.
- User-friendly GUI for generating hundreds of UE Signaling (Load Testing) over SCTP/TCP Layers.
- Support for TCP/TLS for secured information transfer
- Ready scripts for procedures over interfaces such as -
- Procedures over S6a interface
- Location Management, Subscriber Data Handling, Authentication, Fault Recovery, and Notification
- Procedures over Rx interface
- AA-Request/Answer, Re-Auth-Request/Answer, Abort-Session-Request/Answer, and Session-Termination-Request/Answer, Subscription to Notification of Signalling Path Status, Access Network Charging Information Notification, Reporting Access Network Information, and Provisioning of AF Signalling Flow Information
- Procedure over Gx interface
- IPCAN Session Establishment and Modification
- Procedure over S13, and S13' interface
- ME (Mobile Equipment) Identity Check procedure
- Procedure over Gy interface
- Immediate Event Charging (IEC), Event Charging with Unit Reservation (ECUR), Session Charging with Unit Reservation (SCUR)
- CC-Request/Answer, Re-Auth-Request/Answer Procedures
- Procedure over SLh, SLg interfaces
- Location Request/Response
- Emergency Location Request/Response
- Repeated Location Report
Supported Protocols Standards
Diameter Protocol Stack |
Supported Protocols |
Standard / Specification Used |
| Diameter |
IETF RFC 3588
S6a, S6d, S13 - 3GPP TS 29.272 V10.3.0
Rx - 3GGP TS 29214-b10
Cx/Dx - 3GPP TS 29.228 & TS29.229
Gx - 3GPP TS 29.212 & TS 23.203
Sh - 3GGP TS 29.328 & TS 29.329
Gy/Ro (DCCA)- 3GGP TS 32.225, 3GPP TS 32.299 and IETFRFC 4006
SLg - 3GPP TS 29.172
SLh - 3GPP TS 29.173 |
| SCTP |
RFC 4960 |
| TCP |
RFC793 |
| TLS |
RFC 5246 |
S6a Interface
The S6a interface enables the transfer of subscriber related data between the MME and the HSS
MAPS™ Diameter Supporting S6a Interface Procedures
(Authentication, Location Update, Notification, Faulty Recovery Procedures)
MAPS™ Diameter at the MME end initiates the following S6a interface procedures:
- initiates the Authentication procedure by sending Authentication-Information-Request message
- initiates the Update Location procedure by sending Update-Location-Request message
- initiates the Purge UE procedure by sending Purge-UE-Request message
Call Generation at MME Node (S6a Interface) |
Call Reception at HSS Node (S6a interface) |
S13/S13’ Interface
The following illustrates the ME (Mobile Equipment) Identity Check procedure in Diameter S13 interface:
S13/S13' Interface Procedure
The Mobile Equipment Identity Check Procedure is used between the MME and the EIR to check the Mobile Equipment's identity status (e.g. to check that it has not been stolen, or, to verify that it does not have faults).
This procedure is mapped to the following commands in the Diameter application -
- ME-Identity-Check-Request (ECR) Command
- ME-Identity-Check-Answer (ECA) Command
S13 Interface Node Simulation
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Call Reception S13’ Interface |
Call Generation S13’ interface |
Testing CTF and OCS in Gy/Ro interface
Both Gy and Ro interfaces define procedures for online charging in IMS & LTE networks. Ro interface is between IMS entity (CSCF) and Online Charging System (OCS) & Gy interface is between the PCEF (e.g., PDN GW) and the OCS.
The PCEF node in LTE network, and CSCF node in IMS network perform the role of a Charging Trigger Function (CTF) entity to issue charging events to an Online Charging System (OCS). The charging events can be immediate (IEC), event-based (ECUR), or session-based (SCUR). An Online Charging System (OCS), is a functional architecture that provides support for all three levels (service level, subsystem level, and bearer level) of online charging as depicted in the image below.
As provided in the figure below, MAPS™ Diameter can be configured as CTF or OCS, while the other acting as the DUT in the network. If MAPS™ Diameter is configured as CTF, it tests the DUT (OCS) by initiating the messages towards OCS.
Similarly, if MAPS™ Diameter is configured as OCS, it tests the DUT (CTF) by receiving the requests from CTF and sending responses back to the CTF (DUT).
MAPS™ Diameter as CTF and OCS
MAPS™ configured as CTF in GY/RO interface (Session Based Charging)
Session Based Charging is a credit-control process that makes use of several interrogations: the first (INITIAL_REQUEST), a possible intermediate (UPDATE_REQUEST), and the final (TERMINATION_REQUEST). The first interrogation is used to reserve money from the user’s account and to initiate the process. The intermediate interrogations may be needed to request new quota while the service is being rendered. The final interrogation is used to exit the process.
The MAPS™ Diameter as CTF initiates a call by sending a CCR (Credit Control Request) message to the test the OCS. The CCA (Credit Control Answer) response message received back from the DUT (OCS) can be verified as shown in the message sequence window below.
Diameter Gy/Ro Interface Session based Charging Procedure |
Call Generation Diameter DCCA Interface for Session Based Charging |
MAPS™ configured as OCS in GY/Ro interface (Event Based Charging)
Event Based Charging is a one-time event process used when there is no need to maintain any state in the Diameter credit-control server; for example, enquiring about the price of the service. The use of a one-time event implies that the user has been authenticated and authorized beforehand.
In CTF testing, MAPS™ Diameter is loaded with a set of inbuilt scripts to handle the incoming messages. MAPS™ Diameter acts as OCS and sends response to the one-time event based charging request as shown in the message sequence window below.
Diameter Gy/Ro Interface Session based Charging Procedure |
Call Generation Diameter DCCA Interface for Session Based Charging |
Buyer's Guide 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), UTA or UEA (USB Units), HUT or HUE (Universal Cards), and HDT or HDE (HD cards) depending upon the hardware.
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