Wireless 4G Core Network

IP Network Simulation

MAPS™ Diameter Protocol Emulator

Simulation of Diameter protocol for S6a, S13, s13’, Cx/Dx, Gx, Rx, SLg, SLh, Sh and Gy interfaces supporting Authentication, Authorization and Accounting (AAA) framework for all next generation fixed and mobile IP- based networks (IMS, LTE).



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 Center (GMLC) acting as the server providing information to External LCS Clients.


MAPS™ Diameter can simulate S6a, S13, s13’, Cx/Dx, Gx, Gy, Rx, SLg, Sh, 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 signaling 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, Sh, 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 Signaling Path Status, Access Network Charging Information Notification, Reporting Access Network Information, and Provisioning of AF Signaling 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
TLS RFC 5246

S6a Interface

The S6a interface enables the transfer of subscriber related data between the MME and the HSS

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

MAPS™ Diameter Supporting S6a Interface Procedures
(Authentication, Location Update, Notification, Faulty Recovery Procedures)

Call Generation at MME Node (S6a Interface)

Call Reception at HSS Node (S6a interface)

Rx/Gx Interface

The following illustrates the Authentication Authorization (AA) procedure in Diameter Rx interface and Gx interface:

MAPS™ Diameter Supporting Rx Interface Procedures
(Authentication, Authorization - AA Procedures)

The MAPS™ Diameter simulates 3GPP AAA (Authentication Authorization Procedure) call control messages between the AF and PCRF nodes. Supported procedures in Rx interface are - AA-Request/Answer, Re-Auth-Request/Answer, Abort-Session-Request/Answer, Session-Termination-Request/Answer, Subscription to Notification of Signaling Path Status, Access Network Charging Information Notification, Reporting Access Network Information, and Provisioning of AF Signaling Flow Information.

Call Generation (Rx Interface)

Call Reception (Rx Interface)

S13/S13' Interface

The following illustrates the ME (Mobile Equipment) Identity Check procedure in Diameter S13 interface:

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/S13' Interface Procedure

S13 Interface Node Simulation

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.

MAPS™ Diameter as CTF and OCS

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™ 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

SLh Interface (LoCation Service)

The following call flow illustrates the Location Service Routing Info procedure over Diameter based SLh interface between GMLC and HSS entities:

Location Service Routing Info Procedure

MAPS™ Diameter configured as GMLC (Gateway Mobile Location Center) which initiates the procedure to retrieve routing information for LCS of a specified user from HSS.

LCS Routing Procedure for SLh interface

MAPS™ Diameter configured as HSS (Home Subscriber Server) responds with the correct MME identity for the subscriber specified.

Call Reception for SLh interface

SLg Interface (LoCation Service)

The following call flow illustrates the Provide Subscriber Location and Subscriber Location Report procedures over Diameter based SLg interface between GMLC and MME entities:

  • Provide Subscriber Location - The Provide Subscriber Location operation is used by GMLC to request the location of a target UE from the MME
  • Subscriber Location Report - Subscriber Location Report operation is used by MME or SGSN to provide the location of a target UE to GMLC when a request for location has been implicitly issued.

MAPS™ Diameter configured as GMLC (Gateway Mobile Location Center) which initiates the procedure requesting MME to provide subscriber location information of the targeted UE.

Provide Location Info Procedure for SLg interface

MAPS™ Diameter configured as MME (Mobile Management Entity) upon reception of the request, performs authentication privacy verification and retrieves the location information of the target UE from E-UTRAN according to the procedure.

Call Reception for SLg interface

Sh interface

Method of communication between the AS (Application Server) function and the HSS (Home Subscriber Server), AS uses the Sh interface in two basic ways:

  • To query or update a user's data stored on the HSS
  • To subscribe to and receive notifications when a user's data changes on the HSS

The following illustrates the procedure in Diameter Sh interface:

Application is requested for user data In this case, the AS (Application Server) sends a message to the HSS requesting data for a certain user.

Application receives subscription to user data In this case, the AS (Application Server) service subscribers in HSS to receive notifications of changes in user profile data. Once the subscription is established, the HSS will be notified.

Call Generation - Sh Interface

Call Reception - Sh Interface

CxDx Interface

The Diameter Cx and Dx interfaces are the reference points for interactions between Home Subscriber Server (HSS) and Interrogating Call Session Control Function (I-CSCF) or Serving Call Session Control Function (S-CSCF).

Serving-CSCF (S-CSCF) is always located in the home network. It is the central node of the signaling plane and performs session control as well. S-CSCF uses Diameter Cx and Dx interfaces to the HSS to download and upload user profiles, it has no local storage of the user. All requisite information will be loaded from the HSS.

Interrogating-CSCF (I-CSCF) is an another function located at the edge of an administrative domain. I-CSCF queries the HSS using the Diameter Cx interface to retrieve the user location and then routes the SIP request to its assigned S-CSCF.

Server-Assignment-Request (SAR): The Diameter client in a SIP server sends Server-Assignment-Request command to the Diameter server to indicate the completion of the authentication process and to request that the Diameter server store the URI of the SIP server that is currently serving the user. The main functions of the Diameter SAR command are to inform the Diameter server of the URI of the SIP server allocated to the user, and to store or clear it from the Diameter server.

Server-Assignment-Answer (SAA): The Diameter server sends Server Assignment Answer command in response to a previously received Diameter Server-Assignment-Request (SAR) command. The response may include the user profile or part of it, if requested.

User-Authentication-Request (UAR): The Diameter client in a SIP server sends User Authentication Request command to the Diameter server to request authorization for the SIP User Agent to route a SIP REGISTER request. Because the SIP REGISTER request implicitly carries a permission to bind an AOR to a contact address, the Diameter client uses the Diameter UAR as a first authorization request towards the Diameter server to authorize the registration.

User-Authentication-Answer (UAA): The Diameter server sends User-Authentication-Answer command in response to a previously received Diameter User-Authorization-Request (UAR) command. The Diameter server indicates the result of the requested registration authorization.

Call Generation - CxDx Interface

Call Reception - CxDx Interface


Item No. Description
PKS140 MAPS™ LTE S1 Emulator
PKS139 MAPS™ Diameter Emulator
PKS141 MAPS™ LTE X2-AP Emulator
PKS142 MAPS™ LTE eGTP Emulator
PKS146 MAPS™ SGs Interface Emulation
  GTP Mobile Traffic Options
ETH101Mobile Traffic Core – GTP
ETH102Mobile Traffic Core - Gateway
ETH103Mobile Traffic Core - Gb Interface

Item No. MAPS™ for Wireless Network
PKS140 MAPS™ LTE S1 Emulator
PKS142 MAPS™ LTE eGTP (S3, S4, S5, S8, S10, S11 & S16) Emulator
PKS141 MAPS™ LTE X2 AP Emulator
 Item No. MAPS™ for IP Network
MAPS™ MEGACO Conformance Test Suite (Test Scripts)
PKS124 MAPS™ MGCP Protocol Emulation with Conformance Test Suite
 Item No. RTP Traffic Options
PKS102 RTP Soft Core (additional)
PKS103 RTP IuUP Softcore
RTP Pass Through Fax Emulation
Fax Port Licences - 2 Fax Ports, RO
Fax Port Licences - 8 Fax Ports, RO
Fax Port Licences - 30 Fax Ports, RO
Fax Port Licences - 60 Fax Ports, RO
Fax Port Licences - 120 Fax Ports, RO
PKS211 T.38 Fax Simulation
PKS108 RTP Voice Quality Measurements
PKS109 MAPS™ High Density RTP Generator
PKS111 MAPS™ Remote Controller
PKS170 CLI Support for MAPS™
PKS106 RTP Video Traffic Generation
PCD103 Optional Codec – AMR – Narrowband (requires additional license)
PCD104 Optional Codec - EVRC (requires additional license)
PCD105 Optional Codec – EVRC-B (requires additional license)
PCD106 Optional Codec – EVRC-C (requires additional license)
PCD107 Optional Codec – AMR - Wideband (requires additional license)
PCD108 Optional Codec  - EVS (requires additional license)
PCD109 Optional Codec  - Opus (requires additional license)
Item No. Related Software
XX120 SS7 Analyzer Software
OLV120 Offline/ Remote SS7 Analyzer Software
XX100 ISDN Analyzer Software
OLV100 Offline/ Remote ISDN Analyzer Software
XX150 T1 or E1 Real-time GSM Protocol Analyzer
OLV150 Offline T1 or E1 GSM Protocol Analyzer
XX165 T1 or E1 Real-time UMTS Protocol Analyzer
PKV100 PacketScan™ (Online and Offline)
PKV120 PacketScan™ HD w/4 x 1GigE
PKV120p PacketScan HD™ w/4 x 1GigE - Portable
PKV122 PacketScan™ HD w/2 x 10GigE
PKV122p PacketScan HD™ w/2 x 10 GigE - Portable