Newsletter: GL Announces Diameter Protocol Emulator for LTE

Welcome to another June 2012 issue of GL Communications' Newsletter providing information and insight into our latest product MAPS™ Diameter Protocol Emulator - Scripted LTE Diameter S6a, S6d, Cx/Dx, Gx, and Rx Interfaces Emulation.

Overview

The Diameter protocol is intended to provide a framework for Authentication, Authorization and Accounting (AAA) for applications such as network access, roaming, and IP mobility. 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 Diameter is a considerably more sophisticated protocol than RADIUS.

Diameter protocol has been chosen as the AAA protocol in all next generation fixed and mobile IP- based networks (IMS, LTE). 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.


Functional Procedure

Message Automation & Protocol Simulation (MAPS™) is GL's general purpose platform for emulation of communication protocols . Recently Diameter protocol for has been added to its wide range of emulation support. Within LTE, MAPS™ can simulate S6a, S6d, Cx/Dx, Gx, and Rx interfaces to test network elements such as the MME (Mobility Management Entity), HSS (Home Subscriber Server), CSCF (Call Session Control Function), SGSN (Serving GPRS Support Node), PDN GW (Packet Data Network Gateway), AF (Application Function) and PCRF (Policy and Charging Rules Function).

The MAPS™ Diameter gives the users the unlimited ability to edit S6a, S6d, Cx/Dx, Gx, and Rx interface messages to support various procedures such as Location Management, Subscriber Data Handling, Authentication, Fault Recovery, and Notification procedures over S6a interface and AA-Request/Answer, Re-Auth-Request/Answer, Abort-Session-Request/Answer, and Session-Termination-Request/Answer procedure over Rx interface.


MAPS™ Diameter Protocol Emulator Specifics

This test tool can be also be used to perform protocol conformance testing as per the following specifications

Supported Protocols Standard / Specification Used
Diameter IETF RFC 3588
S6a & S6d - 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
SCTP RFC 4960

Important Features

  • Emulator can be configured as MME, HSS, PCRF, AF, CSCF, SGSN, and PDN GW entities to emulate S6a, S6d, Cx/ Dx, Gx and Rx interfaces.
  • User-friendly GUI for generating hundreds of UE Signaling (Load Testing)
  • Ready scripts for Location Management, Subscriber Data Handling, Authentication, Fault Recovery, and Notification procedures over S6a interface. AA-Request/Answer, Re-Auth-Request/Answer, Abort-Session-Request/Answer, and Session-Termination-Request/Answer procedure over Rx interface
  • Impairments can be applied to messages to simulate error conditions
  • Supports customization of call flows and message templates using Script editor and Message editor
  • Ready-to-use scripts for quick testing
  • Supports scripted call generation and automated call reception
  • Provides protocol trace with full message decoding, and graphical ladder diagrams of call flow with time stamp
  • Script based & protocol independent software architecture
  • Provides call statistics and associated captured events and error events during call simulation.

Testing HSS and MME in S6a interface

The setup for the message exchange between MME and HSS entities is indicated in the below.

As provided in the figure below, MAPS™ Diameter acts as MME, and tests the DUT that is configured as HSS. MAPS™ Diameter initiates the messages towards HSS and responds to messages from HSS (DUT).

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MAPS™ configured as MME in S6a interface


For HSS testing, scripts are used to ensure that the MAPS™ Diameter acting as MME initiates a call by sending a request message. The response message is received from the DUT (HSS) as seen in the message sequence window below.

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Call Generation at MME Node (S6a Interface)


In MME testing, MAPS™ Diameter is loaded with a set of inbuilt scripts to handle the incoming messages. MAPS™ Diameter acts as HSS and sends response to the incoming message.

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MAPS™ configured as HSS in S6a interface

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Call Reception at HSS Node (S6a interface)

Supported Diameter Procedures in S6a Interface

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  • Location Management Procedures
    • Location Update Procedures: To update location information in the HSS
    • Cancel Location: To delete a subscriber record from the MME or SGSN
    • Purge UE: to indicate that the subscriber's profile has been deleted from the MME or SGSN either by an MMI interaction or automatically
  • Subscriber Data Handling Procedures
    • Insert-Subscriber-Data: for updating and/or requesting certain user data in the MME or SGSN
    • Delete Subscriber Data: to remove some or all data of the HSS user profile stored in the MME or SGSN
  • Authentication Procedures
    • Authentication Information Retrieval: to request Authentication Information from the HSS
  • Fault Recovery Procedure
    • Reset: The Reset Procedure shall be used by the HSS, after a restart, to indicate to the MME and to the SGSN that a failure has occurred
  • Notification Procedure
    • Notification: when an inter MME or SGSN location update does not occur but the HSS needs to be notified

For comprehensive information on the application, please visit MAPS™ Diameter Protocol Emulator web page.


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