Carriers and enterprises are migrating to IP Networks from traditional PSTN Networks because IP Networks provide substantial advantages -- such as voice, data, and video convergence, greater platform densities, rapid service and feature enhancements, and productivity gains from unified communications. However, the transition to all IP requires “Gateways” that convert legacy signaling and traffic carried over TDM to new IP signaling / traffic carried over IP/Ethernet - therefore the need to test and emulate elements within both.

GL’s MAPS™ (Message Automation and Protocol Simulation) platforms can be used to simulate various elements in a hybrid TDM VoIP network, and test interconnection of different networks, be it IP-IP, TDM-IP, or TDM-TDM. A typical depiction of a hybrid TDM/IP network, and its components simulated by MAPS™ is shown in the figure above.  

SS7 signaling in the PSTN is translated to SIGTRAN by the Signaling Gateway (SG).  TDM traffic is repackaged into RTP packets by the Media Gateway (MG).  A Media Gateway Controller (MGC) controls the various elements within the IP Network using SIP, Megaco, and MGCP protocols.  The reverse may happen if the call is destined to PSTN.  If the call stays within the IP domain, then an IP PBX may route the call to an IP endpoint.

MAPS™ can completely simulate and test Signaling Gateways, Media Gateways, Media Gateway Controller and SIP servers or SIP end points. Complex scenarios can be easily setup to perform end-to-end testing supporting SS7-to-SS7 (same SSP), SS7-to-SS7 (different SSP's), and SS7-to-SIP via soft switch.

A typical MAPS™ platform simulating a Signaling Gateway may consist of high density T1 E1 Cards, a Gigabit Ethernet Card, a multiprocessor CPU (such as an i7 PC) and MAPS™ SIGTRAN and MAPS™ SS7 software. Pre-written scripts translate SS7 to Sigtran and vice a versa. Media Gateways can be similarly integrated using MAPS™ software products, for Media Gateways high density T1 E1 Cards and MAPS™ Megaco or MAPS™ MGCP is required. Similarly, MAPS™ can assume the role of any of the elements.

Gateway between VoIP and Legacy PSTN

Key Facts

• Single or Multi-Interface Tester for Wireless and Wired Networks
• Multi-technology (LTE, UMTS, GSM and GPRS) support
• An end-to-end testing of call control and QoS from TDM-to-TDM, TDM-IP–TDM, or an All-IP network
• Provides an advanced full-fledged 2G, 3G, and 4G Network Environment for test purposes
• Automation, Remote access, and Schedulers to run tests 24/7
• Widest array of protocol analysis tools to capture and post troubleshooting

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Test and Verification of TDM / VoIP Network Elements Using MAPS™

The following are some of the GL's products that provide testing and emulation of Media and Signaling Gateways and Media Gateway Controllers:

• TDM Call Generation (SS7, ISDN, CAS) - Hundreds to thousands of calls can be generated by MAPS™ SS7, MAPS™ ISDN, or MAPS™ CAS elements. This includes TDM traffic such as voice and fax over T1 E1 and ISUP signaling per ITU-T, ANSI, ETSI and CHINA standards. ISDN and CAS are also supported.
  
• SS7 to SIGTRAN Gateway Emulation - MAPS™ SIGTRAN and MAPS™ SS7 can be combined into one entity to emulate a complete Signaling Gateway. M3UA, M2UA, and M2PA modes are easily supported.
  
• Media Gateway Emulation – MAPS™ MEGACO or MAPS™ MGCP can be configured with T1 E1 trunks to simulate a Trunking Media Gateway. Megaco signaling to/from a Media Gateway Controller is used to establish TDM to RTP connections and vice versa. Codec support is provided for common G.711 ULAW, G.711 ALAW, G.729, G.729B and many more. Fax is also supported.
  
• Media Gateway Controller Emulation – MAPS™ MEGACO, MAPS™ SIP, MAPS™ MGCP, and MAPS™ SIGTRAN can be combined to perform Media Gateway Controller functions - interacting with multiple Media Gateways and multiple Signaling Gateways and as a SIP server as well. Scripts can be written to route calls to different Service Switching Point's and SIP users based on area codes.
  
• Signaling and Traffic Analysis - PacketScan™ - an All-IP Analyzer can be configured on a remote system for capturing all signaling - SIGTRAN, MEGACO, SIP and RTP Traffic in real-time.
• Signaling and Traffic Analysis – An SS7 Analyzer can be configured on a remote system for capturing all SS7 signaling and bearer traffic.

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Scenario: TDM-to-IP Simulation

This scenario allows placing call using external SIP user to MAPS™ SS7, the signaling goes through MGC Simulator, and bearer goes through a real Media Gateway.

• Softswitch SIP user sends signaling traffic over SIP to MGC Simulator
• MGC Simulator sends signaling traffic over SIGTRAN to real MGW
• Real MG sends SS7 to SS7 Call Simulator
• MGC Simulator sets up bearer channel in real MG over Megaco
• SS7 Call Simulator sends TDM bearer traffic to real MGW
• Real MG sends RTP bearer traffic back to Softswitch SIP user to simulate voice call

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Scenario: TDM-to-TDM Loopback Simulation (Same SSP)

This scenario allows placing call using SS7 Call Simulator back to itself, with signaling traversing through MGC Simulator, and bearer through MG Simulator.

• SS7 Call Simulator sends signaling traffic out SS7 link to SG Simulator (on MGC Simulator system)
• MGC Simulator sets up bearer channel with real MG /Simulated MG using Megaco
• SS7 Call Simulator sends TDM bearer traffic to MG Simulator on one channel, real MG / Simulated MG forwards back on a different channel to simulate voice call

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Scenario: TDM-to-TDM Loopback Simulation (Different SSPs connected to different Signaling Gateways)

This scenario allows placing call using SS7 Call Simulator back to itself, signaling goes through MGC Simulator, and bearer goes through a real Media Gateway to Media Gateway Simulator.

• SS7 Call Simulator sends signaling traffic out SS7 link to SG Simulator (on MGC Simulator)
• MGC Simulator sets up bearer channel with real MG using Megaco
• MGC Simulator sets up bearer channel with MG Simulator using Megaco
• SS7 Call Simulator sends TDM bearer traffic to real MGW
• Real MG sends bearer traffic to MG Simulator over RTP
• MG Simulator sends bearer traffic back to SS7 Call Simulator to simulate voice call

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