Healthy VoIP Nets�Part XLI�Network Management Architectures: Ameritec

Ameritec Corporation, headquartered in Covina, Calif., is a privately held firm engaged in the design, manufacture and sales of telecommunications test equipment. The firm was founded in 1980, and specializes in call generation, transmission testing, and quality of service monitoring.

Ameritec is an ISO 9001:2000 registered company, with its products used by network equipment manufacturers, service providers, and enterprise companies throughout the world—addressing the testing requirements for analog POTS, T1, E1, DS3, OC3/STM-1, MGCP, and SIP circuits.

Ameritec’s test equipment products fall into four general categories:

  • call generation tools
  • local loop testing
  • quality of service (QoS) network monitoring
  • video analysis

The firm’s VoIP network management products are centered in the call generation and network monitoring areas, covering traffic simulation, network stress testing, and performance monitoring tasks.

Ameritec’s primary solutions for traffic simulation and network stress testing are its Allegro and Fortissimo products.
Allegro is a network load generator that simulates subscribers placing calls into the network. The unit gives the user flexibility to serve a wide range of applications associated with switch and network testing, and is ideally suited to allow the user to develop a test environment with the ability to analyze highly complex calls scenarios and interactive applications under load in a dedicated lab environment.

These products allow a developer to create complex call scenarios that can verify new software feature loads or be used for regression testing. Each Allegro is controlled via a PC workstation over a 10/100 MB Ethernet port and utilizes a graphical user interface (GUI) that is intuitive and easy to use.

Three models are available:

  • the Allegro ALG-A, which simulates 2-wire analog loop/ground start subscribers
  • the Allegro ALG-D, which simulates digital T1/E1, Signaling System 7 (SS7), and ISDN Primary Rate Interface (PRI) subscribers
  • the Allegro ALG-IP, which simulates Session Initiation Protocol/Media Gateway Control Protocol (SIP/MGCP) subscribers (see Figure 1).

The Fortissimo products are high volume network traffic devices used to determine how network elements react under extreme call load. The units are designed to test highly complex call scenarios and interactive applications under high call loads, on hundreds of lines simultaneously.

Fortissimo is designed to place calls to or receive calls from other Allegro, Fortissimo or AM3-QoS units to provide a complete test system of call generation and QoS measurements.

A number of Fortissimo models are available, including—

  • the Fortissimo NLG-A, an analog network lode generator that simulates 100 loop start telephony subscribers
  • the Fortissimo NLG-IP, which simulates 192 simultaneous SIP subscribers
  • the Fortissimo NLG-M13 which provides 28 T1 or 21 E1 circuits

Each Fortissimo is also controlled via a PC workstation via an Ethernet port.

Supporting performance and QoS monitoring functions is Ameritec’s system, a comprehensive networking monitoring solution designed to provide detailed QoS and call completion statistics for PSTN and IP networks.

GoldenWatch allows service providers to measure and define metrics of service based on a number of parameters including time of day performance, call volume, call path, and so on. The GoldenWatch program resides on a computer at a central site.

The second part of the system is the responders, which are probe-like units placed in the network to measure QoS performance. These AM3-QoS+ responder units are configured to place calls to other AM3-QoS+ units within the network, and record data. Upon completion of these configuration downloads from the GoldenWatch computer, each responder is then able to execute calling routines that will call other responder units, measure network data such as jitter, lost packets, delay, etc., and later upload this information back to the central site for detailed QoS scoring and reporting.

Alarms are reported by the responder once a QoS threshold value is exceeded, or a specified number of incomplete calls has been reached.

The number of AM3-QoS+ units calling as well as their associated calling intervals can be defined by the user so that comprehensive data can be accumulated to determine QoS and call completion statistics throughout the network.

Statistics compiled for each AM3-QoS include: round trip delays, dropped packets, circuit noise levels, receive levels, signal-to-noise ratios, originated calls attempted and completed, call setup failures, MOS, PESQ and PSQM scores values, call duration, call completion rates, and others.

Further details on the Ameritec architecture and products can be found at Our next tutorial will continue our examination of vendors’ network management architectures.

Copyright Acknowledgement: © 2008 DigiNet Corporation ®, All Rights Reserved

Author’s Biography
Mark A. Miller, P.E., is President of DigiNet Corporation®, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.

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