Issue TOC Print full article Print this page Download as PDF E-Mail this URL Flame the author     In this article Introduction Product Details Good Looks, Too Executive Summary How We Tested Sneak Peek ETM 4.0 Calling ROI

The ETM system comprised three rackmounted Dell Windows 2000 servers and a pair of rackmounted ETM hardware appliances, connected by a private 100-Mbps Ethernet switch. We used a 1-GHz Intel Celeron processor with 1 GB of RAM to run the ETM client software: TeleView Infrastructure Manager 3.0.3 and TeleAudit Usage Manager 3.0.3. Another 1-GHz Celeron processor with 1 GB of RAM accommodated the ETM Management Server 3.0.3 and TeleAudit Report Server 3.0.3 software. And finally, a 1.13-GHz Intel Pentium III box with 1 GB of SDRAM (Synchronous DRAM) and three 18-GB drives under a hardware RAID 5 controller housed the Oracle 9i Database Server.

We tested the ETM platform using both an existing PRI span connected to an NEC PBX and a simulated PRI span looped through a Spirent Communications Abacus call generator. In the PRI runs, we tested inbound and outbound calls using POTS lines, PCS (Personal Communications Services) and GSM (Global System for Mobile Communications) service (U.S. and European spec), fax, analog modem and voice/fax combination equipment. Both domestic and international calls were logged, monitored and/or terminated. The Abacus simulated heavy volume closed-loop traffic of a variety of call types.

We configured one ETM Communication Appliance (Model 3200) to support 16 North American ISDN-PRI spans, and a second ETM appliance (Model 1010) to support four analog circuit ports. The appliances run customized versions of Linux.

Counting on Abacus

We would not have been able to thoroughly test the ETM without the generous loan from Spirent of an Abacus Test System. After sorting out our initial configuration and settings (somewhat challenging as we were setting up a closed-loop test environment), we hammered the ETM with hundreds of thousands of simulated calls from the Abacus in the course of a month.

We configured two ISDN PRI cards (mapping 23 "extensions" each) in the Abacus, one to receive "incoming" calls and one to generate our "outbound" calls, yielding 10-digit source and destination numbers for testing. We used a staggered test-dialing cycle (Extension 1 direct-dials Extension 24, makes connection, keeps line open as a voice call for 35 seconds, then disconnects. Keep going through Extension 23 dialing Extension 46, repeat ad infinitum).

Note that we did not connect the Abacus to our production PBX; this was a standalone test environment that placed the ETM equipment in-line between the two Abacus cards.

We were consistently impressed with the quality and capabilities of the Spirent equipment. The Abacus is the most capable piece of telco testing equipment that our team has worked with, functioning as both a call-load generator and central office emulator. The test system is able to generate a mix of tones, real speech, fax, data or PRBS, while supporting (take a deep breath): analog, T1 CAS (channel associated signaling), E1 CAS, GR-303, SLC-96, V5.1, V5.2, SS7, ISDN PRI on T1, ISDN PRI on E1, ISDN BRA (basic rate access) over U-interface, and ISDN BRA over S-interfaces, with the ability to generate five to 1,023 channels, depending on configuration.

This is a rackmount chassis system that can be configured with from one to 40 cards. Minimum system configurations start at about $10,000; Spirent says the average cost works out to about $200 per port.