Test and verification of high speed telecom lines
Welcome to the March 2009 issue of GL's consulting newsletter. In this issue, we focus on test and verification of high speed telecom lines before they start carrying commercial, live traffic.
These days telecom networks support a number of applications, including voice, data, and video. The underlying technology may be different - such as TDM, ATM, IP, even Wireless. The physical network can be copper, radio/microwave, optical fiber, or satellite. Service providers must thoroughly evaluate their networks to ensure that their availability meets customer expectations. Such an evaluation would often include testing the networks under normal operating conditions as well as testing beyond normal operational environment, often to a breaking point or close to it, called stress testing. Most operators would prefer to stress test their networks and observe their performance to have a level of confidence before putting through commercial traffic.
Recently, a customer requested GL to test a domestic long distance OC-3 / POS (Packet over SONET) line prior to turn up. We developed a test plan covering throughput testing, continuity testing, and stress testing. Our engineers programmed test equipment to generate traffic with varying packet sizes and inter-packet gaps. Sending smaller packets with minimal gaps stresses network elements that switch packets and also tests any latency issues. Longer packets, scrambling, and octet stuffing and de-stuffing were also tested. An ideal way to generate the maximum stress on circuits under test is to transmit an IP packet which has both a random packet size and gap. Internet traffic may, typically, transmit any of the definable packet sizes and gaps. However, in practice, it is more common to see fewer variations in the packet size as more packets are transmitted. GL's test plan provided a packet stream that closely approximated real life traffic distribution as well as extreme ranges.
Designing and conducting stress tests are specialty areas that are best handled by experts. Our engineers have extensive experience to perform the entire gamut of testing including - design test plans, write test procedures, conduct tests, and document test results. With extensive experience in telecom testing, GL offers a comprehensive suite of testing services to evaluate complex telecom networks. These services are intended to insure that the performance and reliability of networks are completely understood prior to decisions to start carrying live traffic. Our services are very cost efficient and include:
- Testing of high speed telecom networks (T1, E1, T3, E3, OC-3, OC-12, STM-1, STM-4, etc)
- Testing of VOIP, ATM and Central Office switches
- Field testing to verify radio coverage
- Drive testing to verify cellular service coverage
- Assessment/Audio survey of public address systems in transit stations