SONET/SDH Network Installation and Maintenance

In recent years, there have been many technological advances that have changed the work environment of transport engineers and technicians. These include packet-aware SONET/SDH add/drop multiplexers (ADMs, also known as multiservice provisioning platforms (MSPPs) or multiservice transport platforms (MSTPs and reconfigurable optical add/drop multiplexers (ROADMs), which are being deployed as an integrated part of the optical transport network (OTN). This network evolution is making testing and qualification of these transport networks during the installation and commissioning very crucial.

Network installation and maintenance routines include continuity testing to ensure that end-to-end connectivity is established and that the logical setup is correct. It also includes long-term BERT tests to ensure the stability of the network and to verify its ability to operate error-free for an extended time of period. These testing routines, especially when performed without the proper test equipment, can prove complex and cumbersome to perform.

Recommended Tests and Equipment

The SONET/SDH Transport Blazer offers field technicians all the critical test functions required to install and maintain SONET/SDH and next-generation networks.

Transport Blazer modules can be housed in two portable platforms:


FTB-200 Compact Platform A modular portable test set for the network technician	FTB-400 Universal Test System The ultimate multiple-module platform for network experts involved in optical and protocol testing	FTB-8120/8130 Transport Blazer modules

Test Method	Description	Recommended Equipment
Power-level verification	This test is about testing ingress and egress power levels without risking damage to expensive circuit packs or SONET/SDH test equipment.	Options for the Next-Generation SONET/SDH Test ModulesFTB-8120NG/FTB-8130NG Transport Blazer
Frequency-offset testing	Frequency accuracy verification of the SONET/SDH line rate is a good sanity check prior to BER testing.
Continuity testing	This test ensures that end-to-end connectivity is established and that the logical setup is correct.	Next-Generation SONET/SDH Test Modules—FTB-8120NG/FTB-8130NG Transport Blazer
Stress testing/margin verification	Stress testing is important to verify that the engineered loss margin is as expected.	Next-Generation SONET/SDH Test Modules—FTB-8120NG/FTB-8130NG Transport Blazer and FVA-60B Variable Attenuator
Automatic protection switching (APS)	APS measurement verifies that the transport system meets the 50 ms switching time specified by the ITU G.841 standard in the case of a fiber cut or circuit pack failure.	Next-Generation SONET/SDH Test Modules—FTB-8120NG/FTB-8130NG Transport Blazer
Round-trip delay (RTD) measurement	RTD test ensures that cellular and IP traffic (i.e., video and voice) are not experiencing any delay due to traveling distance.
Long-term bit-error-rate (BER) testing	The bit-error-rate (BER) test provides a complete qualification of the payload-carrying ability of the SONET/SDH circuit.