19-07-2012, 04:13 PM
Verification of Bidirectional path Switched Ring Protection
Verification of Bidirectional .doc (Size: 715 KB / Downloads: 30)
SDH Analyser is connected to stream number 1of ADM1 station A terminated in the DDF.At station B DDF stream number1 is given a local loop by connecting the receiver to this transmit port using a PCM patch cord using this software of the system stream number1 is cross connected with a normal path 1 direction and path in path2 direction.
Inside the SDH Analyser , settings are done for measuring the automatic protection switching timing of the stream.
Verified and found the 2Mbps stream taken out from the SDH Analyser and fed to DDF A Station in getting a perfect loop back in the meter via the normal path.
Start Automatic protection switching time measurement of SDH analyser In its recommendation ITU-T G.841 the International Telecommunications Union has specified a maximum time allowed for SDH or SONET networks to switch to backup circuits (APS disruption time). Network managers must test the resilience of their networks in order to test if they comply with the ITU-T recommendations. Disconnect the transmit fiber in the FDF 1.so that the stream automatically switch over to the protection path.
Step3
View the protection time of stream in this meter.
Time obtained 42 millisecond.
42ms <50ms (standard time for Automatic Protection Switching )
Conclusion.
The present day long – distance transmission systems are mainly optical fiber transmission systems. In BSNL also the long-distance transmission systems are mainly optical fiber transmission systems. The present day scenario is that both PDH and SDH systems are jointly working in BSNL network. However, the backbone networks are occupied by the SDH systems.
In the present study we have studied the designing of SDH optical fiber link , its testing as per ITU-T guidelines and the formation of SSH 2 fibre ring using the state of the art technology to provide protection switching with the aim of providing uninterrupted service even after route failure. Also as a part of link design, I have studied splicing and testing of optical fibre cable using both 1310nm and 1550 nm windows as per BSNL standard.
Thus as a telecommunication engineer this project work helped me to study the splicing and testing of optical fibre as per ITU standards. Also I gained experience in designing an SDH , 2 fiber ring and measured the system performance as per ITU guide lines. Also through this project work I got experience in connecting E1s from SDH to different Telephone Exchanges. Thus practical experiences and knowledge that I gained in designing optical fiber long-distance transmission system was highly useful and inevitable to any engineer working in the telecommunication sector. In this sense this project work was very much useful.
It is concluded that the designed bidirectional path switched ring of STM1 ADM consisting of 50km between them is protecting the 2.048Mbps (PCM) tributary with a protection switching time <50ms as per the standards prescribed.