What is exactly meant by a Loopback on ET ? Why is it done and can anyone suggest any document that explains this in detail ? Has this got anything in specific to do with protocols, What I meant is that, is a loopback necessary when we are working on ISUP et. I would be thankful if someone could provide a clear picture on this. Thanks in advance
funny question 🙂
loopback is used to check the transmission and it is made on “far end”, if after loopback alarms on ET is gone then transmission to the poin where you have made loopback is OK… so loopback should be done on more far point of transmission to find the segment after which alarms doesn’t gone from ET
Loop Break Test is not only useful in ISUP.Normally the PCM itself has some maintanence activty by sending some specific pattern of Bits in SYNC TS-0.By Physically looping…that is Giving the TX out Put to RX Input these BIT Patters returned to the same PCM Maintainer-ET.Which anakyzes the received pattern and says the PCM is WO.If there is any break it wont receive this BITS.So it will say the PCM is NOT OK.
With LOOP BREK You can locate the break in the PCM Link.Local Loop & Remote Loops and Intermediate Loops are possible to test.
Loopback is a key test for ss7 connections. Via the DDF a switch can be configured for Loopback testing. You can check the quality of the circuit. As you install/commission a switch the Loopback test ensures the ss7 connections are working. Once done it provides confidence that you can perform Network signalling (ISUP) to other switches in the production Network.