ADTRAN Total Access 5000 - Payload Loopback; Loopback Definition; Figure G-1. Line Loopback Diagram; Line Loopback

Total Access 5000 Business Services Deployment Guide
G-2 65K510DEP08-1A
Loopback Definition
AloopbackandBitErrorRateTest(BERT)providetheabilitytoinsertaknowntrafficpattern
andverifytheerror‐freeperformanceofthecircuitatgivenpointsinthesystem.
Line Loopback
Alineloopback(seeFigureG‐1)loopsallofthereceiveddatabacktowardthenetwork(DS3
payloadandDS3data).Thetransmitteddataistheidenticaldatathatisreceivedandisnot
reframedorregenerated.ThistestsrightuptotheDS3interfaceofthemodule.
Theline
loopbackcanbelocaltotheaccessmodule.
Figure G-1. Line Loopback Diagram
Payload Loopback
Apayloadloopback(seeFigureG‐2)performsthesamefunctionalityasthelineloopback,
exceptthepayloadloopbacksendsthereceiveddatathroughtheframer,whereitisreframed
andregenerated,priortobeingtransmittedbackouttowardsthenetwork.Thistestalso
verifiestheinternalhardwareofthe
module.
Thepayloadloopbackislocallyinitiated.
NOTE
TheDS3doesnotsupportapayloadloopback.
DS3 Interface
Framer
Line Loopback
DS-3 Facility