Nortel Networks 1000 - Manual (Page 306)

306 NT5D33 and NT5D34 Lineside E1 Interface cards
Figure 77
MMI Local loopback test
Test 2, external loopback, applies an external loopback to the E1 link. Test
data is generated and received by the LEI on all timeslots. If test 1 passes
but test 2 fails, it indicates that the E1 link is defective between the LEI and
the external loopback location. If test 1 was not run and test 2 fails, the
E1 link or the LEI could be defective. To isolate the failure to the E1 link,
tests 1 and 2 must be run in tandem.
Figure 78 "MMI External loopback
test" (page 306) demonstrates how an external loopback is applied to the
E1 link.
Figure 78
MMI External loopback test
Test 3, network loopback, loops the LEI’s received E1 data back toward
the CPE. No test data is generated or received by the LEI. If test 2 passes
but test 3 fails, it indicates that the CPE device is defective. If test 2 was
not run and test 3 fails, the E1 link or the CPE device could be defective.
To isolate the failure to the CPE device, tests 2 and 3 must be run in
tandem.
Figure 79 "MMI Network loopback test" (page 307) illustrates how
the signaling is looped back toward the CPE.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.