NFAS backup B

[MitelTim]

Hello,
I’ve been struggling with a 3300 site running NFAS on 2 PRI with a Backup D channel

Normal day to day operation is fine, but if the primary link fails, then both links fail, and the backup D channel doesn’t appear to work..

When there is a failure of the fist link Outgoing calls get “Busy”, and incoming calls get ring no answer. We simulate failure by unplugging the first PRI on the back of the NSU

Shouldn’t NFAS backup work on a complete failure of the 1st PRI?

Here is the IMAT database from the NSU

<Snip>

PRI Link Characteristics
PRI Protocol Protocol Test
logical# Type Variant Call Number Physical Characteristics
--------------------------------------------------------------------------------
1 DMS-100 Invert D Channel: Off
Network Side Interface: Off
Enbloc-only: Off
Disable Fake Answer Supervision: Off
Qsig Channel Numbering: Off
Enable External CLID Replacement: Off
NFAS Master
NFAS Interface: 0
NFAS Group: 0
Line Coding=B8ZS
Framing=ESF
Line Build Out=0 dB
Invert Data=Disable
Comment ""
2 DMS-100 Invert D Channel: Off
Network Side Interface: Off
Enbloc-only: Off
Disable Fake Answer Supervision: Off
Qsig Channel Numbering: Off
Enable External CLID Replacement: Off
D-Channel Backup
NFAS Interface: 1
NFAS Group: 0
Line Coding=B8ZS
Framing=ESF
Line Build Out=0 dB
Invert Data=Disable
Comment ""


</Snip>