Nortel DMS-100 Series Maintenance Manual page 97
Subscriber carrier module-100s
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Also See for DMS-100 Series:
- Replacement procedures (1100 pages) ,
- Maintenance manual (762 pages) ,
- Manual (543 pages)
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The A-link is system busied.
The protection link is not switched.
The SMS notes the protection link as having faults. The A-shelf transmit
receive unit serves the A-link and protection link. The protection link is not
switched to the A-shelf.
Note: The SMS can switch the protection link to the A-shelf for a short
time. The switch depends on table CARRMTC datafill for field local carrier
group alarm set filter time (LCGAST) for the primary and protection links.
The switch occurs when table CARRMTC field LCGAST for the protection
link is greater than the LCGAST for the A-link.
Scenario 13
The A-, B- and D-links are in-service. The B-shelf is protection switched
because of a fault on the B-link. The C-link is system busy (SysB) because
of a fault.
The fault on the B-link clears.
The protection link releases from the B-shelf and switches to the SysB
C-link.
The C-link returns to service.
ManB and PBsy primary DS-1 links
Automatic protection switching for the B-, C- or D-shelf cannot occur if the
equivalent DS-1 link is ManB or PBsy. Automatic protection switching can
occur for a ManB or PBsy A-link. Refer to Scenario 1 in this section.
If the RCS requests a protection switch for the A-shelf, the request is
granted. The protection link is switched for the A-shelf. The link state
(INSV, SysB, ManB, or PBsy) does not matter. If a fault occurs at the near
end (SMS) and the A-link is ManB or PBsy, a protection switch does not
occur. If the SMS detects a fault on the A-link before the A-link becomes
ManB or PBsy, the protection link switches to the A-shelf. The SMS scans
for a near end fault or fault clear if the DS-1 link is INSV or SysB. The
SMS is only aware of the DS-1 status before the DS-1 becomes ManB or
PBsy. Refer to scenarios 2 and 3 that follow.
If the RCS detects a fault on a ManB link, other than the A-link, a protection
switch does not occur. If the RCS detects another fault on an INSV link,
other than the A-link, a protection switch does not occur. This action is a
result of RCS protection switching functionality. The SMS handles this
occurrence in a different way. If the SMS detects a fault on a ManB link,
other than the A-link, a protection switch does not occur. If the SMS detects
DMS-100 Family SMS Maintenance Manual XPM10 and up
Maintenance overview 1-81
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Troubleshooting
