Nortel Networks 3500 User Manual
2-118 Operation, administration, and maintenance (OAM) features
OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Protection switching
At the OC-48 line rate, an optical fiber cut could result in 1344 VT1.5s being
switched to an alternate path. The system is required to meet the 60-ms switch
time for multiple path failures on a single optical interface only.
switched to an alternate path. The system is required to meet the 60-ms switch
time for multiple path failures on a single optical interface only.
For more information about protection switching behaviour for specific circuit
packs:
packs:
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Note 1: If multiple simultaneous path failures, such as an optical fiber cut,
occur on different optical interfaces such as an OC-3, OC-12, OC-48 or
OC-192, the 60 ms switch time may not be met. Protection of simultaneous
path failures on multiple OC-n optical interfaces will complete in less than
200 ms.
occur on different optical interfaces such as an OC-3, OC-12, OC-48 or
OC-192, the 60 ms switch time may not be met. Protection of simultaneous
path failures on multiple OC-n optical interfaces will complete in less than
200 ms.
Note 2: VT1.5 management is not supported on OPTera Metro 3500
shelves equipped with STX-192 circuit packs.
shelves equipped with STX-192 circuit packs.
The Wait to Restore time and Signal Degrade Threshold are provisionable for
OC-48 and OC-192 optical interface pairs and DS1 circuit packs.
OC-48 and OC-192 optical interface pairs and DS1 circuit packs.
Note: DS1 user protection switch requests (including manual, forced and
lockouts) are automatically cleared after a network element power
failure/recovery.
lockouts) are automatically cleared after a network element power
failure/recovery.
On BLSR rings, user-initiated switches are supported as follows:
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Lockout on working channel on a span. This prevents a span from
switching. The node can still go into pass-through mode.
switching. The node can still go into pass-through mode.
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Lockout on protection channel on a span. This prevents the use of the span
for any protection switching. It also prevents ring switches anywhere in the
ring.
for any protection switching. It also prevents ring switches anywhere in the
ring.