Nortel Networks NTRN10AN, 3500 manual Protection switching

2-118Operation, administration, and maintenance (OAM) features

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.

For more information about protection switching behaviour for specific circuit packs:

•OC-192 optical interface circuit pack on page 3-59

•OC-48 optical interface circuit pack on page 3-65

•OC-48 STS optical interface circuit pack on page 3-68

•OC-12 optical interface circuit pack on page 3-72

•OC12x4 STS IR optical interface circuit pack on page 3-75

•OC-3 optical interface circuit pack on page 3-77

•OC-3x4 optical interface circuit pack on page 3-80

•EC-1x3 circuit pack on page 3-82

•EC-1x12 circuit pack on page 3-84

•DS1 mapper on page 3-86

•DS3x3 mapper on page 3-87

•DS3x12 / DS3x12e mapper on page 3-89

•DS3VTx12 mapper on page 3-90

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.

Note 2: VT1.5 management is not supported on OPTera Metro 3500 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.

Note: DS1 user protection switch requests (including manual, forced and lockouts) are automatically cleared after a network element power failure/recovery.

On BLSR rings, user-initiated switches are supported as follows:

•Lockout on working channel on a span. This prevents a span from switching. The node can still go into pass-through mode.

•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.

OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004