Nortel Networks 3500, NTRN10AN manual Blsr Line Protection Oscillation Control

Operation, administration, and maintenance (OAM) features 2-13

BLSR Line Protection Oscillation Control

OPTera Metro Release 12.0 introduced a line protection oscillation control mechanism for BLSR systems. If 3 signal failures (SF) are detected on a line within 12 seconds of each other the line protection oscillation control mechanism is activated and protection will be in a lockout condition for 12 seconds. The OPTera Metro 3500 will raise an “Auto Switch Complete - Oscillation” alarm. The lockout condition is released only after 12 seconds have elapsed without a signal fail (SF) transition.

This feature is not provisionable and is always on.

BLSR single span fiber cut scenario

A fiber cut - and any other cause of signal degradation or signal failure on a span - causes a BLSR autonomous switch. A fiber degradation scenario is described in the following example. See Figure 2-4 on page 2-17to Figure 2-11 on page 2-24to see the following order of events after a signal degradation between Node 3 and Node 4 occurs.

Note: The following steps correspond to the step numbers in the graphics.

Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004