Nortel Networks NTRN10AN, 3500 manual Alarm flow control

2-6Operation, administration, and maintenance (OAM) features

audible and visible office alarm outputs). The network element, whether the alarm point is disabled or enabled, records all alarms when the conditions that cause an alarm occur.

Alarms are not lost after they are activated, whether enabled or disabled, and can be retrieved when they are enabled. OPTera Metro 3500 stores a maximum of 3000 active alarms, including both enabled and disabled alarms. The Active Alarms window of Site Manager does not identify active disabled alarms. You can retrieve a list of all disabled alarms from the Alarm Provisioning window, by clicking the Alarms on Disabled Points tab.

Alarm profiles allow you to enable or disable defined groups of alarm points. These groups are defined as Alarm classes. Alarm points are grouped by facility type or equipment.

Each group of alarm points has two profiles defined by the system: All Alarms ON and All Alarms OFF. At start-up, every group of alarm points has a default profile of All Alarms ON, which becomes the active profile. You can create up to three profiles for any group of alarm points. Each profile has a distinct name and contains status information for each alarm or event that applies to that profile. Profile names can contain an ASCII string of up to 20 characters that cannot include quotation marks (“) or backslashes (\).

You can create, edit, and delete profiles. You can change all profiles, except the two profiles defined by the system. However, you cannot delete or edit a profile that is set as the default profile, or edit or delete the active profile if it is in use. A new profile can be added to take care of additional requirements.

Alarm flow control

When a major fault occurs within a network, significant numbers of alarms are raised on each shelf processor over a sustained period of time. The alarm flow control (AFC) feature avoids situations in which Site Manager sessions log out automatically due to TL1 request timeouts.

If the alarm rate is four alarms / second or greater, in a given ten minute period, then this condition is considered excessive alarming and the ‘Alarm and Event Throttling Active’ alarm is generated to warn users that further alarms will not be reported.

When the system initiates alarm flow control, applications can continue to generate alarms. The AFC feature only disables the reporting of alarms to the screen or to file. User-initiated retrievals will continue to display all the alarms.

When the number of alarms being generated falls below the provisioned threshold, the ‘Alarm and Event Throttling Active’ alarm is cleared and alarm reporting resumes.

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