Maintenance and Administration Position 157• Protective controls restrict certain kinds of traffic to prevent systemdegradation (NET delays) resulting from overload.Note: Matching loss is defined as the average probability of a callnot being completed due to congestion in the NET or in the lineconcentration.Operational MeasurementsSystem performance is constantly and automatically recorded by theOperational Measurement (OM) system. The measurements are stored inOM registers, either individually every time an event occurs (a peg count) oron the basis of a scan that is conducted at regular intervals, regardless ofthe time of occurrence of the event (a usage measurement).Using a computer system, the recorded OM data can be manipulated invarious ways to generate statistics on aspects of Meridian SL-100 systemperformance, such as the following:• office maintenance• provisioning new equipment• analysis of traffic through trends on marginal conditions• balancing of traffic load through operable equipment• determining fluctuating service capacities• testing line and trunk performance and transmissionFor more information about Operational Measurements, see theCommunication Server 2100 Commercial Systems OperationalMeasurements Reference Manual (555-4031-814).Access control systemAccess to the Meridian SL-100 system data through the MAP is controlled,for security purposes, through logon procedures and access rightsaccording to user class.LogonEach authorized user is assigned a user name and password. No userinterface activity can be performed until the proper identification has beenentered and acknowledged by the MAP workstation. User names andpasswords can only be changed by the proper level of authorized user.Command and terminal accessAuthorized users are divided into user classes, depending on the functionsthat these users are required to perform. For example, one user may dotrunk maintenance and another may do network management. Each userCommunication Server 2100Meridian SL-100 Product Guide555-4001-103 20.01 StandardSE09 20 October 2006Copyright © 2006, Nortel Networks Nortel Networks Confidential.