This management information module supports the configuration and management of SONET linear APS groups. The definitions and descriptions used in this mib have been derived from GR-253-CORE Revision 2, January 1999, section 5.3. The mib contains four tables. The apsConfigTable supports addition, modification and deletion of entries representing linear APS groups. Ring APS groups are not currently supported by this MIB. Entries are indexed by a text group name. Each entry contains parameters that specify the configuration of a particular linear APS group. The apsCommandTable provides linear APS commands that support protection switching and the ability to modify APS operation. Commands may only be entered if the corresponding apsConfigRowStatus instance is set to active. The apsStatusTable provides statistics and information about the current APS group state. The apsChanTable provides the ability to add and delete SONET LTE channels from APS groups. Additionally statistics and current state information are provided at the APS channel level. The table contains entries for each SONET LTE interface available on the system. The field apsChanGroupName is initially set to a string of size zero indicating that the SONET LTE is not part of an APS group. Fields that are associated with APS configuration may be modified. An apsChanEntry instance may not be added or deleted through rbnApsMIB mib access operations. However, an apsChanEntry may be added or deleted through other system mechanisms, such as hot swap. An APS group is created and configured with the following sequence of events: CHANNEL CONFIGURATION Set the apsChanGroupName in an apsChanEntry to a user-friendly text string. The string must not be equal to the apsConfigName of an existing apsConfigEntry with apsConfigRowStatus set to active, since a channel cannot be added to an active group. The string may be set equal to the apsConfigName of a row which is currently not set to active, or it may be set to a string which does not currently exist in any instance of apsConfigName. A channel number is entered in apsChanNumber. A channel priority is entered in apsChanPriority, if the intended architecture is 1:n. apsChanPriority is ignored if the architecture is 1+1. This step is repeated for all apsChanEntry instances which are to be included in the APS group. ACTIVATING THE GROUP If the apsChanGroupName does not exist in an instance of apsConfigName, an apsGroupEntry is created with the apsChanGroupName value used as the index for the row. The apsConfigRowStatus value may be set to createAndGo. The apsGroupConfigEntry and apsChanEntry instances with matching name fields will be checked for consistency. If any errors in the channel numbers, architecture or configuration are uncovered the apsConfigRowStatus set will return inconsistentValue , otherwise noError is returned. If the apsChanGroupName value used in channel configuration exists in a previously created, inactive apsChanEntry instance, the apsConfigRowStatus value may be set to active.