What is the VTAM search reduction function, and how can it be enabled?

When a resource is unreachable in a network, futile attempts to reach it can still occur. Excessive searching for unreachable resources can adversely affect network performance. Therefore, VTAM provides search reduction support, which limits requests for unreachable resources.

If search reduction support is enabled, an APPN or subarea search reduction entry is created when a resource discovery search (RDS) fails to locate a target resource. VTAM then reduces searching for the unreachable resource in the appropriate part of the network during a designated amount of time or until a designated number of requests have been received for the resource.

To use VTAM search reduction support, code the SRCHRED=ON start option or enter the MODIFY VTAMOPTS command with the SRCHRED=ON operand.

Use the SRTIMER start option, or MODIFY VTAMOPTS with the SRTIMER operand, to designate the amount of time that VTAM should limit requests for a resource. Use the SRCOUNT start option, or MODIFY VTAMOPTS with the SRCOUNT operand, to designate the number of requests for a resource that VTAM should limit before attempting to locate the resource again.

Use the D net,VTAMOPTS command to display the current settings of the search reduction start options.