Locate resource: EN to NN to two ENs

Figure 1. Locate resource: EN to NN to two ENs

Note: Nodes are connected by CP-CP sessions only.

The end node sends a search request for a target resource to the network node server. The network node server looks for the target resource in the directory database. The end node that owns the resource did not register its resources.
The APPN control point (CP) requests that the subarea SSCP check for information about the location of the resource.
The subarea SSCP replies that the target resource is not known.
Because NN does not have the target resource in either its APPN or subarea directories, it initiates a resource discovery search. The research discovery search starts at the beginning of the search logic with a generic request, which is not linked to the original OLU. Because the resource discovery search starts at the beginning of the search logic, another CACHE_SEARCH is performed.
The subarea SSCP replies that the target resource is not known.
The network node server performs a domain broadcast by sending the search request to all served end nodes that indicate on the CP_CAPABILITIES exchange that they are to be searched on domain broadcast.
Each end node that receives the request replies to the search request. EN1 replies that the resource is not found. EN2 replies that it owns the resource.
Because the resource discovery search found the resource, the NN sends a search to the target, containing the original session-specific information.
The target is found.
The network node server replies to the end node.