When the central directory server receives a search request, it checks its database for the resource. If it does not find the resource in its database and there are other central directory servers in the network, it sends the search to the other central directory servers only. The selection of alternate central directory servers can be customized by using the alternate CDS selection function of the directory services management exit. If the central directory server receives a positive reply from any of the other central directory servers, it verifies the information, updates its own database with the information, and notifies the originating network node of the location of the requested LU. If the central directory server receives negative replies from all the other central directory servers, it initiates a broadcast search. If the central directory server that received a search request locates the resource in its own database, it verifies the information with a directed search and sends a reply to the originating network node server with the location of the requested LU.

If the central directory server does not find the resource in its database and there are no other central directory servers in the network, it initiates a broadcast search.