Clerks

In order to build server lists and synchronize with the servers on the list, clerks need to be able to locate servers automatically. They discover servers by using Remote Procedure Call (RPC) profiles. Recall that profiles are search tables that contain the following types of entries:

· Server Entries - The CDS names of individual resource providers.

· Service Group Entries - A group of resource providers identified by a single CDS name.

· Profile Entries - The names of other configuration profiles. These entries allow hierarchical nesting of profiles.

Each DTS clerk node contains up to three profiles. When it attempts to locate servers, a clerk first performs an RPC lookup of the entries in a base profile called the node initial profile. The clerk then looks for the LAN profile entry. If the LAN profile entry is not found, the clerk searches for the default profile entry; the default profile may contain the LAN profile entry. When the clerk locates the LAN profile, it reads the server entries to build a list of local servers. This process is repeated at set intervals.

If a clerk does not obtain enough server entries as dictated by the DTS management attribute minservers, it attempts to locate additional servers, usually those outside the LAN. To locate these servers, a clerk locates the cell profile, which has a well-known CDS name. The cell profile contains global server entries; that is, servers that are normally found outside the LAN. (See Servers for further information.)

After building a server list with enough entries, a clerk can directly request time values from several of the servers on the list. The clerk then receives these time values and uses them to compute a new system time for its client system.