Release 10.1A: OpenEdge Getting Started:
Installation and Configuration

> ## NameServers

> A NameServer is a single process that mediates client connections for a set of Unified Brokers that have registered with it. Any number and type of Unified Broker instance can register with a single NameServer, and each Unified Broker instance can register with exactly one NameServer. The NameServer that a broker instance registers with is the broker’s controlling NameServer.

> Note: Keep in mind that the NameServer is not required. The use of this element will depend on your implementation.

> When a Unified Broker instance starts up, it can register with its controlling NameServer by sending its location and other configuration information. The NameServer uses this information to help resolve client connection requests. Part of this registration information is the Application Service that the Unified Broker supports. An Application Service is a designation for the particular business function that a Unified Broker provides. For more information on Application Services, see the "Working with Unified Brokers" section.

> NameServers provide the following services for a Unified Broker product:

> - Location Transparency — A requesting client does not need to know the network location of a Unified Broker instance. When a client attempts to create a connection to a Unified Broker instance, it first requests the connection from a NameServer to a broker that provides a specified Application Service. The NameServer then locates and assigns a broker to complete the connection that provides the specified Application Service.

> - Server-level fault tolerance and load balancing — If you have installed the load-balancing option, you can provide server-level fault tolerance, where the NameServer can select from several Unified Broker instances to satisfy a client request. This option also allows you to balance connection load among multiple Unified Broker instances that provide the same Application Service. The NameServer then assigns connections among several Unified Broker instances based on a weight factor that you configure for each instance. For more information on server-level fault tolerance and how load balancing affects Unified Broker operations, see Appendix E "NameServer Load Balancing Details.". And, note that any NSMAN command that specifies a username typically also prompts for a password. For complete information about the syntax and options of the NSMAN command-line utility, see the "NSMAN" section.

> - Connection-level fault tolerance — You can also make multiple NameServer instances available to help ensure that at least one NameServer is available even if another fails. In this type of configuration, one of several possible NameServers resolves the connection request. Thus, you can provide connection-level fault tolerance for requesting clients. For more information on connection-level fault tolerance, see Appendix E "NameServer Load Balancing Details."

> For more information on how your Unified Broker product uses NameServers, see your product documentation.

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