Configuring NameServer communications
Both clients and Unified Brokers use User Datagram Protocol (UDP) to communicate with NameServers. UDP is an Internet standard, combined network layer, transport layer, and session layer protocol that provides a mechanism for connectionless communications. The connectionless nature of this protocol affords built-in benefits, such as the ability to implement fault-tolerant NameServers for client connections. For information on connection-level fault tolerance, see Appendix E "NameServer Load Balancing Details."
To establish a Unified Broker connection, a Unified Broker client must specify the location of the NameServer that provides the connection. To register with a NameServer, a Unified Broker must specify the location of the NameServer where it needs to register. To specify the NameServer location, both components must know the UDP port number (or service name) on which the NameServer is listening and the host address of the machine where it resides.
Specifying NameServer ports and hosts
4GL clients provide this information when they specify the CONNECT( ) method, and AppServer Open Clients provide it using an equivalent Open Client method. You must specify this information for NameServers and other Unified Broker components in the Progress Explorer or directly in the Unified Broker properties file (ubroker.properties). For more information, see the "Configuring OpenEdge Unified Broker components" section.
If the component uses a UDP service name rather than a port number, you must also ensure that the services file on the component host (or Network Information Services (NIS), if used) properly defines the UDP service name.
Editing the services file
The services file stores the service name, port number, and protocol for various services on the network. For each NameServer that the component accesses, the services file on the component host must specify a service name associated with the NameServer UDP port number (default, 5162). Thus, if the component connects using the service name namesv, you might enter the service name definition for the services file extract shown in Figure 11–4.
