Some development environments include several local area networks (LANs). For example, a company's intranet might include two LANs—a Sales LAN and a Manufacturing LAN.
The common OpenEdge administration architecture includes a method for connecting NameServers to other NameServers. When a NameServer receives a request for an application service, it checks to see whether any of the WebSpeed brokers registered with it supports that application service. If none of its registered brokers supports that application service, the NameServer passes the request to other NameServers that it knows about.
Using this capability, you can link OpenEdge installations across the LANs that make up a wide area network. The following figure shows the products installed on a multiple LAN configuration.
Figure 12. Multiple LAN development environment
In this configuration, the NameServer machine, Saturn, is the central communication point that routes requests to the WebSpeed Transaction Servers on both LANs. Requests start from workstations, like Prometheus (which has OpenEdge Studio installed on it). A workstation passes the request to the Web server machine, Pandora, which has the WebSpeed Messenger installed. The Messenger asks the NameServer on Saturn to find a WebSpeed Transaction Server that can handle the request, by specifying an application service with the WService parameter.
Calypso and Hyperion both have the Transaction Server installed. The Transaction Servers are registered with Saturn's NameServer. Saturn's NameServer checks its list of registered Transaction Servers to see whether one supports the application service that can handle the request from Pandora's Messenger. If one of them does, the NameServer passes its location back to the Messenger and the request is completed. The Transaction Server installed on Titan includes a NameServer. You can register this NameServer with Saturn's NameServer as a NameServer Neighbor. If the WebSpeed Brokers on Calypso or Hyperion do not support the correct application service, Saturn's NameServer passes the request to the NameServer on Titan to see whether the Broker registered with it supports that application service. If the Broker on Titan does support the application service, Titan's NameServer passes its location to Pandora's Messenger. Then the request is completed as normal.
For more information on how this works, see the section on using NameServer neighbors in OpenEdge Getting Started: Installation and Configuration.
Note that there are only two machines with data sources in this configuration—Hyperion, on the Windows side, and Atlas, on the UNIX side. Because the WebSpeed Transaction Server does not come with a database, you must install the Progress OpenEdge Enterprise RDBMS or the appropriate DataServer to connect to your non-OpenEdge database. The WebSpeed Agents on any of the Transaction Server machines in the configuration can access either data source.
