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Application and Integration Services
OpenEdge Application Server Architecture : Understanding the AppServer : AppServer architecture

AppServer architecture

The following figure shows the architecture of the AppServer. The dotted arrows and borders show optional interactions and components.
Figure 5. AppServer architecture
An AppServer application can include the following components, potentially distributed on the following machines, as shown in the above figure:
1. AppServer client — This can be:
*Any OpenEdge application, including a GUI or Character client, a WebClient, a WebSpeed agent, or another AppServer agent
*An Open Client (.NET or Java)
*An industry Web service client
For more information, see AppServer clients overview.
2. AppServer adapter — (Optional) This can be the:
*AppServer Internet Adapter
*Web Services Adapter or OpenEdge Adapter for Sonic ESB
For more information, see AppServer adapters overview.
3. NameServer — A process that accepts a client request for connection to an AppServer and directs that request to the appropriate AppServer instance. This is optional depending on the AppServer configuration. If your application service is supported by multiple AppServer instances, you must use the NameServer for effective connection management.
4. AppServer — A core product set that contains the following components:
*AppServer agent — A process that executes ABL procedures in response to remote procedure requests and returns the results as ABL output parameters, return values, and errors. An AppServer agent is essentially an OpenEdge session with its user interface replaced by a network interface.
*AppServer broker — The process that manages client connections and its pool of AppServer agents, or agent pool, to execute client requests.
An AppServer instance:
*Is one AppServer broker and the pool of AppServer agents that it manages
*Has a specified configuration and makes a well-defined set of ABL procedures available as an application service for execution by client applications
*Can have any number of AppServer agents to service remote procedure requests from any number of client applications, depending on licensing and available resources
An AppServer installation is the AppServer part of an OpenEdge Application Server environment installed on a particular machine. Depending on your licensing and resources, you can configure and run multiple AppServer instances for a given AppServer installation.
The AdminServer is the core of the Unified Broker framework used to manage the AppServer and most of its related components. For more information on the framework, see Unified Broker framework.