The OpenLink? Multi-Tier ODBC Driver for Progress comprises two parts.
On the server you install a request broker which handles incoming connections, and a database agent which makes the connection to the database itself.
On data-consuming machines (clients or application-servers), you install a generic client. This approach presents an extra layer of abstraction, such that by installing one component on each client, you can connect to several servers, or several different databases via the same broker.
Multi-tier is ideally suited to larger installations where the network administrator wishes to handle security rules and performance configurations centrally.
The OpenLink? Multi-Tier Drivers for Progress are a Type A class driver developed using the ESQL/C and SQL-92 call level interface.
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/Progress Multi-Tier Architecture Diagram Image scaled down; Click to enlarge./