DB2 Version 9.7 for Linux, UNIX, and Windows

Client/server connection options

DB2 Connect™ server provides a single point of connectivity to numerous workstations supporting a variety of applications. However, it requires extra resources for applications accessing DB2® for z/OS® data and increases the elapsed time of those applications.

Starting with DB2 Connect Version 8, DB2 Connect clients use the DRDA® protocol natively to connect directly to DB2 for z/OS and DB2 for IBM® i. Using DB2 Connect clients is a less resource intensive way to obtain the connection and application development functionality of the DB2 Connect server.

Advantages of using a DB2 Connect server

The DB2 Connect server is advantageous in the following situations:

For two-phase commits, if you are using transaction managers that use a dual transport model
For Homogeneous Federation

Advantages of using a DB2 Connect client

You can replace a DB2 Connect server with a DB2 Connect client, choosing from among the various IBM data server drivers, the IBM Data Server Runtime Client, or the IBM Data Server Client. The DB2 Connect client and drivers offer functionality that is equivalent or superior to that of DB2 Connect server and include the following other advantages:

Enhanced performance. You can achieve better performance due to less network traffic and code paths. DB2 Connect clients simplify network topology, since a direct connection is established between the application server and DB2 z/OS. This will also eliminate network hop and DB2 Connect gateway routing. Reduced resource consumption means hardware or software resources are not required for DB2 Connect server machines.
Reduced footprint. By replacing DB2 Connect server with DB2 Connect client, you can reduce complexity and deploy application solutions with smaller footprints and achieve overall benefits.
Improved availability. Accessing DB2 for z/OS applications using IBM data server drivers or clients eliminates a point of failure and provides equal or superior performance due to a three-tier configuration.
Improved monitoring. A direct connection makes it easier to monitor application server or web application server traffic and behavior.
Improved problem determination. If ant application experiences a performance problem, the presence of the DB2 Connect server complicates the efforts to identify the source of the problem.
Latest code levels. You can obtain the latest code levels to exploit new server features and APIs. Data support for some features such as new data types is easier to obtain.

If you replace a DB2 Connect server with a DB2 Connect client, DB2 Connect license files are required. In a DB2 Connect server configuration, DB2 Connect entitlement is stored at the DB2 Connect server, not at individual clients. If you change to direct client connectivity, you must store the DB2 Connect entitlement at each client.