The application driver (COM.ibm.db2.jdbc.app.DB2Driver) requires local client software and a local database instance.
Because DB2 runs on a separate (often dedicated) host in most production environments, the local database instance usually contains an alias to the remote database instance. In this configuration, the local database instance uses a DB2-specific protocol to communicate with the remote database instance. This type of driver is the default on the DB2 Resource Parameters page.
The network driver (COM.ibm.db2.jdbc.net.DB2Driver) does not require local client software or a local database.
This driver does require that the DB2 Java Daemon (db2jd) be running on the target server. (In most production environments, the target server is a separate host, but the network driver works as well with a local database instance.)
This daemon is not started by default, but the database administrator can start it manually or configure it to start automatically when the database instance starts.