Client-to-server communications configuration overview

Understanding client-to-server communications: Components and scenarios

The basic components involved in client-to-server communications are described below:

• Client. This refers to the initiator of the communications. This role can be filled by any of the following DB2® products or components:
  • IBM Data Server Driver Package
  • IBM Data Server Client or IBM Data Server Runtime Client.
  • DB2 Connect™ Personal Edition: This product is a superset of the IBM Data Server Client.
  • a DB2 server product: A DB2 server is a superset of the Data Server Client.
• Server. This refers to the receiver of the communications request from the client. This role is normally filled by a DB2 for Linux, UNIX, and Windows server product. When DB2 Connect products are present, the term server can also mean a DB2 server on a midrange or mainframe platform.
• Communications protocol. This refers to the protocol used to send data between the client and server. The DB2 product supports several protocols:
  • TCP/IP. A further distinction can be made between the version: TCP/IPv4 or TCP/IPv6.
  • Named Pipes. This option is available on Windows only.
  • IPC (interprocess communications). This protocol is used for local connections.

When setting up a server to work with development environments (such as IBM Data Studio), you might encounter error message SQL30081N at the initial DB2 connection. A possible root cause is that the firewall at the remote database server has prevented the connection from being established. In this case, verify the firewall is properly configured to accept connection requests from the client.

Understanding client-to-server communications: Types of connections

Generally speaking, references to setting up client-to-server communications refer to remote connections, rather than local connections.

A local connection is a connection between a database manager instance and a database managed by that instance. In other words, the CONNECT statement is issued from the database manager instance to itself. Local connections are distinctive because no communications setup is required and IPC (interprocess communications) is used.

A remote connection is one where the client issuing the CONNECT statement to a database is in a different location from the database server. Commonly, the client and server are on different machines. However, remote connections are possible within the same machine if the client and server are in different instances.

Another less common type of connection is a loopback connection. This is a type of remote connection where the connection is configured from a DB2 instance (the client) to the same DB2 instance (the server).

Comparison of methods for configuring client-to-server communications

Several methods are available for configuring client-to-server communications. Choosing a suitable method involves answering two questions. The first is Which tool will you use: Configuration Assistant or command line tools?

• The Configuration Assistant is a graphical tool provided with versions of the Data Server Client and DB2 server products on Windows and Linux on Intel™ x86 32-bit platforms and AMD64/EM46T platforms. This tool is not provided with the Data Server Runtime Client.
• The command line tools consist of the Command Line Processor (CLP), and the commands db2cfexp (configuration export), and db2cfimp (configuration import).

The second question is: What type of configuration task do you want to perform? Options are:

• Configure a client by entering information manually.
• Configure a client by searching the network for servers to connect to.
• Make databases on a server accessible to one or more clients.
• Use the connection settings for one client as the basis for configuring additional clients.

With answers to these questions, you can use the table below to identify the appropriate configuration method. Links to each method are provided at the end of this topic. Notes follow the table that provide more details.