Communication protocol considerations

Any communication between a client application and a database server requires a communications protocol. SQL Anywhere supports communications protocols for communications across networks and for same-computer communications.

Available protocols for the personal database server (dbeng12)

By default, the personal database server allows only shared memory connections. To also start the TCP/IP protocol, use the -x option. See -x dbeng12/dbsrv12 server option.

Shared memory This protocol is for same-computer communications and it is always available on all platforms.
For same-computer communications, shared memory tends to provide better performance than TCP/IP.

For information about securing shared memory connections on Unix, see Set SATMP environment variable to a unique directory (Unix).
TCP/IP This protocol is available only for same-computer communications on the personal server. In addition, you must use TCP/IP if you are using TDS clients (Sybase Open Client or jConnect JDBC driver). It is available on all platforms.
For more information about TDS clients, see SQL Anywhere as an Open Server.

Available protocols for the network database server (dbsrv12)

By default, the network database server starts the shared memory and TCP/IP protocols. You can provide TCP/IP protocol options or disable the TCP/IP protocol using the -x option. See -x dbeng12/dbsrv12 server option.

Shared memory This protocol is for same-computer communications and it is always available on all platforms. For information about securing shared memory connections on Unix, see Set SATMP environment variable to a unique directory (Unix).
TCP/IP This protocol is used primarily for communications between different computers. You must use TCP/IP if you are using TDS clients (Sybase Open Client or jConnect JDBC driver). It is available on all platforms. For more information about TDS clients, see SQL Anywhere as an Open Server.

Connecting from a SQL Anywhere client

Shared memory Shared memory is the default connection protocol. To connect over shared memory, do not include either the Host or CommLinks connection parameters in the client's connection string.
TCP/IP To connect over TCP/IP, specify either the Host or the CommLinks connection parameter. The Host connection parameter is recommended. See Host connection parameter and CommLinks (LINKS) connection parameter.