Selecting communications protocols

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

By default, the personal database server starts only the shared memory protocol.

The personal database server (dbeng12.exe) supports the following protocols:

Shared memory This protocol is for same-computer communications, and always remains available. It is available on all platforms.
For same-computer communications, shared memory tends to provide better performance than TCP/IP.
TCP/IP This protocol is for same-computer communications from TDS clients, Sybase Open Client, or the jConnect JDBC driver. You must use TCP/IP if you want to connect from Sybase Open Client or jConnect. It is available on all platforms.
For more information about TDS clients, see Using SQL Anywhere as an Open Server.

Available protocols for the network server

By default, the network database server starts all available protocols. You can limit the protocols available to a database server using the -x option. See -x dbeng12/dbsrv12 server option.

The network database server (dbsrv12.exe) supports the following protocols:

Shared memory This protocol is for same-computer communications, and always remains available. It is available on all platforms.
TCP/IP This protocol is used for communications between different computers, and you must use TCP/IP if you are using TDS clients, Sybase Open Client, or the jConnect JDBC driver. It is available on all platforms.

Shared memory and terminal services

When using terminal services, shared memory clients can only find database servers running in the same terminal. If you use terminal services with a database server that is running as a service, only clients running on the console can connect. Clients running on non-console terminals cannot connect over shared memory. In these situations, you can use TCP/IP instead of shared memory to allow clients to connect.

For information about securing shared memory connections on Unix, see Security tips.