SPX stanza of the qm.ini file (Windows only)

Use the SPX stanza in the qm.ini file, to specify SPX protocol configuration parameters.

Alternatively, on Linux® (x86 and x86-64) and Windows, use the IBM® MQ Explorer SPX queue manager properties page.

Socket= 5E86 (default) | socket_number

The SPX socket number in hexadecimal notation. The default is X'5E86'.

BoardNum= 0 (default) | adapter_number

The LAN adapter number. The default is adapter 0.

KeepAlive=NO|YES

Switch the KeepAlive function on or off.

KeepAlive=YES causes SPX to check periodically that the other end of the connection is still available. If it is not, the channel is closed.

Library1= DLLName1

The name of the SPX DLL.

The default is WSOCK32.DLL.

Library2= DLLName2

The same as LibraryName1, used if the code is stored in two separate libraries.

The default is WSOCK32.DLL.

ListenerBacklog=number

Override the default number of outstanding requests for the SPX listener.

When receiving on SPX, a maximum number of outstanding connection requests is set. This can be considered to be a backlog of requests waiting on the SPX socket for the listener to accept the request. The default listener backlog values are shown in Table 1.

Table 1. Default outstanding connection requests (SPX)

Platform	Default ListenerBacklog value
Windows Server	100
Windows Workstation	5

Note: Some operating systems support a larger value than the default shown. Use this to avoid reaching the connection limit.

Conversely, some operating systems might limit the size of the SPX backlog, so the effective SPX backlog could be smaller than requested here.

If the backlog reaches the values shown in Table 1, the SPX connection is rejected and the channel cannot start. For message channels, this results in the channel going into a RETRY state and retrying the connection at a later time. For client connections, the client receives an MQRC_Q_MGR_NOT_AVAILABLE reason code from MQCONN and should retry the connection at a later time.