Initialization

A Call thread allocates a conversation to initiate the connection, at start-up time or outbound message write time if Delay is selected.

If EBCDIC Alloc is selected, then all strings that are copied into the allocation request are transliterated into EBCDIC. Otherwise, the driver uses ASCII.

The configuration value determines the conversation sync level. The driver always requests a MAPPED conversation.

If the security option is used, then the driver requests SECUR_PGM and includes the configured User ID and Password values; otherwise, it uses SECUR_NONE.

After the conversation is established, the driver sends a FLUSH. Because the CALL establishes the conversation, it has initial control of the conversation and is in the SEND state.

The Listen thread begins by opening the /dev/sna/profile_name pseudo-device where profile_name is the name of the configured SIP.

With that pseudo-device, it registers itself with SNA as the configured TPN.

If EBCDIC Alloc is selected, then the driver registers this string using EBCDIC instead of ASCII.

When the TPN is registered, the thread awaits conversation allocation requests. When one arrives, the driver retrieves the parameters in the request and checks the requested TPN and profile names. If all is well, then the driver allocates a conversation, enters the RECEIVE state, and waits for message data.