The SNALink should build a message in a buffer and then call the Base to send it. The message contains source and destination LPIs, which are set up when the connection is opened; see LPI Connections for more information.
The SNALink can either obtain a new buffer to contain the message to be sent (using SNAGetBuffer) or reuse one in which it has previously received a message. The application is responsible for any buffer that it has obtained or in which it has received a message; it must either use (or reuse) the buffer to send a message or release it (using SNAReleaseBuffer). If a buffer to be reused does not contain the correct number of elements for the message to be sent, the application can obtain additional elements (using SNAGetElement) or release existing ones (using SNAReleaseElement). It is the application's responsibility to maintain the numelts field in the message header.
The function used to send a message to the node is SNASendMessage.