Control messages are used for handshakes and other communication, located in the NI layer. These messages are based on the same structure as the NI Error Information. None zero operation code indicates a message. The following control messages are known in NI version 36:
NI control messages
NI version request
NI version response
NI send handle (4 messages)
SNC control messages:
SNC request from client side
SNC request from server side
SNC handshake completed