Once the connect service has been completed, the IrLAP communication processes can transfer information over the resulting connection. Data is the exchange of upper-layer protocol information. Status is a process that monitors the health of the IrDA link. In particular, the link quality is monitored for excessive noise and the presence of unacknowledged data transmissions. Reset is a process that, through mutual agreement of the two stations, causes all counters and timers to be reset.
Disconnection is the actual termination of a connection between two IrLAP stations.
When disconnecting, any unacknowledged data is discarded from local queues, with delivery not guaranteed. Given these services, we can now explore some of the mechanisms behind providing them. To understand the protocol exchanges used within IrLAP, it's a good idea to first understand the types of frames that are used in the protocol. If you've already invested some time in working with HDLC, there shouldn't be any significant surprises here. The supervisory frames contain sequencing information with no information and are used to control the flow of information within the constraints of a connection.