When hosts agree to make a reservation for a certain session, the control architecture has to set up the connection; the RSVP process knows the switch status, the addresses of the hosts willing to communicate, therefore it knows the ports to which they are connected, and the service that they request.
The TrafficControl's original role is to supply requested QoS to data streams. Its role has been enhanced: when a new reservation is made, an ATM connection is established using the Ariel interface; when a reservation is deleted, the connection is torn down using the same mechanism.
ArielPortInfo objects are used to store the switch state: for each port, there is a list of QoS vectors (see [#!Ariel!#]) describing the context of each connection established.