In the UMTS, resource reservation is provided by using unidirectional RSVP messages
to set up a bi-directional PDP context. The MT 30 and a support node 24
can be arranged to compare incoming RSVP messages with any existing secondary
PDP context, and if a match is found, no action is taken on the incoming message.
The match is made by determining whether a flag is set. This eliminates "racing"
when each end of an RSVP session sends an RSVP message.
