Because a network consists of devices sharing a common transmission capability,
some method to control usage of the medium is necessary to facilitate equal and fair
access to this common resource. First we will describe some medium access control techniques:
round robin, reservation, and contention. Then we will briefly examine three
common medium access control protocols used to implement access to resources: carrier
sense multiple access (CSMA); token passing; and distributed-queue, dual bus (DQDB).