Reservation:

Medium access control techniques is suitable for the stream traffic. The total time on medium is divided into slots similar to synchronous TDM. A station that wants to transmit reserves the future slots for extended or even indefinite period. The reservation may be made in a centralized or distributed manner.

Scheduling for medium access:

1. Schedule frame transmissions to avoid collision in shared medium.
2. More efficient channel utilization.
3. Less variability in delays.
4. Can provide fairness to stations.
5. Increased computational or procedural complexity. .

6. Two main approaches:

   (i) Reservation (ii) Polling

Collision- free reservation systems:

• Transmission organized into cycles.
• Cycle: Reservation interval + frame transmissions
• Reservation interval has a mini-slot for each station to request reservation for frame transmission.

Reservation system options:

1. Centralized or distributed system

   • Centralized systems: A central controller listens to reservation information, decides order of transmission issues grants.
   • Distributed systems: Each station determines its slots for transmission can be reserved within the reservation cycle.

2. Single or multiple frames:

   • Single frame reservation: Only one frame transmission can be reserved within a reservation cycle.
   • Multiple frame reservation: More than one frame transmission can be reserved within a frame.