Arbitration by scheduling: Token rings
Each station is connected to the ring via a repeater with two links
Links are connected serially to form a ring
Token protocol -- round-robin scheduling
- A single token frame circulates along the ring
- Node receives the token and is granted access
- Token-holding node sends addressed message(s)
- Addressee accepts message and repeats it
- The sender sees own message, “removes” it and regenerates the token
Both logical and physical rings are possible