Token Bus and Token Ring Protocols
To create a scenario and study the performance of Token Bus and Token Ring protocols through simulation.
Theory
Token-based protocols are collision-free medium access control (MAC) methods that regulate access to a shared channel using a control frame called a Token.
Token Ring (IEEE 802.5)
Nodes are physically connected in a ring. The token circulates in one direction. A node captures the token to transmit and releases it after the frame returns (source stripping).
Token Bus (IEEE 802.4)
Nodes are on a physical bus but form a logical ring. The token is passed based on descending node addresses. It combines the physical robustness of a bus with the deterministic nature of a ring.
These protocols provide deterministic access, meaning a node is guaranteed to get a turn to transmit within a predictable time frame, making them ideal for real-time applications.
Procedure
- Select the protocol mode: Token Bus or Token Ring from the lab interface.
- Set the Number of Nodes and Packet Size for the transmission.
- Observe the Token Circulation:
- In Token Ring, see it move physically around the circle.
- In Token Bus, see it jump between nodes in logical order.
- Trigger a transmission and follow the Data Frame as it travels across the network.
- Monitor the Throughput and Fairness metrics as multiple nodes compete for access.
- Complete the quiz to evaluate your understanding of predictable network delays.