CN

Token Bus and Token Ring Protocols

Medium
EST. TIME: 45 min

Token Bus and Token Ring Protocols

To study Token Bus and Token Ring protocols.

Theory & Concepts

Click to collapse detailed explanation

1. Introduction

Unlike CSMA/CD which is random (probabilistic), Token Passing protocols are **deterministic**. They use a special control frame called a **Token** that circulates around the network. Only the station holding the token can transmit.

2. Protocol Comparison

Token Ring (IEEE 802.5)

  • Topology: Physical Ring.
  • Mechanism: Token passes from neighbor to neighbor.
  • Priority: Supports priority bits for QoS.

Token Bus (IEEE 802.4)

  • Topology: Physical Bus, Logical Ring.
  • Mechanism: Token passes to the station with the next lower numeric address.
  • Use Case: Industrial automation (MAP).

3. Advantages

  • Collision Free: Since only one token exists, collisions are impossible.
  • Fairness: Every station gets a guaranteed chance to transmit.
  • Real-time capable: Maximum wait time is predictable.

Procedure

1

Select Topology

Choose Token Ring or Token Bus mode.

2

Track Token

Observe the token (highlighted packet) moving sequentially.

3

Transmit

Queue a message at Node A. Notice it waits until it receives the token to start sending.

Learning Resources

Animated Lecture

Token Ring vs Token Bus

Reference Notes

Token Passing Mechanism

Self Quiz

Token Protocols Quiz

Ready to Start?

Launch the virtual simulator to visualize the network layers and verify protocols.

Lab Status

Active Simulation

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