Cisco Certified Network Associate (CCNA) Practice Exam

What are the three bits used for controlling traffic congestion in a Frame Relay frame header?

1. Forward Explicit Congestion Notification, Backward Explicit Congestion Notification, Discard Eligibility

2. Forward Congestion Indicator, Backward Congestion Indicator, Frame Error Control

3. Forward Error Control, Backward Error Control, Discard Eligibility

4. Congestion Status, Frame Error Control, Discard Eligibility

The correct answer is: Forward Explicit Congestion Notification, Backward Explicit Congestion Notification, Discard Eligibility

The correct answer identifies the three specific bits used in the Frame Relay frame header that facilitate the management of network traffic congestion. Forward Explicit Congestion Notification (FECN) and Backward Explicit Congestion Notification (BECN) are two essential control mechanisms in Frame Relay technology. FECN is used to inform the destination that congestion has occurred in the network, while BECN signals the source that the congestion condition exists. These notifications are crucial for end systems to adjust their data transmission rates, thereby preventing potential data loss and maintaining network performance. The Discard Eligibility bit is another vital component in the Frame Relay header, indicating whether a frame can be discarded in the event of congestion. When the network experiences overload, frames with the Discard Eligibility flag set can be removed first, ensuring that higher-priority traffic is preserved. Together, these three bits work collaboratively to provide a robust means of traffic management in Frame Relay connections, allowing for dynamic adjustments based on current network conditions.