Cisco Certified Network Associate (CCNA) Practice Exam

What is the function of the Data Link Connection Identifier (DLCI) in Frame Relay?

1. To assign a globally significant address

2. To specify the virtual circuit for outgoing frames

3. To regulate network data flow

4. To identify the Frame Relay switch

The correct answer is: To specify the virtual circuit for outgoing frames

The Data Link Connection Identifier (DLCI) plays a crucial role in Frame Relay networks by uniquely identifying the virtual circuit over which frames are transmitted. Specifically, the DLCI is used to specify the virtual circuit for outgoing frames, allowing the Frame Relay network to route data to the appropriate destination. Each DLCI is associated with a particular path or logical connection between two endpoints in the network, ensuring that data is effectively managed and directed without ambiguity. The significance of the DLCI becomes apparent when considering how Frame Relay operates. Network devices, such as routers, rely on the DLCI contained in the frame headers to determine the correct path for the data packets they send. This enables multiple connections to share the same physical link while maintaining separate logical connections, enhancing the efficiency of network resource utilization. Additionally, while other options pertain to different aspects of network operation, they do not accurately reflect the specific purpose of the DLCI within the context of Frame Relay. For instance, the assignment of globally significant addresses and regulation of network data flow involve other protocols and mechanisms rather than the direct role of DLCI in identifying virtual circuits. Understanding the function of DLCI is essential for effective network design and troubleshooting in Frame Relay environments.