Cisco Certified Network Associate (CCNA) Practice Exam 2025 - Free CCNA Practice Questions and Study Guide

The characteristic of Frame Relay point-to-point subinterfaces that makes option B correct is that they emulate leased lines and require a unique subnet. In a Frame Relay environment, point-to-point subinterfaces are configured to create a dedicated link between two endpoints, making them behave similarly to traditional leased lines. Each point-to-point subinterface is assigned its own IP subnet, which helps manage addressing and routing more effectively within a Frame Relay network.

When using point-to-point subinterfaces, it is crucial to understand that each subinterface must have its own subnet. This allows for clear identification and separation of traffic flowing over different subinterfaces, enhancing network organization and performance.

The other options do not align with key features of Frame Relay point-to-point subinterfaces. For instance, while some aspects of configuration are straightforward, saying they require no additional configurations overlooks the necessity of subnetting and addressing. Additionally, while the point-to-point nature of these subinterfaces indicates a single connection between two devices, it does not restrict their use to merely "only" single connections. Finally, Frame Relay itself does not typically support variable-length Data Link Connection Identifiers (DLCIs) within this context, as DLCIs are generally fixed-length, thus highlighting the fundamental differences between various configurations in a