200-301 Practice Questions

A frame that fails the Ethernet Frame Check Sequence is counted as a CRC error and also contributes to input errors. The FCS field is the Ethernet trailer’s error-detection value; the receiver recalculates the value and compares it with the frame’s received FCS. If the values do not match, the frame is considered corrupted and is discarded. Cisco interface counters commonly report that condition under CRC, while the broader input errors counter includes CRC and other receive-side problems such as runts, giants, frame errors, overrun, ignored, and no-buffer conditions. Runts and giants are size-related counters, not the direct result of the FCS failure described in the question. The frame counter is not the best paired answer here. In CCNA 200-301 v1.1 Network Fundamentals, this maps to Ethernet operation and interface troubleshooting. The verified answers are D and E: CRC and input errors. Reference: Cisco interface counter interpretation and Ethernet FCS behavior.

A Layer 2 switch forwards frames within a VLAN and makes forwarding decisions based on MAC addresses. It learns source MAC addresses from ingress frames, records the associated port in the MAC address table, and forwards known destination frames out the matching port. If the destination is unknown, it floods within the VLAN. A Layer 2 switch does not select the best WAN route between networks; that is a router or Layer 3 switch function. It also does not normally move packets between different VLANs unless Layer 3 routing is involved. The existing answer that included a central point for association and authentication servers is not a Layer 2 switch function; that wording better resembles wireless or authentication infrastructure. Cisco CCNA 200-301 v1.1 Network Access expects a clean separation of switching and routing duties. The two valid Layer 2 switch functions are moving frames within a VLAN and forwarding based on MAC address.

The two options that improve WAN scalability and reliability are dual-homed branches and dynamic routing. A dual-homed branch has more than one upstream connection, which reduces the chance that a single circuit, provider, or edge device failure disconnects the site. Dynamic routing improves scalability because routes can be learned, withdrawn, and recalculated automatically as the WAN changes. Static routing can work in small topologies, but it becomes operationally fragile at scale. Single-homed branches are simpler but less resilient. The listed ' asynchronous routing ' choice is not the correct CCNA design answer for business scalability and reliability. Cisco CCNA 200-301 v1.1 IP Connectivity expects engineers to understand that redundancy and automatic route convergence are core design tools. A WAN with dual connectivity and dynamic routing can survive failures and grow with less manual intervention. Therefore, the corrected answer is C and

E.