The default configured switch has an empty MAC address table at this time , and Host A connected to the switch issues the first unicast data frame, so what will the switch do after receiving the teaching system?( Single choice questions).

When a switch with an empty MAC address table receives a frame, it first performs source MAC address learning. It examines the frame's source MAC address and the port on which it arrived, creating an entry in its MAC address table to map that MAC address to that port. Since the destination MAC address is not in the table (it's an "unknown unicast"), the switch cannot forward the frame to a specific port. Instead, it floods the frame out of all other ports within the same VLAN, ensuring the frame reaches its intended destination if it exists on the network.

A. The switch only drops frames for reasons like a failed Frame Check Sequence (FCS) or a security policy violation, not for an unknown destination MAC.
C. The switch cannot forward to a specific interface because the destination MAC address is not yet in its MAC address table.
D. Switches are designed for wire-speed forwarding; they do not cache frames and wait for a response. They act immediately based on the current MAC table state.

1. Huawei Enterprise Support, "HedEx V200R019C10, Configuration Guide - Ethernet Switching", Section: "MAC Address Table Configuration", Subsection: "Principles". It states: "If the destination MAC address of a received data frame is not found in the MAC address table, the switch floods the data frame in the corresponding VLAN."

2. Huawei Enterprise Support, "HCIA-Datacom V1.0 Training Material", Chapter: "Ethernet Switching Principles". This material explains the three primary functions of a switch: MAC address learning, frame forwarding/filtering, and loop prevention. The scenario described directly relates to the learning and forwarding (flooding for unknown unicast) functions.