Final Answer:
In a PVST (Per VLAN Spanning Tree) network, the switch learns MAC addresses and processes BPDUs in the forwarding and learning port states.Therefore the correct option is C. forwarding, D. learning
Step-by-step explanation:
In the context of a PVST network, different port states denote various stages a switch port undergoes within the Spanning Tree Protocol (STP). The Spanning Tree Protocol is responsible for preventing loops in the network by determining the optimal path and blocking redundant ones.
Forwarding (C): The forwarding state is when a port is actively passing data frames and functioning normally. In this state, the switch forwards frames and learns MAC addresses, crucial for its switching function.
Learning (D): In the learning state, the port prepares to enter the forwarding state. During this phase, the switch receives frames but doesn't forward them yet. Instead, it uses this state to learn MAC addresses by populating its MAC address table (CAM table).
These two states, forwarding and learning, are where the switch actively learns and processes MAC addresses and processes Bridge Protocol Data Units (BPDUs). BPDUs are used in STP to exchange information between switches, allowing them to collectively determine the topology of the network and establish the most efficient paths while preventing loops.
While other port states, like blocking, disabled, and listening, have their roles within STP in terms of loop prevention and port initialization, they aren't directly involved in learning MAC addresses or processing BPDUs in a PVST network.
Therefore the correct option is C. forwarding, D. learning