Final answer:
In the context of configuring a Voice VLAN on a network switch, PortFast is automatically enabled to reduce connection delays for IP phones, but BPDU Guard is not automatically disabled when the Voice VLAN is removed. The network feature PortFast bypasses usual STP steps, while BPDU Guard offers security against possible STP issues; both function independently of Voice VLAN status.
Step-by-step explanation:
When a Voice VLAN is configured, PortFast is automatically enabled; however, BPDU Guard is not automatically disabled when that same voice VLAN is disabled. PortFast is a network feature that allows devices to connect to a LAN with minimal delay, skipping the standard Spanning Tree Protocol (STP) listening and learning phase. It is especially useful for devices such as IP phones that need to start sending and receiving data as soon as they are connected.
On the other hand, BPDU Guard is a security feature that prevents potential Spanning Tree Protocol (STP) topology changes by shutting down the port that receives Bridge Protocol Data Unit (BPDU) packets when PortFast is enabled. While PortFast immediately transitions the port into the forwarding state, thereby reducing the time it takes for devices like IP phones to start functioning, BPDU Guard protects against configuration mistakes that could result in layer 2 loops.
If you disable a Voice VLAN, PortFast remains enabled unless explicitly turned off. This design decision is likely due to the reality that network administrators would want to maintain the quick network access provided by PortFast for other purposes even after the Voice VLAN is no longer in use.