What cost is assigned to a 1 Gbps link in an 802.1D STP network?

In an 802.1D Spanning Tree Protocol (STP) network, the cost assigned to a 1 Gbps link is 4. This is based on the IEEE 802.1D standard, which defines the cost values assigned to different link speeds for path selection purposes within the STP topology.

The cost metric in STP is utilized to determine the best path for data traffic based on bandwidth. As bandwidth increases, the cost is typically lower, which indicates a more preferred route for data. For a 1 Gbps link, the cost of 4 reflects the higher bandwidth of this link compared to slower speeds, leading to a lower numerical cost that signifies its efficiency.

By assigning these costs correctly, STP can effectively prevent loops in the network while ensuring that data can be routed through the most optimal paths, enhancing overall network performance and reliability.