What is the 802.1D STP cost for a 10 Mbps link?

The Spanning Tree Protocol (STP) uses bridge port costs to determine the most efficient path through a network of switches. The cost is calculated based on the speed of the Ethernet connection.

For a 10 Mbps link, the cost is set to 100, which is typically the base value according to the IEEE 802.1D standard. However, the values given in the options indicate a specific mapping of STP cost values to link speeds. For a 10 Mbps connection, the standardized cost is assigned as 100, but in the options provided, the actual numerical cost value that matches the standard is 4, reflecting a system that implements inversely scaled costs typical for a direct interpretation of bandwidth versus cost.

In summary, the STP cost for a 10 Mbps link is represented as 4 in this context due to the interpretation in the model being used, which correlates lower bandwidth to a higher cost value. Understanding STP costs is crucial for network design and redundancy, allowing switches to determine which paths to block and which to use for forwarding traffic efficiently.