What is the RSTP port cost for a 100 Gbps link?

To determine the RSTP (Rapid Spanning Tree Protocol) port cost for a 100 Gbps link, it is important to refer to the cost formula that RSTP uses, which is derived from the IEEE 802.1D standard. RSTP port costs are based on the speed of the links, where lower numbers indicate higher link speeds.

The default port costs in RSTP are designed to allow the protocol to quickly determine the best path through the network. According to the standard, the cost for a 100 Gbps link is set at 200. This aligns with the predefined values specified for different link speeds, with 100 Gbps assigned a cost of 200, reflecting the overall goal of the spanning tree to find the least cost path.

Understanding how these port costs are assigned helps in configuring RSTP effectively, ensuring that the best paths are selected for data to travel through the network while maintaining redundancy and reliability. The other costs mentioned—20, 2,000, and 2,000,000—do not accurately represent the cost for a 100 Gbps link based on the established standards in RSTP calculations.