What is Root Port?

In This section we will cover :

• What is Root port?
• Root port election Method.

Root Port is the port on non root bridge.It receives the best BPDU. Criteria for selecting root port is :

• Lowest sender Bridge I’d
• Lowest sender port I’dc (port No.)
• Lowest path cost to reach root bridge

(Port priority + Port number) – Port priority is by default 128 and port number is the switch interface number.

Acceptable priority values range from 0 to 240, in multiple of 16. The default port priority value is 128. Valid priority values are 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, and 240. All other values are rejected. The lower the the number, the higher the priority.