The VLAN number is “8” because the configurable spanning root bridge priority value on a Cisco Catalyst switch that is closest to 8200 is 8192. When this configurable value of 8192 is subtracted from the supplied value of 8200 in the Question of the Week, the remainder is “8”. This calculation is performed due to the 802.1T structure of the Spanning Tree implementation supported on Cisco Catalyst switches. For more information, see the Cisco 360 Link-Layer Lesson Module or sign up for the NMC Live On-line Group Mentoring sessions that supplement Cisco 360 content.