All ports are members of VLAN 10. Considering the default cost of upstream bridges to the root bridge is equal, which option will be the new root port for VLAN 10?

Refer to the exhibit.

All ports are members of VLAN 10. Considering the default cost of upstream bridges to the root bridge is equal, which option will be the new root port for VLAN 10?
A . interface f0/13
B . interface f0/14
C . interface f0/15
D . interface f0/21

View Answer

Answer: D

Explanation:

Root Port election on each bridge Each (non-Root) bridge has exactly one Root Port, which represents the best path to the Root Bridge. Total Path Cost to root – lowest prevails (local Root Port cost added o upon receipt of Configuration BPDUs on that port, from the direction of Root Bridge) Connected Bridge ID – lowest prevails o Connected Port ID (Port Priority + Port#) – lowest prevails o Local Port ID ­lowest prevails o In this case, fa0/21 has the lowest cost, so it will be the root port.

Reference: https:// community.extremenetworks.com/extreme/topics/802_1d_spanning_tree_election_rules