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Routing & Switching · Foundational

Root Port (RP)

The single port on each non-root switch with the lowest cost path to the root bridge.

Definition

Tie-breakers: lowest root path cost, then lowest sender bridge ID, then lowest sender port ID (priority and number). The root bridge has no root port.

Example

show spanning-tree shows 'Root FWD' for the root port.

Exam tip

Port ID tie-breaking uses the neighbor's (sender's) port ID, not the local port number.

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