Configuration BPDUs are sent in three cases:
• When the Hello Timer expires (every two seconds by default), the Root Bridge originates a Configuration BPDU on every port (assuming no self-looped ports). This is a part of the normal Configuration BPDU processing.
• When non-Root Bridges receive a Configuration BPDU on their Root Port, they send (propagate) updated Configuration BPDUs on all of their Designated Ports (normal processing).
• When a Designated Port hears an inferior Configuration BPDU from another switch, it sends a Configuration BPDU of its own to suppress the less attractive information.
Was this article helpful?