Network AccessDifficulty 3/5
An engineer configures channel-group 1 mode active on switch A and channel-group 1 mode auto on switch B. What happens?
- AA static EtherChannel forms
- BAn LACP EtherChannel forms
- CA PAgP EtherChannel forms
- DNo EtherChannel forms because active is LACP and auto is PAgP
Show answer and rationale
Correct: D. 'active' and 'passive' are LACP modes; 'desirable' and 'auto' are PAgP modes. Mixing protocols prevents negotiation, so the bundle never forms and the links operate individually (STP may block one).
- B — LACP needs active/active or active/passive on both sides.
- C — PAgP needs desirable/desirable or desirable/auto.
- A — Static requires mode on at both ends.