Question

A network administrator has configured an EtherChannel between two switches that are connected via four trunk links. If the physical interface for one of the trunk links changes to a down state, what happens to the EtherChannel?

A) The EtherChannel will transition to a down state.
B) Spanning Tree Protocol will recalculate the remaining trunk links.
C) The EtherChannel will remain functional.
D) Spanning Tree Protocol will transition the failed physical interface into forwarding mode.

Answer 1

If a physical interface in an EtherChannel goes down, the EtherChannel remains functional, as it is designed to handle such failures. Spanning Tree Protocol does not recalculate unless there are topology changes outside of EtherChannel.

Step-by-step explanation:

When an EtherChannel is configured between two switches via trunk links, its purpose is to provide redundancy and increased bandwidth. If one of the physical interfaces in this EtherChannel goes down, the correct answer to what happens next is C) The EtherChannel will remain functional. EtherChannel is designed to tolerate the failure of one or more links without losing the entire channel. As long as at least one of the links in the EtherChannel remains up, the logical connection will continue to pass traffic.

Spanning Tree Protocol (STP) is not directly involved in this scenario because EtherChannel has its own mechanisms to deal with link failures. STP would only recalculate if there were changes in the topology outside of the EtherChannel links. As for option D), Spanning Tree Protocol will not transition the failed physical interface into forwarding mode because that interface is down, and it cannot forward traffic until it is repaired and brought back online.