CCNA 200-301 Practice Test 2025 – Complete Cisco Exam Prep

The mode that results in no trunk being formed is the mode where devices are configured to actively seek a trunk link. In the case of Dynamic Auto, this mode only allows the switch to respond to trunk negotiation requests from the other side but does not initiate the requests itself. Therefore, if the other device is also in a mode that doesn’t initiate trunking, neither switch will form a trunk.

On the other hand, Dynamic Desirable actively attempts to negotiate a trunk link and, if the other side is also capable, a trunk will be formed. Access mode is explicitly designed to connect devices to a single VLAN and cannot negotiate a trunk link, but the intention behind it is to create a non-trunk link scenario. Nonegotiate, while it does not initiate trunking like Dynamic Desirable, can still form a trunk if the opposite side is in a compatible mode. Therefore, it is Dynamic Auto that specifically allows for a situation where no trunk link will be formed if the opposite side is not also in a compatible trunking mode.