CCNA Switching and Network Access Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  The link roles are mismatched, so VLAN traffic will not be handled as intended across the link.

  Why this is correct

  When one side is a trunk and the peer is an access port, the link's encapsulation expectations conflict: the trunk port transmits 802.1Q-tagged frames while the access port accepts only untagged frames, so the access port typically drops or misplaces that traffic into its native VLAN. This logical mismatch means the VLAN traffic cannot traverse the link correctly, even though the physical link stays up.

• ✗

  The access side automatically becomes a routed port.

  Why it's wrong here

  A switchport configured as access does not dynamically become a routed port; a routed port is created by issuing the `no switchport` command at the interface level, which removes Layer 2 switching entirely. This option is tempting because in a routed-access design, an access port can be assigned an IP address and participate in routing, but that still requires explicit `no switchport` configuration, not a trunk-to-access mismatch. The correct scenario for a routed port is when a switch interface connects directly to a router or a host needing Layer 3 termination, not when a trunk and access mode conflict on the same link.

  When this WOULD be correct

  In a different scenario where the question specifies that a switchport is configured as an access port and is connected to a Layer 3 switch that is set to route traffic, the access port could be considered a routed port if the switch is configured to route traffic from that port.

• ✗

  The switches automatically synchronize their configurations.

  Why it's wrong here

  Cisco switches do not auto-synchronize running or startup configurations when encountering a port mismatch; there is no protocol that negotiates trunk/access compatibility on a point-to-point link unless DTP is used, but DTP only negotiates trunking and does not copy configs. Without VTP, which is limited to VLAN database propagation, the mismatch persists until an administrator manually reconfigures one side to match the other.

  When this WOULD be correct

  In a different scenario where two switches are connected and both are set to automatically synchronize their configurations, a question might ask about the behavior of switches when connected with mismatched port types. In that case, if both switches support a configuration synchronization feature, the option could be correct.

• ✗

  The mismatch forces OSPF to choose a new router ID.

  Why it's wrong here

  OSPF's router-ID selection is a Layer 3 process that considers loopback interfaces, an explicitly configured `router-id`, or the highest numeric IPv4 address on up/up interfaces; it has no dependency on an interface's Layer 2 switchport mode. A trunk/access mismatch on a switchport does not alter IP addressing or routing process participation, so it never triggers a new router-ID election.

  When this WOULD be correct

  In a different scenario where the question specifies that OSPF is configured on both switches and that the port configurations impact OSPF adjacency, a mismatch could lead to OSPF recalculating the router ID due to changes in the network topology.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Go deeper

Related to this question