LAN Switching Technologies Flashcards

A trunk link between two switches carries VLANs 1–100. Which command restricts it to carry only VLANs 10, 20, and 30?

Answer: switchport trunk allowed vlan 10,20,30

The 'switchport trunk allowed vlan' command specifies which VLANs are permitted to traverse the trunk.

Which STP port role carries the best path toward the root bridge on a non-root switch?

Answer: Root port

Each non-root switch has one root port, which is the port with the lowest-cost path to the root bridge.

What does the 'switchport mode dynamic desirable' command cause the port to do?

Answer: Actively attempt to form a trunk using DTP

'Dynamic desirable' causes the port to actively send DTP frames to negotiate a trunk with the neighbor.

Which feature prevents a non-root switch port from immediately transitioning to forwarding when it first connects, avoiding temporary loops?

Answer: Spanning Tree Protocol

STP's listening and learning states introduce a delay before forwarding to ensure a loop-free topology is established.

Two switches are connected with an EtherChannel bundle. Which load-balancing method uses both source and destination MAC addresses?

Answer: src-dst-mac

The 'src-dst-mac' load-balancing method hashes both source and destination MAC addresses to select the active link.

What is the default VTP mode on a Cisco Catalyst switch?

Answer: Server

Cisco switches default to VTP Server mode, allowing them to create, modify, and delete VLANs.

Which attack technique allows a host to send frames on a VLAN it should not access by exploiting trunk negotiation?

Answer: VLAN hopping via double tagging

Double-tagging attacks embed an inner VLAN tag that gets processed after the outer tag is stripped at the first trunk.