Company GHI consolidated their network distribution so twelve network VLANs would be available over dual fiber links to a modular L2 switch in each of the company's six IDFs. The IDF modular…

Question

Options

• AThreat: 802.1q trunking attack
• BThreat: Bridge loop
• CThreat: VLAN hopping
• DThreat: VLAN hopping

• A
  13% (7)
• B
  50% (26)
• C
  29% (15)
• D
  8% (4)

Explanation

In a Layer 2 switched environment with redundant physical links (dual fiber) and no loop prevention mechanism, bridge loops (switching loops) pose the greatest threat. When multiple active paths exist between L2 switches, broadcast frames can circulate indefinitely, exponentially multiplying traffic and causing a broadcast storm that can saturate all links and crash switches within seconds - a complete network outage. The remediation is to implement Spanning Tree Protocol (STP) or a modern variant (RSTP/MSTP) which detects redundant paths and logically blocks one path while keeping it available for failover. Options A, C, and D involve VLAN hopping attacks, which are security threats but require attacker access and cause targeted data exposure rather than immediate, catastrophic network-wide failure. The redundant dual-fiber topology described makes a bridge loop the most impactful unmitigated threat in this specific design.

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