Eth-Trunk Status with Manual Load Balancing
Short answer
D The Eth-Trunk will be Down, not Up, when all member links fail.
Question
Which of the following statements is false about Eth-Trunk 1 on router A?
Key Takeaways
The main trap is confusing the state of individual member links with the aggregate Eth-Trunk interface. Students must remember that the LAG requires at least one active member to remain Up.
This question tests understanding of Eth-Trunk operational states in manual load balancing. The correct answer identifies that the trunk goes Down when all member links fail, making statement D false.
Common mistake: Students might choose B, thinking the trunk stays Up even if all links fail, or they might misread D as true because they forget that 'both disabled' means zero active members.
Expert Analysis
Eth-Trunk Membership Logic In Huawei's manual load-balancing mode, an Eth-Trunk interface (LAG) remains in the Up state as long as at least one physical member interface is Up. The Eth-Trunk does not depend on the status of the peer device's ports for its own layer 2/3 administrative state, but rather on the local aggregation group's member status.
Peer Interface Impact The question asks about the state of Eth-Trunk 1 on Router A. The options describe scenarios where interfaces on Router B are disabled. When a link on Router B goes down, the corresponding link on Router A typically transitions to Down due to link-layer protocol detection (e.g., LLDP or simple link loss). However, the Eth-Trunk on Router A only goes Down if all its member interfaces become inactive.
- Scenario A: If only G0/0/2 on Router B is disabled, G0/0/2 on Router A likely goes Down. But G0/0/1 on Router B is still active, so G0/0/1 on Router A remains Up. Since one member is Up, Eth-Trunk 1 is Up. Statement A is true.
- Scenario C: If only G0/0/1 on Router B is disabled, G0/0/1 on Router A goes Down. G0/0/2 on Router B is active, so G0/0/2 on Router A remains Up. Eth-Trunk 1 is Up. Statement C is true.
- Scenario B/D: If both G0/0/1 and G0/0/2 on Router B are disabled, both links on Router A go Down. Consequently, Eth-Trunk 1 has no active members and becomes Down.
Identifying the False Statement Statement B says Eth-Trunk 1 is Down when both peer ports are disabled. This is true because all members are down. Statement D says Eth-Trunk 1 is Up when both peer ports are disabled. This is false because there are no active members left to keep the bundle up.
The comments highlight this logical contradiction. One comment suggests D is the answer, noting that logic dictates the trunk would be down. Another user points out that if B were the false statement, it would contradict standard behavior, reinforcing that D is the incorrect assertion.
Exam Strategy
When analyzing Eth-Trunk status questions, always count the number of active member interfaces. Remember: 1+ active members = Up; 0 active members = Down. Do not get distracted by the peer device's configuration unless it directly impacts the local member status.
Frequently Asked Questions
Does the Eth-Trunk state depend on the peer device?
What happens if all member links are down?
Discussion 2 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 2
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cascartillo 👍 1 Answered DPerhaps the easiest question. It is logic that both port are down eth-trunk would be down.
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MS_RF 👍 1Yeah but then it wouldnt be D; It would be B
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