Eth-Trunk Configuration Constraints and Requirements

H12-811 By islever Editorial Last updated

Ethernet Link Aggregation

Short answer

ABCD All listed statements accurately describe the requirements and limitations for configuring Huawei Eth-Trunk link aggregation.

Question

Which of the following statements about link aggregation are true? (Choose all that apply.)
  1. Devices at both ends of an Eth-Trunk must use the same link aggregation mode. Correct Answer
  2. Eth-Trunk interfaces cannot be nested. Correct Answer
  3. GE electrical interfaces and GE optical interfaces cannot be added to the same Eth-Trunk interface. Correct Answer
  4. GE interfaces and FE interfaces cannot be added to the same Eth-Trunk interface. Correct Answer

Key Takeaways

The main trap is assuming flexibility in mixed-media or mixed-speed environments; link aggregation demands strict homogeneity in mode, media type, and speed across all member interfaces.

This page explains which statements about Eth-Trunk link aggregation are true. The correct options are A, B, C, and D, covering peer mode consistency, nesting prohibitions, and media/bandwidth restrictions.

Common mistake: Candidates often select fewer than all options, mistakenly believing that GE electrical and optical interfaces can be mixed or that Eth-Trunks can be nested, leading to incorrect configuration attempts.

Expert Analysis

The question asks for the true statements regarding link aggregation, specifically focusing on Huawei's Eth-Trunk technology. To determine the correct answers, we must evaluate each statement against the operational constraints of creating a logical bundle interface.

A. Devices at both ends of an Eth-Trunk must use the same link aggregation mode. This is True. Link aggregation protocols (such as LACP or static manual mode) require consistency between peers to establish and maintain the bundle. If one side uses LACP and the other uses static, or if they are in different modes entirely, the trunk will fail to form or traffic will be dropped. Consistency is a fundamental requirement for any aggregated link.

B. Eth-Trunk interfaces cannot be nested. This is True. In standard Ethernet switching architectures, including Huawei's VRP, you cannot create an Eth-Trunk inside another Eth-Trunk. An Eth-Trunk is a logical Layer 2 or Layer 3 interface that bundles physical ports; it does not support further bundling of its own members into sub-trunks. This constraint prevents complex recursive topologies that would complicate loop prevention and load balancing.

C. GE electrical interfaces and GE optical interfaces cannot be added to the same Eth-Trunk interface. This is True. While both are Gigabit Ethernet, mixing media types (electrical copper vs. optical fiber) within a single Eth-Trunk is generally prohibited in many vendor implementations, including Huawei, due to potential differences in signal timing, error rates, and hardware limitations. The system typically requires homogeneous member interfaces to ensure uniform performance and synchronization.

D. GE interfaces and FE interfaces cannot be added to the same Eth-Trunk interface. This is True. Bandwidth mismatch is a critical factor in link aggregation. Bundling a 1 Gbps interface with a 100 Mbps interface creates significant imbalance and can lead to congestion, latency issues, and protocol failures. Most modern switches enforce strict speed matching for all member ports within a single Eth-Trunk to ensure efficient load distribution.

All four statements reflect standard best practices and technical restrictions for configuring robust link aggregations.

Exam Strategy

When answering multi-select questions on network technologies, look for absolute prohibitions ('cannot') and consistency requirements ('must'). In link aggregation, always check for three things: protocol alignment between peers, physical port compatibility (speed/media), and architectural limits (like nesting). If a statement describes a restriction that ensures stability or prevents loops, it is likely true.

Frequently Asked Questions

Can I mix LACP and static mode in an Eth-Trunk?

No, both ends of the Eth-Trunk must use the same aggregation mode (either both static or both LACP) to successfully negotiate and forward traffic.

Why can't GE electrical and optical interfaces be in the same Eth-Trunk?

Different media types may have varying signal characteristics and error rates. Mixing them can cause synchronization issues and degrade the reliability of the aggregated link.

More H12-811 FAQ →

Community Votes

A
33%
B
33%
C
17%
D
17%

33% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

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

  1. SamGamyi 👍 1
    Son todas verdaderas, ambos extremos deben tener el mismo modo de agregacion las interfaces eth-trunk no pueden ser anidadas (nombrar una eth-trunk en otra) las interfaces Ge electricas y opticas no se pueden mezclar y lo mismo pasa entre GE y Fe.
  2. HRTLKM 👍 1
    Correct answer A B D

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