Inter-Chassis Eth-Trunk vs Stacked Switch Aggregation

H12-811 By islever Editorial Last updated

Short answer

B An inter-chassis Eth-Trunk is unnecessary when switches are virtualized via stacking/CSS; a standard Eth-Trunk suffices.

Question

After switches are virtualized into one logical switch using stacking or CSS, an inter-chassis Eth-Trunk can be deployed to improve network reliability.
  1. TRUE
  2. FALSE Correct Answer

Key Takeaways

The main trap is confusing Multi-Chassis LAG (for independent switches) with standard Link Aggregation (for virtualized/stacked switches).

Determine if inter-chassis Eth-Trunk is required after switch virtualization. The correct answer is FALSE because standard Eth-Trunks handle aggregated links within a logical stack.

Common mistake: Choosing TRUE because students associate 'inter-ch/trunk' with reliability improvements without realizing that virtualization changes the architectural requirement from MC-LAG to internal stack port-channeling.

Expert Analysis

The question asks whether an inter-chassis Eth-Trunk is deployed after switches are virtualized into one logical switch using stacking or CSS. This requires distinguishing between standard link aggregation and multi-chassis link aggregation protocols.

When switches are stacked (iStack) or clustered (CSS), they form a single logical device with a unified control plane. In this scenario, you can configure a standard Eth-Trunk where member interfaces reside on different physical chassis. The logical switch handles the distribution of traffic across these members seamlessly because it views all ports as part of itself. There is no need for a separate inter-chassis protocol because the "inter-chassis" aspect is handled internally by the stack/cluster fabric.

An Inter-Chassis Eth-Trunk (often referred to as E-Trunk or MC-LAG in other vendors' terms) is specifically designed for scenarios where two switches remain independent entities but need to appear as a single LACP endpoint to a downstream device. Since the premise states the switches are already virtualized into one logical switch, deploying an inter-chassis Eth-Trunk is redundant and technically incorrect terminology for that specific topology. Therefore, the statement is false because the correct mechanism is a standard Eth-Trunk, not an inter-chassis variant.

The comment arguing for FALSE correctly identifies that once virtualized, normal Eth-Trunks suffice, making the 'inter-chassis' distinction unnecessary.

Exam Strategy

Always check the state of the network devices before selecting a configuration option. If devices are 'virtualized', 'stacked', or 'clustered', look for standard local aggregation commands. If devices are 'independent' but require high availability, look for multi-chassis protocols like E-Trunk or M-LAG.

Frequently Asked Questions

What is the difference between iStack and CSS?

iStack (Intelligent Stack) is typically used for access and aggregation layer switches, while CSS (Cluster Switch System) is used for high-end core switches. Both virtualize multiple physical switches into one logical device.

When should I use E-Trunk instead of Eth-Trunk?

Use E-Trunk (Inter-Chassis Eth-Trunk) when connecting to a downstream device from two independent switches that are NOT stacked. Use standard Eth-Trunk when the switches are already part of a single logical stack.

More H12-811 FAQ →

Community Votes

A
50%
B
50%

50% 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. Fmoura17 👍 1 Answered A
    Explanation: When multiple physical switches are virtualized into a single logical switch using: iStack (Intelligent Stack) — for Huawei S-series access/aggregation switches CSS (Cluster Switch System) — for Huawei high-end core switches They appear as one logical device to the network. This allows the deployment of inter-chassis Eth-Trunk (link aggregation) across the physical switches, which significantly improves network reliability.
  2. e9b92a4 👍 1 Answered B
    B. FALSE Why: An inter‑chassis Eth‑Trunk (a.k.a. MC‑LAG/E‑Trunk) is used to aggregate links across two independent switches that are not virtualized. If the switches have already been virtualized into a single logical switch using stacking/CSS, you simply use a normal Eth‑Trunk with member links on different physical chassis—there’s no need (and no point) to deploy an inter‑chassis Eth‑Trunk in that case.

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