Four links between two switches establish an Eth-Trunk in manual mode, and the bandwidth of...

In an Eth-Trunk working in manual mode , multiple physical member links are bundled into one logical interface to provide higher bandwidth and link redundancy. If one of four 1 Gbit/s member links fails, the Eth-Trunk does not go down as long as at least one valid member link remains active. Therefore, statement A is correct. Since one link has failed and three member links remain available, the total available bandwidth becomes 3 Gbit/s , so statement B is also correct.

Statement C is incorrect because the traffic originally hashed to the failed link is not permanently stopped. Instead, after the link failure is detected, traffic is redistributed across the remaining active member links according to the trunk load-balancing mechanism. Statement D is also incorrect because Eth-Trunk provides link-level redundancy. Existing upper-layer sessions such as TCP are not necessarily interrupted and re-established simply because one member link fails. HCIA-Datacom emphasizes that Eth-Trunk improves reliability and bandwidth utilization by allowing traffic to continue across surviving links when a single member fails. This is one of the main advantages of link aggregation in campus and data center switching networks.

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