Question 1hardmulti select
Full question →hardmulti selectObjective-mapped
Which two conditions must match on two switch ports before they can successfully form a Layer 2 EtherChannel? (Choose two.)
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The switchport mode and VLAN settings
Correct. Access/trunk mode and related VLAN settings must match across the member links.
B
Distractor review
The STP root bridge ID on both switches
STP root bridge identity does not need to match for EtherChannel formation.
C
Best answer
The speed and duplex settings
Correct. Mismatched speed or duplex prevents proper channel formation.
D
Distractor review
The interface description
Descriptions are operationally useful but irrelevant to channel negotiation.
E
Distractor review
The ARP timeout value
ARP timeout has nothing to do with EtherChannel membership.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to incorrectly believe that the Spanning Tree Protocol (STP) root bridge ID or interface descriptions must match on both switch ports for EtherChannel formation. While STP interacts with EtherChannel bundles for loop prevention, the root bridge ID is a global network parameter and does not affect channel negotiation. Similarly, interface descriptions are purely administrative and have no impact on EtherChannel compatibility. Selecting these options can lead to confusion and incorrect answers, as the critical factors are Layer 2 port mode, VLAN settings, speed, and duplex. Understanding this distinction is essential to avoid this trap.
Technical deep dive
How to think about this question
EtherChannel is a Cisco technology that allows multiple physical Ethernet links to be combined into a single logical link to increase bandwidth and provide redundancy. For Layer 2 EtherChannel, the member ports must share consistent Layer 2 configurations to ensure the bundle operates as a single logical interface. This includes matching switchport modes (access or trunk) and VLAN settings, which guarantee that traffic is handled uniformly across all links in the channel. The formation of an EtherChannel depends on strict compatibility rules. The speed and duplex settings of the physical interfaces must be identical to prevent mismatches that cause packet loss or channel negotiation failure. Cisco switches use protocols like PAgP or LACP to negotiate and maintain the EtherChannel, and any mismatch in these critical parameters causes the channel to fail to form or to be unstable. A common exam trap is to assume that spanning tree parameters or interface descriptions must match for EtherChannel formation. While STP interacts with EtherChannel bundles, the root bridge ID does not need to be identical on both ends. Interface descriptions are purely administrative and do not affect channel negotiation. Understanding these distinctions helps avoid selecting incorrect answers and ensures proper EtherChannel deployment in real networks.
KKey Concepts to Remember
- EtherChannel bundles multiple physical Ethernet links into a single logical Layer 2 link to increase bandwidth and provide redundancy.
- All member ports in a Layer 2 EtherChannel must have matching switchport modes, such as access or trunk, to maintain consistent VLAN handling.
- Speed and duplex settings on all EtherChannel member interfaces must be identical to prevent negotiation failures and ensure stable link aggregation.
- Cisco EtherChannel protocols like PAgP and LACP rely on consistent Layer 2 configurations to successfully form and maintain channel bundles.
- Spanning Tree Protocol root bridge IDs do not need to match on both ends of an EtherChannel for the channel to form correctly.
- Interface descriptions are administrative labels and do not influence EtherChannel negotiation or operation.
- Mismatched VLAN settings or port modes across EtherChannel member ports cause the channel to fail to form or to operate improperly.
- EtherChannel requires uniform physical interface parameters to behave as a single logical link, preventing traffic loss and negotiation errors.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
EtherChannel bundles multiple physical Ethernet links into a single logical Layer 2 link to increase bandwidth and provide redundancy.
What is the correct answer to this question?
The correct answer is: The switchport mode and VLAN settings — Layer 2 EtherChannel members must have compatible Layer 2 configuration. Port mode, VLAN-related settings, speed, and duplex all need to align for the bundle to form correctly.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
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