Question 1hardmulti select
Full question →hardmulti selectObjective-mapped
Which two conditions must match for a Layer 2 EtherChannel bundle to form correctly? (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 member interfaces must use the same speed and duplex settings.
Correct. Inconsistent physical settings can prevent bundling.
B
Distractor review
Each member interface must be assigned a different native VLAN.
Native VLANs must be consistent, not different.
C
Best answer
The member interfaces must have compatible switchport mode and VLAN settings.
Correct. Trunk/access state and key VLAN settings must align.
D
Distractor review
One side must use LACP and the other must use PAgP.
Different negotiation protocols are incompatible.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that negotiation protocols can be mixed between EtherChannel peers. For instance, one side using LACP and the other using PAgP will prevent the bundle from forming, as these protocols are incompatible. Another common mistake is believing that member interfaces can have different native VLANs; however, native VLANs must be consistent across all ports in the bundle to avoid VLAN mismatches and traffic loss. These traps often lead to partial or failed EtherChannel formation, which can be difficult to diagnose without checking configuration consistency.
Technical deep dive
How to think about this question
EtherChannel is a Layer 2 technology that aggregates multiple physical Ethernet links into a single logical link to increase bandwidth and provide redundancy. This bundling requires that all member interfaces share consistent Layer 2 parameters to function correctly. Key parameters include speed, duplex, and VLAN configurations, which ensure that frames are forwarded uniformly across the bundle without causing loops or miscommunication. For an EtherChannel bundle to form successfully, Cisco devices enforce strict matching rules on member interfaces. The interfaces must have the same speed and duplex settings to avoid mismatched link characteristics that can cause packet loss or errors. Additionally, the switchport mode (access or trunk) and VLAN settings must be compatible across all member ports to maintain consistent Layer 2 forwarding behavior. These rules prevent partial bundling or interface exclusion from the EtherChannel. A common exam trap involves misunderstanding negotiation protocols or VLAN configurations. For example, mixing LACP on one side and PAgP on the other prevents bundle formation because these protocols are incompatible. Similarly, assigning different native VLANs to member interfaces disrupts trunk consistency and blocks bundling. In practical networks, mismatched settings cause EtherChannel to fail silently or degrade performance, so verifying uniform configuration is critical.
KKey Concepts to Remember
- EtherChannel bundles multiple physical Ethernet links into a single logical link to increase bandwidth and provide redundancy.
- All member interfaces in an EtherChannel must use the same speed and duplex settings to prevent link mismatches and errors.
- Switchport mode and VLAN settings must be consistent across all EtherChannel member interfaces to maintain uniform Layer 2 forwarding.
- Negotiation protocols like LACP and PAgP must match on both ends of the EtherChannel to successfully form the bundle.
- Native VLAN settings must be identical on all member interfaces to avoid VLAN mismatches that prevent EtherChannel formation.
- Inconsistent physical or Layer 2 parameters cause member interfaces to be excluded from the EtherChannel bundle.
- EtherChannel failure due to configuration mismatches can cause silent link degradation or traffic loss in production networks.
- Cisco devices enforce strict matching rules on EtherChannel member interfaces to ensure stable and predictable link aggregation.
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 link to increase bandwidth and provide redundancy.
What is the correct answer to this question?
The correct answer is: The member interfaces must use the same speed and duplex settings. — Member interfaces must have consistent Layer 2 parameters such as speed/duplex and trunk/access characteristics.
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.
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