The answer is to configure 'channel-group 1 mode desirable' on the physical ports. This is correct because PAgP mode desirable actively sends PAgP packets to negotiate the EtherChannel, meaning the local switch will form the channel only if the neighboring switch responds with PAgP in either desirable or auto mode, ensuring a negotiated rather than forced link. On the ENCOR 350-401 exam, this tests your understanding of the two PAgP modes—desirable and auto—where desirable actively initiates negotiation while auto passively waits, making desirable the only choice when you need to guarantee the neighbor is also using PAgP. A common trap is confusing PAgP desirable with LACP active, but remember: PAgP is Cisco proprietary and uses the mnemonic “PAgP Desirable = Proactive,” while LACP uses “Active” for the same initiating role. For exam day, just recall that if you want to ensure both sides speak PAgP, you must set the local side to desirable so it actively asks for a partner.
350-401 EtherChannel Practice Question
This 350-401 practice question tests your understanding of etherchannel. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer is configuring an EtherChannel between two Cisco switches. The engineer wants to use PAgP and ensure that the channel forms only if the neighboring switch is also configured for PAgP. Which mode should be configured on the local switch?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure 'channel-group 1 mode desirable' on the physical ports.
The correct answer is 'desirable' because it actively negotiates with the neighbor. The wrong answers either use LACP or force the channel without negotiation.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Configure 'channel-group 1 mode desirable' on the physical ports.
Why this is correct
Correct because PAgP desirable mode actively negotiates with the neighbor to form the channel.
Configure 'channel-group 1 mode auto' on the physical ports.
Why it's wrong here
Incorrect because auto is a PAgP mode that passively waits for negotiation, but it may not form if the neighbor is also auto.
✗
Configure 'channel-group 1 mode active' on the physical ports.
Why it's wrong here
Incorrect because active is an LACP mode, not PAgP.
✗
Configure 'channel-group 1 mode on' on the physical ports.
Why it's wrong here
Incorrect because 'on' forces the channel without negotiation, so it does not require the neighbor to use PAgP.
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
OSPF neighbours must agree on key parameters.
Router ID selection can affect neighbour relationships and LSDB output.
OSPF cost influences the preferred path.
A route can appear in OSPF information but not become the installed route.
TExam Day Tips
→Check area mismatch first when OSPF adjacency fails.
→Review passive interfaces when a network is advertised but no neighbour forms.
→Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 350-401 OSPF questions on adjacency and route selection.
EtherChannel — This question tests EtherChannel — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Configure 'channel-group 1 mode desirable' on the physical ports. — The correct answer is 'desirable' because it actively negotiates with the neighbor. The wrong answers either use LACP or force the channel without negotiation.
What should I do if I get this 350-401 question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 350-401 OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.