Quick Answer
The answer is the Multi-Exit Discriminator (MED) attribute, which is preferred when it has the lowest value. This is because the MED is a metric used to influence inbound traffic from a neighboring autonomous system (AS); a lower MED value signals to that neighbor that this path is more preferred for entering your AS, making it the decisive factor in path selection when multiple entry points exist. On the ENCOR 350-401 exam, this concept tests your understanding of BGP path selection and how MED differs from weight or local preference—common traps include confusing MED with local preference (which prefers the highest value) or forgetting that MED is only compared between paths from the same neighboring AS. To remember, think of MED as the “entrance fee” you want to be low: the lower the MED, the more attractive the door into your network.
This 350-401 practice question tests your understanding of vrf and path isolation. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which BGP attribute is preferred when it has the lowest value?
MED (Multi-Exit Discriminator)
Correct. Lower MED is preferred.
Local Preference
Why wrong: Incorrect. Higher Local Preference is preferred.
Weight
Why wrong: Incorrect. Higher Weight is preferred.
AS Path
Why wrong: Incorrect. Shorter AS Path is preferred, not lower value.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
MED (Multi-Exit Discriminator)
The Multi-Exit Discriminator (MED) is a BGP attribute used to influence inbound traffic from a neighboring AS. A lower MED value is preferred because it indicates a more preferred path into the AS, making it the correct answer when the question asks for the attribute preferred with the lowest value.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
MED (Multi-Exit Discriminator)
Why this is correct
Correct. Lower MED is preferred.
Related concept
Read the scenario before looking for a memorised answer.
Local Preference
Why it's wrong here
Incorrect. Higher Local Preference is preferred.
Weight
Why it's wrong here
Incorrect. Higher Weight is preferred.
AS Path
Why it's wrong here
Incorrect. Shorter AS Path is preferred, not lower value.
Common exam traps
Cisco often tests the confusion between attributes that prefer the lowest value (MED) versus those that prefer the highest value (Weight, Local Preference), and candidates mistakenly apply the 'lowest is best' rule to all attributes without remembering the specific behavior of each.
Detailed technical explanation
MED is exchanged between eBGP peers and is typically used in multi-homed scenarios to influence which link an external AS uses to reach the local AS. Under the hood, MED is a 4-byte unsigned integer (RFC 4271) that is compared only when paths come from the same neighboring AS (or same AS set when bgp bestpath med missing-as-worst is configured). In real-world deployments, MED values are often set to reflect IGP metrics or link bandwidth to optimize inbound traffic engineering.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
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FAQ
VRF and Path Isolation — This question tests VRF and Path Isolation — Read the scenario before looking for a memorised answer..
The correct answer is: MED (Multi-Exit Discriminator) — The Multi-Exit Discriminator (MED) is a BGP attribute used to influence inbound traffic from a neighboring AS. A lower MED value is preferred because it indicates a more preferred path into the AS, making it the correct answer when the question asks for the attribute preferred with the lowest value.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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