300-410 Layer 3 Technologies Practice Question
A network engineer is implementing BGP on a Cisco IOS XE router. The router is peering with an ISP and receives a full BGP table. The engineer wants to influence inbound traffic from the ISP by making a specific prefix more preferred. The engineer has configured a route map that sets the MED to 50 for the prefix 203.0.113.0/24 and applies it outbound to the ISP. However, the ISP still prefers a different path. Which BGP attribute should the engineer manipulate to influence inbound traffic more effectively?
⚠ Common exam trap
The trap here is assuming that MED will always influence inbound traffic, but MED is often ignored by ISPs; AS_PATH prepending is more reliable.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
AS_PATH
To influence inbound traffic from an ISP, the most effective method is to manipulate the AS_PATH attribute by prepending additional AS numbers. This makes the path appear longer and less preferred. MED is often not honored by ISPs because it is an optional attribute and is only considered between autonomous systems that agree to use it. LOCAL_PREF and WEIGHT are used for outbound traffic and are not advertised externally. ORIGIN is not typically used for this purpose.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
WEIGHT
Why it's wrong here
WEIGHT is a Cisco-proprietary attribute that is locally significant and not advertised to any BGP peer. It is used to influence outbound path selection on the local router. Since it is not sent to the ISP, it cannot affect inbound traffic. Therefore, it is not useful in this scenario.
- ✗
ORIGIN
Why it's wrong here
ORIGIN is a well-known mandatory attribute that indicates the origin of the route (IGP, EGP, or incomplete). It is used in the BGP best path selection process, but it is not typically manipulated to influence inbound traffic. Moreover, changing the ORIGIN to a less preferred value (e.g., incomplete) might make the route less preferred, but it is not as effective or common as AS_PATH prepending.
- ✗
LOCAL_PREF
Why it's wrong here
LOCAL_PREF is used to influence outbound traffic from the local AS to external peers. It is a well-known discretionary attribute that is only exchanged between iBGP peers within the same autonomous system. It is not advertised to eBGP peers, so it cannot influence inbound traffic from the ISP.
- ✓
AS_PATH
Why this is correct
AS_PATH is a well-known mandatory attribute that can influence inbound traffic by making the path appear longer. By prepending additional AS numbers to the AS_PATH for a specific prefix, the engineer can make that path less preferred by the ISP. This is a common method to influence inbound traffic when MED is not honored, as MED is optional and often not considered across different autonomous systems.
Go deeper
Related to this question
About these practice questions
One of 1,401 original 300-410 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 300-410 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 300-410 exam.