Administrative Distance for Internal BGP Routes
Short answer
D Internal BGP routes have an administrative distance of 200, making them less preferred than routes from protocols with lower ADs like eBGP (20) or OSPF (110).
Question
Key Takeaways
The question tests knowledge of specific Administrative Distance values, with the main trap being confusion between Internal BGP (200) and External BGP (20).
Learn why internal BGP routes have an administrative distance of 200. This guide explains AD values for common routing protocols including eBGP, OSPF, and EIGRP.
Common mistake: Many candidates mistakenly choose 20, which is the AD for External BGP (eBGP), rather than Internal BGP (iBGP).
Expert Analysis
Administrative Distance (AD) is a Cisco-defined metric used by routers to select the best path when multiple routing protocols provide routes to the same destination. Each protocol is assigned a default AD value, where lower numbers indicate higher trustworthiness.
Internal BGP (iBGP) has an administrative distance of 200. This high value reflects that iBGP peers are typically within the same autonomous system and do not carry the external trust context of eBGP. Consequently, if both iBGP and other protocols like OSPF or EIGRP offer paths, the router will prefer the lower-AD protocol unless policy dictates otherwise.
Let's review the other options:
- 20 is the AD for External BGP (eBGP), which is trusted more than iBGP because it comes from outside the local AS.
- 110 is the AD for OSPF, a popular Interior Gateway Protocol (IGP).
- 170 is the AD for Internal EIGRP, another IGP.
The comment suggesting 'A' (20) confuses internal with external BGP. The comment supporting 'D' (200) is correct. Understanding these specific values is crucial for troubleshooting route selection in multi-protocol environments.
Exam Strategy
Memorize the standard Administrative Distance values for major routing protocols. Focus on distinguishing between Internal and External BGP (200 vs 20) as this is a frequent exam trap. When troubleshooting route preference, always check the AD first if multiple protocols are active.
Frequently Asked Questions
Why does Internal BGP have a higher administrative distance than External BGP?
Which routing protocol has an administrative distance of 110?
Community Votes
34% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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rf18 👍 3 Answered Dthe answer is D. 200. i cant with this bot below :)
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AnderSpain 👍 1 Answered AAdministrative Distance (AD): This is the metric routers use to determine the reliability of a routing protocol. The lower the number, the higher the priority and trust the router assigns to that route.
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Skri113xX 👍 1 Answered BIs B the consensus here? It seems right to me.
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