hardMultiple Choice
350-401 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show bgp ipv4 unicast 10.10.10.0
BGP routing table entry for 10.10.10.0/24, version 20 Paths: (2 available, best #1, table default) Advertised to update-groups: 1 Refresh Epoch 1 65050 65100
10.0.1.2 from 10.0.1.2 (10.0.0.2)
Origin IGP, metric 0, localpref 100, weight 0, valid, external, best rx pathid: 0, tx pathid: 0x0 65050 65100 65200
10.0.1.3 from 10.0.1.3 (10.0.0.3)
Origin IGP, metric 0, localpref 100, weight 0, valid, external rx pathid: 0, tx pathid: 0x0
Based on this output, what can be concluded?
⚠ Common exam trap
Cisco often tests the AS_PATH length comparison by presenting two paths with different AS_PATH lengths but identical other attributes, expecting candidates to know that shorter AS_PATH is preferred, not longer.
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
✓
Path #1 is the best path because it has a shorter AS_PATH length.
B is correct because BGP selects the best path based on the shortest AS_PATH length when all other attributes (weight, local preference, origin) are equal. In the output, Path #1 has an AS_PATH of '65050 65100' (2 AS numbers) while Path #2 has '65050 65100 65200' (3 AS numbers), making Path #1 the best path. The 'best #1' annotation confirms this selection.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Path #2 is the best path because it has a longer AS_PATH, indicating more specific routing.
Why it's wrong here
BGP prefers the shortest AS_PATH, so the two-AS path #1 wins; a longer AS_PATH is less preferred, not more specific. The temptation is that longer prefixes are more specific in IP routing, but AS_PATH length is a path-selection metric, unrelated to prefix length.
- ✓
Path #1 is the best path because it has a shorter AS_PATH length.
Why this is correct
Path #1 wins on AS_PATH length, the fourth BGP best-path attribute after weight, local preference and locally originated routes. Its AS_PATH contains two autonomous systems (65050, 65100) versus three for path #2 (65050, 65100, 65200), so the shorter sequence is selected as best, satisfying the tie-break at that step.
- ✗
Both paths are equally preferred, and BGP uses tie-breaking rules like router ID.
Why it's wrong here
The paths are not equally preferred: path #1 has a shorter AS_PATH, so it wins before any tie-break. Router ID comparison occurs only when weight, local preference, AS_PATH, origin, MED and eBGP/iBGP preference all tie, which is not the case here.
- ✗
Path #1 is the best path because it is received from a higher IP address.
Why it's wrong here
BGP selects on attributes in a defined order, not on the neighbour's IP address; path #1 is best because its AS_PATH is shorter, and the router ID tie-break only applies after weight, local preference, AS_PATH and origin match. Higher source IP carries no preference.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.