Interconnecting Data Centers with VXLAN EVPN
Short answer
C EVPN meets the requirements by providing a scalable control plane for MAC route updates and loop prevention across a multi-vendor VXLAN fabric.
Question
Key Takeaways
The question tests knowledge of Layer 2 connectivity options, specifically highlighting that EVPN provides the control plane efficiency needed to prevent broadcast storms during migrations.
VXLAN EVPN is the optimal solution for interconnecting data centers to support dynamic VM migration while preventing MAC flapping and ensuring vendor neutrality.
Common mistake: Many candidates choose VXLAN alone because it handles encapsulation, but fail to recognize that EVPN is required for the routing protocol aspects like MAC route tracking and loop prevention.
Expert Analysis
Why the Answer Is Correct
EVPN (Ethernet VPN) over VXLAN is the correct choice because it separates the data plane from the control plane. While VXLAN provides the encapsulation, EVPN acts as the signaling protocol that tracks MAC address changes and distributes them to all remote devices simultaneously. This mechanism effectively prevents excessive MAC flapping and broadcast/unicast traffic loops, which are critical requirements for dynamic VM migration.
Why the Other Options Are Wrong
Option A (EoMPLS) relies on MPLS infrastructure and can introduce complexity without the specific benefits of EVPN's scalability. Option B (OTV) is a Cisco proprietary technology, which violates the requirement to use equipment from different manufacturers to avoid vendor lock-in. Option D (VXLAN) alone lacks the sophisticated control plane features of EVPN to handle MAC route updates and loop prevention efficiently in a multi-vendor environment.
Community Comment Notes
The community vote was split evenly between C and D. Some users argued that since the question mentions 'encapsulation,' VXLAN is the direct answer, stating "This is VXLAN definition." However, others correctly identified that EVPN is the superior architectural choice for the stated requirements, noting "EVPN sounds like the better option" due to its control plane capabilities. The consensus among those who understand the nuances is that EVPN solves the specific problems of flapping and simultaneous updates that plain VXLAN does not.
Official Reference
This link opens the official vendor documentation in a new tab.
Exam Strategy
When evaluating data center interconnect solutions, always distinguish between the encapsulation method (VXLAN) and the control plane protocol (EVPN). If the question emphasizes MAC mobility, loop prevention, or multi-homing, EVPN is likely the intended answer even if VXLAN is mentioned as the underlay.
Frequently Asked Questions
Why isn't VXLAN the correct answer?
Why is OTV incorrect?
Community Votes
50% of anonymous learners picked answer D. 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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missionflamingo 👍 1 Answered CEVPN sounds like the better option
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lurker8000 👍 1C. EVPN sounds correct to me
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Fcpoultry 👍 1 Answered DThis is VXLAN definition.
Reader comments & corrections
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