Interconnecting Data Centers with VXLAN EVPN
An engineer must interconnect two data centers to support the dynamic virtual machine migration. The data centers are currently interconnected using an IPv4 network. However, the data plane encapsulation of the underlay network is expected to change next year. To meet the VM migration requirement, the solution must track MAC route changes, update all other remote devices simultaneously and prevent excessive MAC flapping with broadcast and unicast traffic loops. The company must also use networking equipment from different manufacturers to prevent vendor-locking. Which solution meets these requirements?
Community Votes
50% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
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.
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.
Community Discussion (3 comments)
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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
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?
VXLAN provides the data plane encapsulation but lacks the native control plane features for efficient MAC route distribution and loop prevention that EVPN offers.
Why is OTV incorrect?
OTV is a Cisco proprietary technology, which conflicts with the requirement to use equipment from different manufacturers to prevent vendor lock-in.