Cisco OTV for Data Center Interconnection and VM Mobility

300-610 By islever Editorial Last updated

Evaluate options for interconnecting data centers with VXLAN EVPN Evaluate network segmentation methods using VXLAN and Cisco ACI

Short answer

B OTV is the required technology for data center interconnection that enables scalable Layer 2 extension, seamless VM mobility, and fault isolation between sites.

Question

A company runs mission-critical infrastructure in a single data center. Due to business growth, it plans to open more data centers in the coming years. A network engineer is asked to recommend a network technology for data center interconnection that allows scalability and seamless VM mobility while providing maximum security and fault isolation between data centers.
Which technology must be used to meet these requirements?
  1. TrustSec
  2. OTV Correct Answer
  3. CloudSec
  4. UDLD

Key Takeaways

The main trap is confusing security frameworks (TrustSec) or non-existent terms (CloudSec) with actual network interconnection protocols. OTV is the specific technology for L2-extended DCI with isolation.

This question tests knowledge of Cisco data center interconnection technologies. The correct answer is OTV, which extends Layer 2 domains across data centers to support VM mobility while maintaining fault isolation.

Common mistake: Candidates might choose TrustSec thinking 'security' implies segmentation, but TrustSec does not connect data centers or enable VM mobility. Others may pick CloudSec due to the word 'security', but it is not a real DCI protocol.

Expert Analysis

The question requires a technology for data center interconnection (DCI) that supports VM mobility and provides security and fault isolation. Let's analyze the options based on Cisco’s official body of knowledge:

  1. OTV (Overlay Transport Virtualization): This is Cisco’s proprietary Layer 2 extension technology designed specifically for DCI. It allows Layer 2 domains (VLANs) to span across geographically dispersed data centers, enabling seamless VM mobility without changing IP addresses or network configurations. OTV operates over an IP infrastructure and isolates failure domains by keeping MAC address learning local to each site, preventing loops and limiting the blast radius of failures. While it provides some security through encryption capabilities (IPsec), its primary design goal is L2 extension with fault isolation.
  2. TrustSec: This is a framework for software-defined segmentation using Security Group Tags (SGTs). It focuses on identity-based access control within the network, not on connecting data centers or extending Layer 2 domains for VM mobility.
  3. CloudSec: This is not a standard Cisco networking technology term for DCI. It appears to be a distractor or a generic marketing term, not a specific protocol like OTV, VXLAN, or EVPN.
  4. UDLD (UniDirectional Link Detection): This is a Layer 2 protocol used to detect and disable links that are transmitting unidirectional traffic, typically caused by fiber issues. It is a maintenance/debugging tool, not a connectivity solution for data centers.

The comment suggesting "CloudSec" is incorrect because CloudSec is not a recognized DCI technology in this context. OTV is the correct answer because it is the only option listed that is a dedicated data center interconnection technology capable of extending Layer 2 networks (for VM mobility) while providing fault isolation (by design, unlike simple bridging). Although VXLAN-EVPN is more modern, it is not an option here. Among the choices, OTV is the definitive technology for this scenario.

Therefore, the correct answer is B. The key insight is recognizing OTV as the legacy but still valid Cisco solution for L2-extended DCI with isolation.

Official Reference

https://www.cisco.com/c/en/us/products/switches/nexus-7000-series-switches/index.html

This link opens the official vendor documentation in a new tab.

Exam Strategy

When asked about Data Center Interconnection (DCI) with VM mobility, look for Layer 2 extension technologies first. If VXLAN/EVPN isn't an option, consider OTV. Eliminate security-only solutions (TrustSec) or monitoring tools (UDLD) immediately. Remember that OTV isolates failure domains, which addresses the 'fault isolation' requirement.

Frequently Asked Questions

Why is OTV better than simple bridging for DCI?

OTV isolates failure domains. In simple bridging, a loop or flap in one data center can bring down the other. OTV prevents MAC address flapping from propagating across the fabric, ensuring stability.

Does OTV support security features?

Yes, OTV supports IPsec encryption to secure the overlay traffic between data centers, meeting the security requirements mentioned in the question.

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Community Votes

B
50%
C
50%

50% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 2 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 2

  1. Ayman_B 👍 1 Answered C
    CloudSec is the right answer because it is the only technology that combines strong encryption, fault isolation, and scalability in a data center connectivity environment, making it the ideal choice for critical infrastructure.
  2. garza_javi 👍 1 Answered B
    correct

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