How to Configure Cost-Effective Cross-Cloud Interconnect for Google Cloud?

You are configuring a Cross-Cloud Interconnect connection for your Google Cloud organization with two public cloud service providers (CSPs)–CSP 1 and CSP 2. The CSP 1 and CSP 2 environments are closest to Frankfurt, Germany. You can choose between two common colocation locations, Frankfurt and Munich. Your organization's Google Cloud infrastructure is deployed in the North American region, us-east4, which is located in Virginia, USA. The VPC dynamic routing mode has been set to GLOBAL. Your organization requires 20 Gbps of protected bandwidth with a 99.9% Google Cloud SLA. You want to minimize costs where possible. What should you do?

  1. 1. Create two Cross-Cloud Interconnect connections to CSP 1, with 40 Gbps of total bandwidth (20 Gbps in zone 1 and 20 Gbps in zone 2) in a common co-location facility located in Frankfurt, Germany. Source Reference Answer
  2. 1. Create two Cross-Cloud Interconnect connections to CSP 1, with 20 Gbps of total bandwidth (10 Gbps in zone 1 and 10 Gbps in zone 2) in a common co-location facility located in Frankfurt, Germany.
  3. 1. Create two Cross-Cloud Interconnect connections to CSP 1, with 40 Gbps of total bandwidth (20 Gbps in zone 1) in a common co-location facility located in Frankfurt, Germany and (20 Gbps in zone 2) in a common co-location facility located in Munich, Germany.
  4. 1. Create two Cross-Cloud Interconnect connections to CSP 1, with 40 Gbps of total bandwidth (20 Gbps in zone 1 and 20 Gbps in zone 2) in a common co-location facility located in Frankfurt, Germany.

Community Votes

A
67%
B
33%

67% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Community Insight

The question tests understanding of protected bandwidth calculation and cross-zone redundancy versus geographic distribution, with the common trap being over-provisioning across multiple cities instead of leveraging local edge availability zones.

This question tests optimal configuration of Google Cloud Cross-Cloud Interconnect for high availability and bandwidth requirements while minimizing costs. The community consensus confirms deploying dual 20 Gbps connections in a single nearby colocation facility meets the 99.9% SLA and protected bandwidth goals efficiently.

Option B is the most frequent incorrect choice because candidates mistakenly calculate total bandwidth as the sum of individual connection speeds rather than recognizing that each connection must independently meet the full protected bandwidth requirement for true redundancy and SLA compliance.

Community Discussion (3 comments)

mohitms1996 👍 1 Selected: B
Bandwidth + Redundancy: You need 20 Gbps of protected bandwidth, which means two 10 Gbps connections (one per zone) per CSP is sufficient when protected with redundancy. Google Cloud achieves 99.9% SLA when connections are deployed in redundant pairs (HA) across different edge availability zones. Location: Both CSP 1 and CSP 2 are closest to Frankfurt → no need to use Munich, which would increase complexity and cost. Though your GCP infra is in us-east4 (Virginia), your Cloud Router must be located in the same region as the VLAN attachments (i.e., europe-west3, Frankfurt), which is where the interconnects terminate. Routing mode: With Global dynamic routing, prefixes learned from europe-west3 will be available in us-east4, so you don’t need to place the Cloud Router in us-east4 (which would actually not work due to region mismatch).
Gwendal 👍 1 Selected: A
https://cloud.google.com/network-connectivity/docs/interconnect/concepts/cci-overview#minimum-requirements
1f01b87 👍 1 Selected: A
Option A is the correct answer

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Expert Analysis

Why the Answer Is Correct

Deploying two 20 Gbps connections within the same colocation facility provides the required 20 Gbps of protected bandwidth while ensuring high availability across separate edge availability zones. Each link operates independently, so if one fails, the other maintains the full 20 Gbps throughput, satisfying the 99.9% SLA. Choosing Frankfurt over Munich minimizes latency and eliminates unnecessary cross-regional fees, directly addressing the cost-minimization requirement. This configuration aligns with Google Cloud’s best practices for Cross-Cloud Interconnect deployments.

Why the Other Options Are Wrong

Option B only allocates 10 Gbps per connection, which falls short of the 20 Gbps protected bandwidth threshold when a single link fails, violating the SLA guarantee. Option C unnecessarily spans two geographic locations, increasing operational complexity and transit costs without improving redundancy since both colocations serve the same regional edge. Option D appears identical to A in the provided text but would be considered redundant in an actual exam context; however, A remains the standard validated configuration.

Community Comment Notes

Candidate Ba argues for Option B, emphasizing that two 10 Gbps links provide sufficient aggregate bandwidth, though this overlooks the strict definition of protected bandwidth where each path must sustain the full requirement. Multiple voters support Option A, citing the official documentation link that outlines minimum requirements for Cross-Cloud Interconnect redundancy. The discussion highlights a recurring debate between aggregate vs. protected bandwidth interpretation in cloud networking exams.

Official Reference

https://cloud.google.com/network-connectivity/docs/interconnect/concepts/cci-overview#minimum-requirements

Exam Strategy

Always interpret protected bandwidth as the capacity a single surviving link must maintain during a failure, not the combined speed of all active links. When minimizing costs, prioritize colocating connections in the nearest available facility rather than distributing them geographically unless explicit multi-region resilience is mandated.

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