AZ-305 Design infrastructure solutions Practice Question
Your company is designing a hybrid network architecture to connect an on-premises data center to Azure. The requirements include: high availability, low latency, and cost optimization. Which TWO options should you recommend?
⚠ Common exam trap
Many candidates assume a single ExpressRoute circuit is sufficient for high availability, but Azure requires at least two circuits from different providers to meet carrier-level redundancy, as a single circuit is a single point of failure.
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
✓
ExpressRoute Gateway
ExpressRoute Gateway is correct because it provides a dedicated, private connection from on-premises to Azure, bypassing the public internet for lower latency and more consistent performance. It supports high availability through active-active configurations and can be paired with multiple circuits for redundancy, meeting the hybrid network requirements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ExpressRoute Gateway
Why this is correct
The ExpressRoute Gateway is the Azure-side virtual network gateway that terminates an ExpressRoute circuit and routes traffic between on-premises networks and Azure VNets. It provides low-latency, high-bandwidth connectivity by using a private, dedicated connection rather than the public internet, and it supports active-active mode to maintain availability even if one gateway instance fails. This is the essential component for hybrid connectivity, as it is the actual endpoint that enables traffic flow over ExpressRoute.
- ✗
Single ExpressRoute circuit
Why it's wrong here
A single ExpressRoute circuit, even one with redundant pair links, remains a single point of failure at the circuit level; if the service provider experiences an outage or the peering location fails, all connectivity between on-premises and Azure is lost. High availability requires at least two circuits—ideally from different providers and diverse paths—so that a failure in one circuit or provider does not affect the other. Thus, relying on a single circuit does not meet the high-availability requirement.
- ✗
Site-to-Site VPN
Why it's wrong here
A Site-to-Site VPN uses the public internet to tunnel traffic, which introduces inherently variable latency and is subject to internet congestion and provider outages; it also typically offers lower bandwidth compared to ExpressRoute. While it can serve as a backup or a lower-cost option, it does not provide the low-latency, high-bandwidth private connectivity that the architecture requires, so it is not the correct choice for the primary connection.
- ✗
ExpressRoute Direct
Why it's wrong here
ExpressRoute Direct provides dedicated physical ports at a peering location, allowing you to manage the port speed and create multiple circuits on the same physical infrastructure, but it does not inherently provide high availability. A single pair of Direct ports is still a single point of failure unless you have multiple Direct connections or separate circuits with path diversity. It is a feature for higher bandwidth and flexibility, not a substitute for redundant circuit design.
- ✓
Two ExpressRoute circuits from different providers
Why this is correct
Using two ExpressRoute circuits from different providers is a correct high-availability strategy because it eliminates single points of failure in the carrier network and at the peering location; if one provider fails, traffic can automatically fail over to the other. This is a best practice, but it is a redundancy architecture—not a component in itself. To implement it, you still need an ExpressRoute Gateway (in active-active mode) to connect both circuits to your virtual network, which is the required component for this hybrid design.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 practice question is part of Courseiva's free Microsoft 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 AZ-305 exam.