Difference between Zone-Redundant option and AZ 1, 2, or 3 specifically

Question

What's the difference between "Zone-Redundant" option and "AZ 1, 2, or 3" options?

I need to create a redundant connection to my Express Route circuit (I'm using Ergw1AZ) but don't know which option I choose about Availability Zone:

Answer 1

@Erick Santos

Thank you for reaching out.

Thank you, Luis, for detailed answer above.

I am just providing an answer to your follow-up question and providing some additional details which I think can be helpful.

If I choose "Zone-Redundant" option, is there some need to create two or more gateways? Or just 1 zone-redundant gateway gives me the redundancy I need in that region (cause it is deployed spreaded across the AZ's)?

A Zone-redundant service is replicated or distributed across zones automatically. When you choose the zone-redundant option it automatically deploys your virtual network gateways across availability zones.

If it helps you can also go through this High availability guide for Azure Express Route This article delves into network architecture considerations for building robust network connectivity using an ExpressRoute, then let's look into the fine-tuning features that help you to improve the high availability of your ExpressRoute circuit like:

• Deploying ExpressRoute circuit in active-active mode.
• Improving failure detection time

You can also go through this new feature ExpressRoute guided portal experience for multi-site resiliency (Currently in public preview). Which makes it easier for you to configure multi-site resilient ExpressRoute circuits and connect them to a virtual network gateway. You can choose Maximum Resiliency option which provides maximum protection against location wide outages and connectivity failures in an ExpressRoute location. This option is strongly recommended for all critical and production workloads. More details here.

Hope this helps! Please let me know if you have any questions. Thank you!

Answer 2

Hi Erick Santos,

The key differences between the “Zone-Redundant” option and the “AZ 1, 2, or 3” options are:

Zone-Redundant:

• High Availability: Replicates your circuit across multiple availability zones within a region.
• Resilience: Even if one zone fails, your circuit remains operational.
• Recommended for Critical Workloads: Ideal for mission-critical applications where downtime is unacceptable.

AZ 1, 2, or 3 (Zone Specific):

• Low Latency: Places your circuit in a specific availability zone (e.g., AZ 1).
• Risk: If that specific zone (e.g., AZ 1) experiences an outage, your circuit may be affected.
• Recommended for Non-Critical Workloads: Suitable when low latency within a single zone is more important than redundancy.

References:

• https://learn.microsoft.com/en-us/azure/reliability/availability-zones-overview?tabs=azure-cli
• https://learn.microsoft.com/en-us/azure/automation/automation-availability-zones
• https://learn.microsoft.com/en-us/azure/vpn-gateway/about-zone-redundant-vnet-gateways

Cheers,

Luis

---

If the information helped address your question, please Accept the answer.