The short answer
Both services give you a private path from your buildings or colocation cage to one cloud. They bypass the public internet. You order a circuit from a carrier or cloud provider, terminate it at a router you control, and run BGP. The cloud side attaches the circuit to your virtual network. That is the shared idea.
The difference is in the plumbing and the ecosystem. AWS Direct Connect attaches through virtual interfaces to a VPC, a transit gateway, or public AWS endpoints. Azure ExpressRoute attaches through circuit peerings to a VNet or to Microsoft services. Pick the one that matches where most of your workloads and users live. If you run both clouds, plan for both.
Neither service is a magic private line to everything. A single circuit is a single point of failure. Both need two paths, diverse carriers, and careful route design. Both charge for capacity and data transfer. The rest is detail.
| Aspect | AWS Direct Connect | Azure ExpressRoute |
|---|---|---|
| Connection type | Dedicated port at a Direct Connect location or a hosted connection from a partner. | Circuit from a connectivity provider or ExpressRoute Direct ports at a peering location. |
| Attachment to cloud network | Private VIF to a VPC, transit VIF to Transit Gateway, public VIF to AWS public services. | Azure private peering to a VNet through an ExpressRoute gateway, Microsoft peering to Microsoft services. |
| Redundancy | Two connections at diverse locations, LAG, separate routers, BGP failover. | Two circuits from diverse providers, zone-redundant gateways, dual ExpressRoute Direct ports. |
| Encryption | Not encrypted by default; MACsec on supported dedicated connections. | Not encrypted by default; MACsec on ExpressRoute Direct. |
| Global or multi-site | Direct Connect gateway, Transit Gateway, and SiteLink for site-to-site traffic. | Global Reach connects circuits; Premium SKU supports global VNet connectivity. |
| Performance controls | Jumbo frames, LAG, public VIF, and BGP route policy. | FastPath, gateway SKU choice, route filters, and BGP route policy. |
| Monitoring | CloudWatch metrics, router logs, and BGP session state. | Network Watcher, Connection Monitor, and gateway metrics. |
How AWS Direct Connect works
You get a port at an AWS Direct Connect location, either a dedicated connection you cross-connect to, or a hosted connection from an AWS Partner. You can bundle ports into a link aggregation group for more bandwidth or redundancy. On top, you create virtual interfaces. A private virtual interface connects to a virtual private gateway on a VPC or to a Direct Connect gateway that spans VPCs. A transit virtual interface connects to AWS Transit Gateway. A public virtual interface connects to AWS public services such as S3 and DynamoDB through public IP space.
Routing is BGP. You bring your own ASN, or AWS provides one, and you advertise the prefixes you want reachable. Route limits and prefix filters matter. Plan your address plan before you order. Jumbo frames are supported on private and transit virtual interfaces, but every device on the path must agree. MACsec is available on supported dedicated connections for link encryption.
For resilience, AWS publishes reference models: development, high availability, and maximum resiliency. In practice, order two connections at different locations, from different carriers where possible, and terminate them on separate routers. Use BGP timers and monitoring. AWS Direct Connect SiteLink can send traffic between Direct Connect locations over the AWS backbone, which helps branch-to-branch traffic that would otherwise go through a region. Monitor with CloudWatch metrics and router logs.
How Azure ExpressRoute works
You order an ExpressRoute circuit from a connectivity provider or use ExpressRoute Direct for dedicated ports in an Azure peering location. The circuit has a SKU: Local, Standard, or Premium. Bandwidth is chosen at order time. You configure peerings. Azure private peering connects to VNets through an ExpressRoute gateway. Microsoft peering connects to Microsoft public services, with route filters to select what you need, such as Microsoft 365.
The gateway is a real capacity limit. Pick a gateway SKU that matches your throughput and redundancy needs; zone-redundant SKUs can survive an availability zone failure. FastPath sends traffic directly to VMs and bypasses the gateway data path, which helps for high-throughput workloads. Global Reach connects two ExpressRoute circuits, so sites can talk through the Microsoft backbone. ExpressRoute Direct supports MACsec on the physical link.
ExpressRoute circuits also use BGP. You set your ASN and advertise prefixes. Redundancy means two circuits, ideally from different providers, into two gateways or a zone-redundant gateway. Watch asymmetric routing when you mix ExpressRoute, VPN, and internet paths. Use Network Watcher and Connection Monitor to see route changes and latency. Test failover before you trust it.
When to choose AWS Direct Connect
Choose AWS Direct Connect when most of your workloads sit in AWS and you need private access to VPCs at stable latency. It fits data-heavy jobs: moving backups, analytics feeds, or media files to S3, or keeping database traffic off the internet. A public virtual interface gives you a private path to AWS public endpoints, which can simplify egress design.
It also fits hub-and-spoke AWS networks. A transit virtual interface into AWS Transit Gateway lets many VPCs share one circuit. A Direct Connect gateway lets you reach VPCs in multiple regions without building a full mesh. If you have branches that need to talk to each other through AWS, SiteLink can replace some long-haul links.
Do not choose it just because it sounds more private. It still needs encryption if your policy requires it, and it still needs a second path. If your main cloud is Azure, Direct Connect becomes a second-class path with extra hops.
When to choose Azure ExpressRoute
Choose Azure ExpressRoute when Azure is your main cloud and your users depend on Microsoft services. Private peering covers VNets. Microsoft peering covers Microsoft 365 and other Microsoft public endpoints, with route filters to keep the route table small. This is common for companies that have standardized on Microsoft 365 and want that traffic to avoid the open internet.
It fits Azure VMware Solution and SAP on Azure, where private connectivity and predictable latency matter. Global Reach connects your offices through Microsoft's backbone without sending traffic through a VNet. FastPath and zone-redundant gateways help when you need throughput and availability across zones.
Watch the gateway. A circuit can be fast, but the gateway SKU can cap throughput. Also watch route filters and BGP advertisements. A bad advertisement can pull internet traffic into the circuit or blackhole a subnet. If your main cloud is AWS, ExpressRoute is usually a secondary path.
Costs and effort to consider
Both services have three cost buckets: the cloud port or circuit, the carrier tail and cross-connect, and data transfer. AWS charges port hours and data transfer out. Azure charges for the circuit and gateway, and the provider charges for the tail. Redundant circuits double the first two buckets. Do not compare quotes on bandwidth alone. Ask about route scale, gateway throughput, and support.
The hidden cost is engineering. You need routers that can run BGP, a documented address plan, and monitoring for BGP flaps and latency. You need change control for route filters and prefix lists. You need to test failover, not just configure it. A single engineer who knows BGP can run this, but that person becomes a dependency.
Start with a small proof: one circuit, one VIF or peering, one test VPC or VNet, and a load test that pushes real traffic. Measure latency and failover time. Then decide on redundancy. The Cloudverg Expert architecture session, $450 one-time, is one option among others if you want a senior architect to review your design before you sign a carrier contract. Other options include your carrier's design team or a local network consultant.
Frequently asked questions
Is AWS Direct Connect the same as a VPN?
No. A VPN runs IPsec over the public internet. AWS Direct Connect is a private circuit into AWS. It is not encrypted by default, so add MACsec where supported or run IPsec over it.
Can I run AWS Direct Connect and Azure ExpressRoute together?
Yes. Many companies run both when they use two clouds. You need separate routers or routing instances, separate BGP sessions, and a clear address plan. Test failover between the two paths.
Do I need two circuits for redundancy?
Yes, if the link carries production traffic. One circuit, one router, or one carrier is a single point of failure. Order diverse paths and confirm that the provider does not share a conduit or device.