You run apps in more than one cloud. Maybe a database in AWS, a data lake in Google Cloud, and users on Microsoft 365. They all need to talk to each other, to your offices, and to the public internet.
The fabric that makes this work is multi‑cloud networking.
What is Multi-CDN Networking?
Multi‑cloud networking is the set of links, routes, policies, and tools that connect your apps and data across two or more clouds and your own sites. You use it to move traffic privately and safely, control who can reach what, and keep performance steady when parts live far apart.
If you already stitch VPCs/VNETs inside one cloud, this is the same game with extra fields. You add routes between clouds, handle different services and names, and keep security uniform.
In short: one network mindset, many clouds underneath. This is what people mean when they say multi cloud networking.
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How Multi-Cloud Networking Works
You are building predictable, private paths between workloads that live in different clouds or in your own data centers. Each building block plugs into the others to form that end-to-end fabric.
1. Private Links Into Each Cloud
Examples: AWS Direct Connect, Azure ExpressRoute, Google Partner Interconnect
- These are dedicated circuits (usually 1 Gbps, 10 Gbps, or more) that run from a carrier-neutral colocation facility into a cloud provider’s edge.
- You lease them through your telco or from the provider’s partner list. They terminate on a cross-connect in a colo rack.
- From there, you peer your router with the cloud’s edge router using BGP. The cloud advertises the VPC/VNET prefixes to you, and you advertise your on-prem or other cloud prefixes back.
- The benefit is low jitter and fixed pricing per port (vs per-GB internet egress). The drawback is that you must commit to contracts and set up cross-connects in specific data centers.
2. Encrypted Tunnels Over the Internet
Example: IPsec VPNs, WireGuard, or even SSL-based tunnels
- This is the quickest way to link two clouds or a branch to a cloud.
- Each side deploys a VPN gateway (could be AWS VPN Gateway, Azure VPN Gateway, GCP Cloud VPN, or a virtual appliance like Cisco/StrongSwan).
- You then configure IKE/IPsec to set up encryption and authentication.
- Routes are exchanged over BGP, or you can set static routes if it’s a small setup.
3. Cloud Routers and Transit Gateways
Examples: AWS Transit Gateway, Azure Virtual WAN, Google Cloud Router
- These act as routing hubs inside a cloud. Instead of manually connecting every VPC/VNET to each other, you attach them all to a central transit.
- The transit learns routes via BGP (or static attachment in smaller cases) and forwards traffic accordingly.
- They also support segmentation: you can say “dev accounts can’t talk to prod accounts,” even though both plug into the same transit.
- You then export these learned routes to your private link (Direct Connect, ExpressRoute, etc.), which carries them to your colo hub or other clouds.
4. Name Resolution and Service Discovery
Examples: AWS Route 53 Resolver, Azure Private DNS, Consul, CoreDNS
- Once networks are linked, apps still need a way to find each other by name.
- Each cloud has its own private DNS service, but by default they don’t talk across clouds.
- To fix this, you either:
- Forward DNS queries between clouds (e.g., conditional forwarding from Azure Private DNS → Route 53 Resolver), or
- Deploy a neutral DNS tier (e.g., Infoblox, Consul, or CoreDNS) that all clouds point to.
- This ensures db.prod.internal resolves no matter where the client sits. Without this, apps break even if the pipes exist.
5. Identity and Policy
Examples: Azure AD/Entra ID, Okta, AWS IAM Identity Center
- Networking alone is not enough; you need consistent access controls.
- Best practice is to federate all clouds to a central IdP (e.g., Okta or Azure AD).
- That IdP handles SSO, MFA, and group mapping. Each cloud account/project just trusts the IdP.
- On the policy side, you move toward attribute-based controls (tags/labels like env=prod, team=finance) instead of static IP whitelists.
- That way, when a service in GCP calls an API in AWS, it authenticates with workload identity and is authorized based on policy; not because it came from some subnet.
6. Hub-and-Spoke Topology With a Neutral Core
Inside each cloud, you set up a hub-and-spoke: one transit gateway (hub) with VPCs/VNETs as spokes.
- At the center, you build a neutral core hub in a carrier-neutral colo (e.g., Equinix, Digital Realty).
- This core hub hosts your physical routers or SD-WAN edge. It terminates:
- Direct Connect / ExpressRoute / Partner Interconnect circuits.
- IPsec VPNs from branches.
- Cross-cloud paths (e.g., AWS ↔ GCP).
- BGP is the glue. Each cloud advertises its prefixes, your routers advertise others, and the core hub decides the best path.
- This design makes it easy to add another cloud later: just pull a new circuit into the same hub, plug it into the routing fabric, and all your existing policies and DNS apply automatically.
Types of Multi-Cloud Networking
When you build multi cloud networking, you are really picking the type of connection that best matches your scale, budget, and control needs. Each type comes with its own trade-offs.
Multi Cloud Use Cases
You see multi-cloud networking play out in many ways:
- Disaster recovery. One cloud runs primary workloads, another stands ready to pick up.
- Data sovereignty. Keep data in the provider that meets local compliance rules while serving apps from another.
- Performance tuning. Run AI workloads in a GPU-rich cloud but keep storage where it is cheaper.
- Global scaling. Serve users in Asia from one provider and in Europe from another for faster response.
- Mergers and acquisitions. Connect systems that already run on different clouds without a costly rebuild.
Each case is about choice without compromise.
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Conclusion
Multi‑cloud networking is a set of careful choices that you can repeat with confidence. Start with a clean IP plan and a transit layer per cloud. Build multicloud connections in a neutral core. Keep identity and policy uniform. Watch costs and latency, and practice failure.
Do this, and you get the real multicloud benefits without chaos.
