Modern cloud computing depends on far more than virtual machines and data centers. Behind every application hosted on AWS, Microsoft Azure, or Google Cloud is a massive cloud network architecture designed to move traffic between users, regions, availability zones, private networks, and on-premises infrastructure.
Understanding this architecture is especially important for network engineers, cloud architects, DevOps engineers, and system administrators. When an application spans multiple regions—or even multiple cloud providers—the way traffic is routed can directly affect latency, availability, security, and cost.
This guide explains how cloud networking works and examines how AWS, Azure, and Google Cloud build and expose their global networking infrastructure. Instead of simply comparing product lists, we will focus on the networking concepts behind VPCs, VNets, backbone networks, routing, hub-and-spoke architectures, hybrid connectivity, and multicloud design.
If you are new to the cloud itself, start with our Cloud Computing Explained guide before moving into the networking architecture covered here.
Cloud network architecture describes the combination of physical and virtual networking infrastructure that connects cloud workloads, users, data centers, regions, and external networks.
At a simplified level, the architecture can be visualized as:
Users → Edge Network → Cloud Backbone → Region → Virtual Network → Subnet → Workload
The physical layer contains routers, switches, fiber-optic links, submarine cables, edge locations, and data centers.
Above that infrastructure sits a software-defined networking layer. This allows customers to create isolated virtual networks without having to manage the provider’s physical routers and switches.
Depending on the provider, these networks have different names:
| Provider | Primary Virtual Network |
|---|---|
| AWS | Amazon VPC |
| Microsoft Azure | Virtual Network (VNet) |
| Google Cloud | VPC Network |
Although the terminology differs, all three platforms allow engineers to define IP address ranges, subnets, routes, firewall policies, gateways, and connectivity to other networks.
This is essentially the cloud evolution of many concepts covered in our Computer Networking Explained guide.
One of the most important concepts in cloud networking is the global backbone network.
A backbone is a high-capacity network connecting geographically distributed infrastructure.
Instead of relying entirely on the public internet to move traffic between cloud regions, major providers operate extensive private networking infrastructure.
Microsoft, for example, describes the Microsoft global network as a WAN connecting its data centers and edge locations. Microsoft says its backbone spans more than 500,000 miles and connects Azure regions and other Microsoft services.
Google similarly allows enterprise networks to use Google’s network for connectivity through technologies such as Network Connectivity Center, Cloud Interconnect, and Cloud VPN.
AWS exposes its global networking infrastructure through services including Amazon VPC, Transit Gateway, Direct Connect, CloudFront, and inter-Region connectivity.
This creates an important architectural distinction:
The internet connects users to cloud infrastructure, while provider backbone networks can carry significant portions of traffic inside the provider’s own network.
The exact traffic path depends on the service, configuration, routing policy, and connectivity method being used.
AWS networking is primarily organized around the Amazon Virtual Private Cloud (VPC).
A VPC provides an isolated logical network in which AWS resources such as EC2 instances, load balancers, databases, and containers can operate.
A simplified architecture looks like this:
Internet
|
Internet Gateway
|
AWS VPC
|
+-----------------------+
| Public Subnet |
| Load Balancer |
+-----------------------+
|
+-----------------------+
| Private Subnet |
| Application Servers |
+-----------------------+
|
+-----------------------+
| Database Subnet |
| Database Servers |
+-----------------------+Each VPC has an IP address range, normally expressed as a CIDR block.
For example:
10.10.0.0/16This can then be divided into smaller subnets:
10.10.1.0/24 Public subnet
10.10.10.0/24 Application subnet
10.10.20.0/24 Database subnetRouting tables determine where packets should go.
This model will be familiar if you have already worked with Linux policy routing, VLANs, or conventional enterprise routers. CorgiNetwork’s guide to Linux traffic using the wrong interface demonstrates why understanding routing decisions remains important even when infrastructure moves into the cloud.
Connecting two VPCs is relatively straightforward.
Connecting dozens or hundreds of VPCs individually becomes much more complicated.
Imagine five VPCs:
VPC-A
VPC-B
VPC-C
VPC-D
VPC-EBuilding direct relationships between every network can create an increasingly difficult topology to operate.
AWS provides Transit Gateway as a centralized transit architecture.
According to the official AWS Transit Gateway documentation, a Transit Gateway acts as a network transit hub connecting VPCs and on-premises networks.
The architecture becomes:
VPC-A
|
VPC-B --- Transit --- VPC-C
Gateway
/ \
VPC-D VPC-EAWS describes Transit Gateway as operating at Layer 3 and routing packets toward attachments according to destination IP addresses. Transit Gateway route tables can also be used to separate routing domains—for example, isolating development networks from production networks.
That makes the model conceptually similar to routing segmentation used in traditional enterprise networks.
Microsoft Azure uses Azure Virtual Network, commonly called VNet, as the foundation of private cloud networking.
A basic architecture may look like:
Azure VNet
|
+-- Frontend Subnet
|
+-- Application Subnet
|
+-- Database Subnet
|
+-- Management SubnetVNets provide isolated IP address spaces and can be connected through several mechanisms.
One important option is VNet Peering.
Peering allows two virtual networks to communicate privately. Microsoft explains in its Azure networking architecture documentation that virtual network peering uses Microsoft’s backbone infrastructure, while more advanced designs can use gateways or hub-and-spoke architectures.
However, direct peering between large numbers of VNets can eventually become operationally complex.
This leads to the hub-and-spoke model.
A hub-and-spoke topology centralizes shared network services.
For example:
Spoke VNet
|
|
Spoke VNet ---- HUB ---- Spoke VNet
|
|
Spoke VNetThe hub may contain services such as:
The spokes contain application workloads.
This model provides centralized control without placing every workload inside one giant virtual network.
For larger environments, Microsoft provides Azure Virtual WAN.
The Azure Virtual WAN architecture can connect virtual networks, branch offices, VPN connections, ExpressRoute connectivity, and multiple regional hubs.
When multiple Virtual WAN hubs are involved, inter-hub traffic can traverse Microsoft’s global backbone.
The underlying Azure architecture becomes particularly interesting when workloads span regions.
Microsoft’s global network connects its data centers and edge infrastructure using a large private WAN.
Traffic entering Microsoft’s network can therefore be transported across Microsoft’s backbone instead of depending on a sequence of unrelated internet transit networks for the entire path.
A simplified example could look like:
User
|
Azure Edge
|
Microsoft Global Network
|
Azure Region
|
VNet
|
ApplicationThis architecture helps Microsoft control more of the end-to-end network path.
For enterprises connecting physical infrastructure to Azure, technologies such as ExpressRoute provide private connectivity into Microsoft’s network.
Google Cloud approaches virtual networking somewhat differently.
One particularly important concept is that a Google Cloud VPC network is a global resource, while subnets are regional.
Conceptually:
Global VPC
|
+-- US Subnet
|
+-- Europe Subnet
|
+-- Asia SubnetThis design can simplify some global architectures because resources in multiple regions can participate in the same VPC network.
Google provides a broader set of networking services around this model, including Cloud Router, Cloud VPN, Cloud Interconnect, Network Connectivity Center, Cloud Load Balancing, and Network Intelligence Center.
The official Google Cloud networking documentation provides the current service architecture and connectivity options.
For large hybrid and multicloud environments, Google provides Network Connectivity Center (NCC).
NCC uses a hub-and-spoke management model.
A simplified architecture looks like:
VPC A
|
On-Prem ---- NCC Hub ---- VPC B
|
Cloud VPN
|
Branch SiteAccording to Google’s Network Connectivity Center documentation, NCC can connect VPC networks and hybrid connectivity resources through a centralized hub architecture.
Google also documents the ability to use its network for site-to-site data transfer between external locations.
For example:
New York Office
|
Google Network
|
+------+------+
| |
Tokyo Sydney
Office OfficeThe exact implementation can use services such as Cloud VPN, Cloud Interconnect, and NCC.
The three providers solve many of the same fundamental problems but expose their architectures differently.
| Architecture Area | AWS | Azure | Google Cloud |
|---|---|---|---|
| Virtual Network | VPC | VNet | VPC |
| Central Transit | Transit Gateway | Virtual WAN | Network Connectivity Center |
| Dedicated Hybrid Connectivity | Direct Connect | ExpressRoute | Cloud Interconnect |
| VPN | Site-to-Site VPN | VPN Gateway | Cloud VPN |
| Dynamic Routing | BGP-supported services | BGP-supported services | Cloud Router/BGP |
| Global Provider Network | AWS global infrastructure | Microsoft global network | Google global network |
For a broader service-level comparison, see our existing AWS vs Azure vs Google Cloud comparison.
The important lesson is that choosing a cloud provider based only on virtual machine pricing ignores a significant part of cloud architecture.
Network design can be just as important as compute design.
One of the first decisions in cloud architecture is whether an application should remain regional or operate across multiple regions.
A regional architecture might look like:
Users
|
Load Balancer
|
Region A
|
Application
|
DatabaseThis is relatively simple.
A multi-region architecture introduces additional considerations:
Users
|
Global Routing
/ \
Region A Region B
| |
App A App B
\ /
Data LayerNow architects must consider:
Cloud networking therefore cannot be designed independently from application architecture.
Most enterprises do not migrate everything into the cloud at once.
Instead, environments often look like:
Corporate Data Center
|
|
Private Connectivity
|
Cloud NetworkEach provider offers dedicated connectivity technologies.
AWS provides Direct Connect.
Azure provides ExpressRoute.
Google Cloud provides Cloud Interconnect.
Google describes Cloud Interconnect as a way to extend external networks into Google’s network through dedicated or partner connectivity, with options including Dedicated Interconnect, Partner Interconnect, and Cross-Cloud Interconnect.
Hybrid networking often uses BGP to exchange routes dynamically between cloud and on-premises routers.
This means that traditional networking knowledge remains extremely valuable in cloud environments.
Concepts such as:
do not disappear in the cloud.
They simply move into software-defined infrastructure.
For example, asymmetric routing can still cause serious problems in virtualized environments. Our guide to Linux rp_filter and asymmetric routing explains one of the Linux-side mechanisms that can affect such designs.
A multicloud environment uses services from more than one cloud provider.
For example:
Enterprise Network
|
Global WAN / SD-WAN
/ | \
AWS Azure GCPThere are several ways to build this architecture.
One option is to connect each provider independently to the enterprise WAN.
Another is to use VPN connections.
Large environments may use dedicated interconnects, carrier networks, SD-WAN platforms, or specialized cloud networking platforms.
Google Cloud, for example, provides Cross-Cloud Interconnect options as part of its Cloud Interconnect portfolio.
The architectural challenge is not simply establishing connectivity.
The real challenge is maintaining:
consistent routing, security, observability, DNS, segmentation, and failure handling across several independent clouds.
Suppose an organization advertises the same or overlapping network ranges through multiple paths.
Routing can quickly become unpredictable.
For example:
10.20.0.0/16
|
+--- AWS
|
+--- On-PremisesOverlapping CIDR ranges complicate routing and may require redesign, NAT, or specialized network appliances.
The same fundamental issue appears on Linux hosts with multiple network interfaces.
CorgiNetwork’s guide to Linux ARP flux with multiple NICs on the same subnet demonstrates how multiple interfaces and ambiguous paths can produce unexpected network behavior.
Similarly, our Netplan multiple default routes and policy routing guide explains how policy routing can control traffic when a system has multiple possible gateways.
These principles become even more important when network paths span data centers and multiple cloud providers.
Connectivity alone is not enough.
Every cloud network architecture needs security controls at several layers.
A simplified model is:
Internet
|
Edge Security
|
Cloud Firewall
|
Load Balancer
|
Application Network
|
Workload SecurityModern architectures may combine:
Network visibility is particularly important because cloud environments can change far faster than traditional physical networks.
For a deeper look at monitoring malicious network activity, see our Intrusion Detection and Prevention Systems guide.
Security events from network infrastructure can also be centralized into a SIEM platform. Our SIEM Explained guide covers the role of centralized security monitoring and event correlation.
Modern cloud networks are increasingly created through code rather than manually through web dashboards.
A cloud network might include:
VPC
Subnets
Route Tables
NAT Gateway
VPN
Firewall Rules
Load Balancer
Transit Gateway
MonitoringInstead of configuring every component manually, infrastructure teams can define the architecture declaratively.
This approach is known as Infrastructure as Code (IaC).
It improves repeatability and makes infrastructure changes easier to review, version, automate, and reproduce.
For a complete introduction, read our Infrastructure as Code Explained.
This naturally leads to tools such as Terraform and cloud-native deployment frameworks, which we will cover in dedicated CorgiNetwork guides.
A production cloud network should normally begin with the architecture rather than individual cloud services.
Start by answering several questions.
For example:
Production
Development
Testing
Management
Security
Shared ServicesThese environments may require different networks or routing domains.
Avoid overlapping address spaces whenever possible.
A structured plan might reserve:
10.10.0.0/16 Production
10.20.0.0/16 Development
10.30.0.0/16 Shared Services
10.40.0.0/16 ManagementCentralized architectures often route traffic through a dedicated security layer.
Spoke
|
Transit Hub
|
Firewall
|
DestinationPossible methods include:
A network architecture is incomplete until failure behavior is understood.
Engineers should know what happens when:
One of the most common mistakes is building the cloud network one application at a time without creating an overall IP addressing and routing strategy.
Another is assuming that because the cloud provider manages the physical network, customers no longer need networking expertise.
The opposite is often true.
Cloud networking combines traditional networking with software-defined infrastructure.
Engineers may need to understand:
TCP/IP
DNS
DHCP
BGP
CIDR
NAT
VPN
Routing
Firewalls
Load Balancing
Linux Networking
Cloud APIs
Infrastructure as CodeFor readers strengthening those fundamentals, our DNS Explained and DHCP Explained guides provide useful foundations before moving into more complex cloud routing designs.
There is no universal cloud network architecture that fits every organization.
AWS provides powerful VPC and Transit Gateway architectures.
Azure combines VNets with technologies such as Virtual WAN, ExpressRoute, and Microsoft’s global backbone.
Google Cloud combines its global VPC model with Network Connectivity Center, Cloud Router, Cloud VPN, and Cloud Interconnect.
The more useful question is therefore not simply:
Which cloud provider has the best network?
Instead ask:
Which architecture best matches the application’s routing, latency, availability, security, hybrid connectivity, operational, and cost requirements?
A small web application may need only a VPC and a few subnets.
A multinational enterprise might require:
Multiple Regions
|
Regional Transit Hubs
|
Global Backbone
|
Hybrid Connectivity
|
Enterprise WAN
|
Branch OfficesUnderstanding the difference between those architectures is what turns basic cloud deployment into professional cloud network engineering.
Cloud networking sits at the intersection of traditional networking, distributed systems, cybersecurity, and automation.
AWS, Azure, and Google Cloud abstract much of the physical infrastructure, but the fundamental networking principles remain remarkably familiar.
Packets still need routes.
Networks still need address plans.
Firewalls still need policies.
Distributed applications still depend on latency and availability.
And poorly designed routing can still break an otherwise perfectly configured application.
The major difference is scale.
Instead of designing a network for one building or data center, cloud engineers can design networks spanning continents, cloud regions, enterprise sites, and multiple providers.
That is why understanding cloud network architecture is becoming a core skill not only for cloud architects but also for network engineers, Linux administrators, DevOps engineers, and cybersecurity professionals.
As the next step, the CorgiNetwork Cloud & DevOps cluster will go deeper into the technologies behind this architecture—including AWS Transit Gateway, Azure Virtual WAN, Google Network Connectivity Center, BGP in cloud environments, hybrid cloud networking, multicloud routing, and Terraform-based network deployment.
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