Multicloud Networking Services: Interconnecting Multiple Cloud Environments
Multicloud networking services address the architectural challenge of linking workloads, data, and applications distributed across two or more public cloud providers — such as AWS, Microsoft Azure, and Google Cloud — along with private cloud or on-premises infrastructure. This page covers the definition, functional mechanics, deployment patterns, and selection criteria for multicloud networking approaches. Organizations that operate across heterogeneous cloud environments face distinct routing, security, and performance problems that single-cloud networking models do not encounter, making purpose-built interconnection strategies a operational necessity rather than an optional enhancement.
Definition and scope
Multicloud networking is the practice of establishing controlled, policy-governed connectivity between discrete cloud provider environments so that applications and services can communicate as if operating within a unified network fabric. The scope extends beyond basic internet-routed cloud access to include dedicated inter-cloud links, overlay networks, unified traffic policy enforcement, and centralized visibility across all cloud domains.
The National Institute of Standards and Technology (NIST) defines cloud computing in NIST SP 800-145 as a model enabling ubiquitous, on-demand access to a shared pool of configurable computing resources. Multicloud networking operates at the intersection of at least 2 distinct cloud deployment models — typically combining public cloud infrastructure from separate providers — and must reconcile divergent native networking constructs (VPCs on AWS, VNets on Azure, VPCs on Google Cloud) into a coherent interconnection architecture.
Scope boundaries matter when distinguishing multicloud networking from adjacent concepts. A hybrid cloud networking arrangement connects public cloud to a private cloud or on-premises data center, while multicloud specifically denotes multiple public cloud providers in use simultaneously. SD-WAN services can serve as an underlay transport mechanism for multicloud environments but do not themselves constitute multicloud networking — they are one layer of a broader stack.
How it works
Multicloud networking relies on 4 primary technical layers working in combination:
- Physical or logical transport — Dedicated interconnect services (such as AWS Direct Connect, Azure ExpressRoute, or Google Cloud Interconnect) provide private circuits between provider edge nodes and enterprise facilities or colocation sites. These bypass the public internet to reduce latency variance and improve throughput predictability.
- Overlay network fabric — Software-defined overlay networks use encapsulation protocols (VXLAN, GRE, or IPsec tunnels) to extend logical network segments across cloud boundaries without depending on each provider's native peering. Cloud-native virtual routing appliances or third-party virtual network functions deployed in each cloud instance terminate and forward these tunnels.
- Centralized control plane — A unified controller or management platform maintains routing tables, enforces segmentation policies, and propagates configuration changes across all cloud environments. This layer is analogous in function to the control plane described in network virtualization services, applied at inter-cloud scale.
- Unified observability — Flow telemetry, latency metrics, and security event logs from each cloud domain are aggregated into a single monitoring plane. Without this layer, operators cannot correlate performance degradation or security incidents that span provider boundaries.
The Internet Engineering Task Force (IETF) has published foundational documents governing the encapsulation and routing protocols underpinning most overlay implementations, including RFC 7348 for VXLAN and RFC 4271 for BGP, which is the primary routing protocol used to exchange reachability information between cloud edge routers.
Common scenarios
Multicloud networking services appear across 3 recurring deployment patterns:
Workload distribution across providers for regulatory or resilience reasons — Regulated industries, including healthcare and financial services, sometimes place specific data sets in a geographically constrained cloud region of one provider while running processing workloads in a second provider's region. Network compliance and regulatory requirements vary by sector, and multicloud routing enables data residency constraints to be enforced at the network layer rather than solely at the application layer.
Active-active redundancy across cloud providers — Organizations that require sub-minute recovery time objectives distribute identical application stacks across 2 cloud providers and use multicloud networking to synchronize state and route traffic in real time. This contrasts with a single-cloud active-passive configuration, where failover depends on within-provider recovery mechanisms. Network redundancy and failover services provides a direct comparison of these architectural options.
Mergers, acquisitions, and multi-tenant SaaS architectures — When two organizations merge and each operates a different primary cloud provider, multicloud networking provides the bridging layer during and after integration. SaaS providers serving enterprise clients frequently must interconnect their cloud environment with client-specific cloud tenancies, a scenario requiring dynamic, policy-scoped connectivity rather than static VPN tunnels.
Decision boundaries
Selecting a multicloud networking approach involves evaluating 4 structural trade-offs:
- Managed vs. self-operated fabric — Managed network services abstractions for multicloud are offered by network service providers who operate the overlay fabric on the customer's behalf, reducing operational burden but introducing a third-party dependency in the data path.
- Native cloud interconnect vs. third-party overlay — Native interconnect services from each cloud provider offer the lowest-latency path but require separate management consoles per provider and do not support unified policy. Third-party overlay networks provide a single control plane but add an encapsulation overhead of typically 50–150 bytes per packet depending on the protocol.
- Centralized vs. distributed control — Centralized control planes simplify policy management but create a single operational dependency. Distributed control, where each cloud region runs autonomous routing, improves resilience but complicates consistent policy enforcement.
- Cost model alignment — Egress fees charged by cloud providers are a primary cost driver in multicloud networking. AWS, Azure, and Google Cloud each publish pricing schedules through their official documentation; traffic engineering decisions in the routing layer directly affect which provider's egress meters accumulate charges, making network services pricing models analysis a prerequisite to architecture finalization.
Organizations with stringent security posture requirements should evaluate multicloud networking in conjunction with zero-trust network services, since inter-cloud traffic traversing overlay fabrics requires explicit identity and policy verification at each domain boundary rather than relying on network perimeter assumptions inherited from single-cloud models.
References
- NIST SP 800-145: The NIST Definition of Cloud Computing — National Institute of Standards and Technology
- IETF RFC 7348: Virtual eXtensible Local Area Network (VXLAN) — Internet Engineering Task Force
- IETF RFC 4271: A Border Gateway Protocol 4 (BGP-4) — Internet Engineering Task Force
- NIST SP 800-53 Rev 5: Security and Privacy Controls for Information Systems and Organizations — National Institute of Standards and Technology
- IETF Datatracker — Network Virtualization Overlays (NVO3) Working Group — Internet Engineering Task Force
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- Types of Networking Services: A Complete Reference
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