Data Center Fabric

Deploy a massively scalable, automated, and resilient data center fabric with the open, disaggregated power of OcNOS. Engineer your network for the demands of cloud, virtualization, and AI.

Discover Key Advantages in OcNOS Hybrid Cloud-Native DC Whitepaper

Modern DC Clos

A modern DC CLOS fabric, also known as a spine-leaf architecture, is the industry-standard blueprint for building a high-performance data center. It provides a faster, more resilient, and scalable foundation specifically engineered to handle the intense east-west traffic from today’s AI and cloud workloads.
Diagram showing the shift from North-South to dominant East-West traffic patterns in modern data centers.

Maximize Throughput and Performance

The non-blocking nature of the CLOS fabric ensures your network capacity is fully utilized, preventing traffic hotspots and allowing data to flow freely.

Predictable Low-Latency

With a fixed, two-hop path between any servers in the fabric, you get the consistent, ultra-low latency required to accelerate AI/ML and demanding workloads.

Scale Seamlessly and Cost-Effectively

The modular design lets you add capacity on demand simply by adding more switches, enabling a pay-as-you-grow model that avoids disruptive and expensive “rip-and-replace” upgrades.

What is a Non-Blocking Architecture?

A non-blocking architecture for the DC CLOS prevents internal congestion by ensuring the total uplink bandwidth from leaf switches to spine switches matches the aggregate bandwidth of all connected server ports. This 1:1 oversubscription ratio allows every server to transmit at line rate without creating bottlenecks, providing a predictable and high-performance network.

EVPN-VXLAN for DC CLOS

Your high-performance CLOS is the physical superhighway for your data, but your business services need to be deployed and scaled instantly, without being tied to specific racks or rows. EVPN-VXLAN creates secure, virtual “tunnels” over your physical network, giving you the freedom to run any service, anywhere, at any scale.

Deploy Workloads Anywhere, Instantly

Create a seamless Layer 2 network that stretches across your entire Layer 3 fabric. Place or move a virtual machine or container anywhere you have capacity.

Isolate Every Tenant and Application

Move far beyond the 4,000 VLAN limit and create up to 16 million logical networks. Build secure, completely isolated virtual networks running on the same shared physical infrastructure.

Maximize Uptime and Bandwidth

EVPN multihoming allows a server to connect to two switches in a resilient, active-active mode. Both links are always forwarding traffic – doubling available bandwidth

 

Learn More in OcNOS Hybrid Cloud-Native DC Whitepaper

Understanding the VXLAN EVPN Topology

This diagram provides a detailed visual of a modern Data Center Clos Fabric using EVPN-VXLAN. It illustrates the critical relationship between the physical network (the underlay) and the virtualized network (the overlay) and shows how key components work together to provide agility, security, and high availability for modern cloud and enterprise environments.

 

VXLAN EVPN Architecture Diagram showing Underlay and Overlay networks

VXLAN Tunnel Endpoint (VTEP)
The VTEP is a network device, such as a switch or router, that originates and terminates VXLAN tunnels. Its primary function is to encapsulate Layer 2 frames from a tenant’s virtual network into Layer 3 UDP packets for transport over the physical underlay, and to decapsulate them upon arrival.

Network Virtualization Edge (NVE)
The NVE is the logical entity or interface on a VTEP that provides Layer 2 and Layer 3 network virtualization services. It maintains the mappings between tenant VNIs and the underlying VXLAN tunnels, effectively serving as the bridge between the virtual overlay and the physical underlay.

Virtual Network Identifier (VNI)
The VNI is a 24-bit field in the VXLAN header that provides segmentation for up to 16 million unique virtual networks, overcoming the 4,094-VLAN limitation. An L2 VNI defines a specific Layer 2 broadcast domain, while an L3 VNI is associated with a VRF for inter-subnet routing.

Overlay Network
The Overlay is the logical network of virtual tunnels created by VXLAN on top of the physical underlay. It is where tenant traffic is carried, completely decoupled from the physical network’s topology. This abstraction allows for the rapid deployment of isolated L2 and L3 services anywhere in the data center.

Underlay Network
The Underlay is the physical IP network responsible for providing robust, high-speed connectivity between all VTEPs. Its sole purpose is IP reachability, typically established using a scalable routing protocol like OSPF, IS-IS, or BGP, forming a stable foundation for the virtual overlay.

EVPN Control Plane
EVPN (Ethernet VPN) serves as the advanced control plane for VXLAN, utilizing Multi-Protocol BGP (MP-BGP) to exchange network reachability information. Instead of relying on data-plane flooding, EVPN advertises MAC addresses, IP addresses (MAC-IP bindings), and VNI information as BGP routes, enabling scalable and intelligent forwarding decisions.

Integrated Routing & Bridging (IRB)
IRB, also known as a distributed anycast gateway, is the mechanism for routing traffic between different VXLAN segments (VNIs). Each VTEP acts as a default gateway for its local hosts, allowing for optimal East-West traffic forwarding by routing at the ingress VTEP closest to the source.

Multi-Tenancy (VRF)
A VRF (Virtual Routing and Forwarding) instance creates an isolated virtual routing table, enabling Layer 3 multi-tenancy. In an EVPN fabric, each tenant’s L3 VNI is mapped to a unique IP VRF, ensuring complete traffic separation between different tenants on a shared physical infrastructure.

EVPN Multi-Homing
A key resiliency feature of EVPN, Multi-Homing allows a server to connect to two or more VTEPs in an active-active, load-balanced fashion. The EVPN control plane manages link and node failure detection, enabling sub-second failover and eliminating the need for inefficient protocols like Spanning Tree (STP).

Example Traffic Flow: Server A to Server D
Let’s trace a packet from Server A (192.168.10.10) to Server D (192.168.10.12).

Initiation: Server A sends a standard Ethernet frame destined for Server D.

Ingress & Encapsulation: Leaf Switch 1 receives the frame on VLAN 10. It knows VLAN 10 is mapped to Tenant A’s VNI 1000. Through the EVPN control plane, it has already learned that Server D’s MAC address is located behind the VTEP on Leaf Switch 3.

Tunneling: Leaf Switch 1 (the source VTEP) encapsulates the original Ethernet frame into a VXLAN packet, adding a header with VNI 1000. This VXLAN packet is then placed inside a standard IP/UDP packet. The source IP is Leaf 1’s VTEP IP, and the destination IP is Leaf 3’s VTEP IP.

Underlay Transport: The encapsulated packet is forwarded through the physical underlay network (e.g., from Leaf 1 to Spine 1 to Leaf 3). The underlay switches only care about the outer IP addresses (the VTEP IPs); they are completely unaware of the virtual network traffic inside.

De-encapsulation & Egress: Leaf Switch 3 (the destination VTEP) receives the packet. It strips off the outer IP/UDP and VXLAN headers, retrieves the original Ethernet frame, and forwards it to Server D via its connected port.

Powering Critical Workloads with OcNOS

An OcNOS-powered fabric is engineered to solve your biggest challenges. From accelerating AI to transforming your network economics, our solution provides the performance and freedom your business demands.

Accelerate Your AI Initiatives

OcNOS enables a lossless fabric tuned for the most intense workloads with support for RoCEv2 over a DCB-enabled network (PFC/ECN).

Deliver Scalable Cloud Services

With EVPN-VXLAN, you can automate service delivery and provide the stable, multi-tenant environment needed to grow your cloud business.

Unlock Strategic & Financial Agility

Our disaggregated model separates network software from hardware, giving you the freedom to choose best-of-breed whitebox switches. drastically reducing TCO.

Simplify and Automate Operations

Drastically reduce operational overhead and accelerate deployments with model-driven automation: OpenConfig, NETCONF/YANG, and gNMI.

 
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Resources & Technical Documentation

Explore our technical documentation, customer stories, and solution guides to see how the OcNOS Data Center Fabric can transform your network.

Solution Briefs & White Papers

White Paper: Migrating to Hybrid Cloud-Native Data Center

Learn the strategies and benefits of migrating to a modern, cloud-native architecture with an open networking foundation.

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Solution Brief: OcNOS for AI Fabric

Discover the technical advantages of building a high-performance, lossless fabric for demanding AI/ML workloads with OcNOS.

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Solution Brief: Data Center Interconnect

Learn how to build scalable, high-performance connectivity between your data center locations with OcNOS DCI.

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Product & Technical Documentation

Product Page: OcNOS DC

Get an overview of our flagship Network Operating System for data center and cloud environments.

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OcNOS DC Feature Matrix

Explore the comprehensive list of protocols and features supported by the OcNOS Data Center platform.

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Hardware Compatibility List

Browse the extensive ecosystem of open, whitebox hardware platforms compatible with OcNOS.

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Customer Stories & Videos

Customer Story: Scott Data

See how Scott Data, a Tier III Certified data center, deployed network disaggregation with IP Infusion OcNOS.

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Customer Story: Madeo

See how Madeo achieved greater flexibility and lower TCO by transitioning to an open data center network with OcNOS.

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Press Release: OcNOS AI Fabric with HYPERSCALERS

Learn how HYPERSCALERS built high-performance GPU-based services using OcNOS for their AI/ML workloads.

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OcNOS Video Tutorial

Watch our technical experts walk through key configurations and use cases for the OcNOS platform.

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Get Started Today!

Speak with an IP Infusion expert to discuss your specific needs and learn how we can help you unlock the full potential of your network with open networking solutions.

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