Network Overlay and Connectivity in the Multi-cloud space

  • Ravi Jha
  • Jun 13, 2019
  • 3 min read
Network Overlay and Connectivity in the Multi-cloud space

Synopsis: With multi-cloud architectures ruling the enterprise IT space, networking needs to evolve too. Here’s how network overlay can prove to be a game changer by providing agility required for multi-cloud environments. 

Although not a recent concept, network overlays have been garnering a lot of attention since last few years with virtualization and cloud computing coming into the picture. This is because overlay networking plays a great role in helping organizations realize the key benefits of these technologies—speed, flexibility and reduced cost. Now, as multi-cloud environment continues to become the new normal in enterprises, discussions around overlay network are gaining further steam. 

Essentially, overlay networking is all about creating layers of network abstraction using software. This enables running multiple virtualized networks on a common physical network, wherein disparate virtual networks run as independent networks on top of the physical network. Multiple virtual network topologies overlaid on a single physical infrastructure can be achieved with virtual network being a Layer 2 or Layer 3 network, while the physical network can be Layer 2, Layer 3 or a combination depending on the overlay technology. 

In the context of multi-cloud, overlays can prove to be a game changer in ?connecting cloud environments across the service providers together. Network overlay also addresses the issue of security and isolation associated with the multiple cloud environment. With overlays, network services become like applications which can be rapidly developed, deployed and modified to serve customers anywhere. 

Here’s how overlay network-based approach enables enterprises to maximize the business value of the multi-cloud environment: 

Flexibility: When deploying or updating services and apps in multi-cloud, network administrators need to configure the network. With network overlays, virtualization takes place at the network edge, whereas the remainder of the L2/L3 network remains unchanged. This removes the dependence on underlying infrastructure configuration. Endpoints are assigned to a virtual network via a Virtual Network ID, corresponding to that virtual network irrespective of their location on the underlying physical IP network. Thus, the virtual networks in multi-cloud architecture operate, as long as IP connectivity is available without the need for any configuration change. Further, network overlays typically provide a 24-bit virtual network interface (VNI) that supports as many as 16 million virtual networks as compared to support provided for only 4,096 isolated networks with VLANs. 

Cohesive deployment: Both physical servers and appliances (firewalls, load balancers, etc.,) can be added to the overlay with a physical switch that acts as a tunnel endpoint. This lays the foundation of consistent deployment in a mixed workload environment typical to multi-cloud environments. 

Configuration: Integration and unified management of multiple clouds and data, applications and containers running on them is far more complex than managing a single cloud. In this context, overlay networks greatly simplify the configuration and weave together the multi-cloud environment. As virtual network in overlay networking rides on top of the underlying IP networks, it looks the same to the application despite the difference in underlying network technology. 

Accelerate Migration: In a multi-cloud environment, migration is a complex process as it can be across different cloud platforms or infrastructure (public, private, virtual private). As network overlays eliminate network configurations constraints, they accelerate continuous deployment of dynamic applications. Overlay-based networking approach securely serves data communication needs of any application, enabling efficient migration across any cloud. 

As more and more enterprises continue to adopt multi-cloud to access benefits, such as greater agility, improved time to market, and reduced costs, network overlays will emerge as de-facto standard to fulfil on multi-cloud’s promise. Choosing a service provider that takes a vendor agnostic approach for multi-cloud environment and has significant experience to provide support for multiple overlay technologies and SDN controllers, can help enterprises ensure greater network robustness.



Ravi Jha

Ravi Jha

Associate Vice President and Head - Products, NTT Global Data Centers and Cloud Infrastructure, India

With over 18 years of industry experience, Ravi is the Associate Vice President and Heading Products at NTT Global Data Centers and Cloud Infrastructure, India. Ravi has been instrumental in spearheading and launching various Network Products such as SDWAN, Global IPVPN, Domestic MPLS, DC Connect and DIA services in the Indian Market.

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