What is Network Overlay in SDWAN? Detail Guide

What is Network Overlay in SDWAN?

Network overlay in SDWAN is a technology that uses software-defined networking (SDN) to create virtualized network connections between different sites, allowing for optimized performance and secure access. It creates virtual networks or “overlays” on top of existing physical networks, which can be used for Internet traffic management, segmentation of public and private traffic, and increased scalability.

How Does Overlay Network Work in SDWAN?

The working of an overlay network starts with a virtualized networking layer created on top of the existing physical networks. This layer is referred to as a “tunnel,” and it allows traffic to be securely routed between two points without having to traverse the public internet. The tunnel can also be used for the segmentation and segmenting of different types of traffic, allowing for increased security and flexibility.

When a packet is sent through the tunnel, its traffic is encapsulated and routed securely to its destination without having to traverse any public networks. This eliminates latency, ensuring reliable performance.

What are the Advantages of Overlay Network?

Here are some of the advantages of using an overlay network in SDWAN:

  • Increased security: Network overlays can provide enhanced security measures, such as encryption and authentication, which allow businesses to keep their data safe from malicious actors.
  • Improved scalability: With SDWAN’s virtualized architecture, networks can be easily scaled up or down depending on the needs of the business.
  • Enhanced performance: By routing traffic through virtualized tunnels, performance can be improved significantly compared to using public networks.
  • Cost savings: Overlay networks allow businesses to take advantage of existing infrastructure without having to purchase additional equipment, which leads to lower costs.

How We Can Improve the Security with Help of an Overlay Network?

Here are some of the ways an overlay network can help improve security in SDWAN:

  • Encryption: Network overlays can offer end-to-end encryption, which ensures that data is kept secure in transit.
  • Authentication: Authenticating users and devices help prevent unauthorized access to networks, allowing businesses to control who has access to their data.
  • Segmentation: By segmenting traffic, businesses can ensure that only the necessary traffic is allowed to traverse through their network.
  • Monitoring and logging: Network overlays can be used to monitor and log activity on the network, allowing for better visibility into what’s happening on the network and helping organizations identify potential threats.

How We Can Enhance the Performance with Help of an Overlay Network?

Here are some of the ways an overlay network can help improve performance in SDWAN:

  • Optimized routing: Network overlays allow for traffic to be routed more efficiently, reducing latency and improving overall network performance.
  • Load balancing: By using virtualized networks, businesses can effectively balance the load on their networks, ensuring that resources are allocated more efficiently.
  • QoS: Network overlays can be used to prioritize certain types of traffic, ensuring that critical applications receive the necessary bandwidth and performance they need.
  • Fault tolerance: By using virtualized networks, network failures can be quickly detected and avoided, resulting in improved availability and reliability.
  • Capacity management: With virtualized networks, businesses can quickly and easily scale up or down depending on their needs.

What are the Disadvantages of Overlay Networks?

Here are some of the drawbacks of using an overlay network in SDWAN:

  • Increased complexity: Since it involves multiple layers and complex routing protocols, setting up and managing an overlay network can be complicated.
  • Higher latency: While traffic routed through overlays is generally more secure than traditional public networks, it can lead to higher latency due to the additional overhead required to establish the tunnels.
  • Lower resilience: Overlay networks are more prone to failure than traditional networks due to the complexity of the setup and routing protocols. If one link fails, the entire network can be affected.

What are the Use Cases of Overlay Networks?

There are a number of use cases for overlay networks in SDWAN, including the following:

  • Cloud migration: Network overlays can be used to facilitate migrating applications and data to the cloud, allowing businesses to benefit from the scalability and flexibility of cloud computing.
  • Hybrid WAN: Overlay networks can be used to connect multiple locations, allowing businesses to take advantage of different networks and technologies.
  • Content delivery: By utilizing content delivery networks (CDNs), businesses can ensure that their applications are delivered quickly and reliably to remote users.
  • Service mesh: Service mesh architectures allow for easier management of microservices, making it simpler to deploy complex distributed applications.
  • Network segmentation: By segmenting networks, businesses can ensure that only the necessary traffic traverses through their network. This can help improve security and performance while also reducing costs.
  • Edge computing: Network overlays can be used to enable edge computing, allowing businesses to deploy applications closer to users for faster response times.

Explanation of Overlay Network in Cloud Migration with Example

Consider a company with multiple on-premise servers and databases that need to be migrated to the cloud. The company could use an overlay network, such as a virtual private network (VPN), to create a secure tunnel between the on-premise servers and the cloud. This ensures that all traffic passing between the two sites is encrypted, thus providing an additional layer of security for the data being migrated.

Once the initial connection has been established, data can be transferred more quickly and securely than it would with traditional methods.

Explanation of Overlay Network in Hybrid WAN with Example

Consider a company that operates multiple locations and needs to connect them all together. The company could use an overlay network, such as a virtual private LAN service (VPLS), to link all the sites. This would provide a secure connection between the different offices, allowing for data transfer and communication without having to rely on public networks or dedicated leased lines.

Using an overlay network would also allow the company to take advantage of different networks and technologies, as they could choose whichever type of connection works best for their needs. For example, they could use wired connections in some locations and wireless connections in others to create a hybrid WAN.

Explanation of Overlay Network in Content Delivery with Example

Consider a media company that needs to deliver its content to users across the globe. The company could use an overlay network, such as a content delivery network (CDN), to ensure that its content is delivered quickly and reliably.

A CDN uses multiple servers in different locations to store and serve the content. When a user requests the content, the CDN will determine which server is closest to them and serve the content from that location. This helps reduce latency and ensures that users get the best experience possible.

What Technologies Supports Overlay Networks?

There are a number of technologies that can be used to support overlay networks, including the following:

  • Virtualization: Virtualization technologies such as hypervisors allow for the creation and deployment of virtualized networks.
  • SDN controllers: Software-defined networking (SDN) controllers provide visibility and central control over an entire SDWAN, making it easier to deploy and manage overlay networks.
  • Network virtualization: Network virtualization technologies such as OpenFlow and Virtual Extensible LAN (VXLAN) allow for the creation of private layer-2 networks over public infrastructure, making it possible to set up distributed overlay networks.
  • Routing protocols: Routing protocols such as Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP) are used to route traffic between overlay networks.
  • Encryption technologies: Encryption and authentication technologies such as IPSec and Transport Layer Security (TLS) can be used to secure communications across an overlay network.

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