Community Blog Simplify and Optimize Your Network with SD-WAN

Simplify and Optimize Your Network with SD-WAN

This article explains what SD-WAN is, its advantages, and compares it to traditional WAN.

By Rishu Mehra

What is SD-WAN?

Software-Defined Wide Area Network (SD-WAN) is an architecture that virtually empowers businesses and IT to leverage any mixed transport services to connect users to applications securely, such as LTE, internet broadband, and MPLS. This leads to a better performing network infrastructure with complete packaged application access so users can work hassle-free from anywhere and on any device.

SD-WAN adopts a central control function to route traffic across WANs securely and intelligently, leading to:

  • Greater performance in application
  • Excellent user experience
  • Impactful business productivity and agility
  • Better return on investments (ROI) for IT

In other words, an SD-WAN bridges a user to any business or technical application securely, even if it is hosted at an on-premises data center or in the cloud over any WAN service comprising of internet broadband services.

Differences Between Traditional WAN and SD-WAN

Traditional WAN was designed to route traffic and provide user access to the application from outside of the LAN. Over time, businesses grow and position at different physical locations that require a network solution to be rigid and support different users from different locations to securely access the application whether it is on a headquarters' data center or the cloud. SD-WAN solves this issue intelligently. The following table compares traditional WAN and SD-WAN:

Traditional WAN SD-WAN
Router-centric architecture Virtual WAN
Dependent on on-premise data centers Virtual WAN
Application performance was not predictable Assured enterprise-grade application performance with zero percent downtime
Limited bandwidth Consolidated and equipped bandwidth
Complex infrastructure Simplified branch services
Not optimized for the cloud and advanced services Optimized for the cloud and lets you work from any device

Traditional WAN used to cause a lot of delays in application performance results with bad user experience and reduced productivity. The SD-WAN architecture was designed to support applications hosted either in on-premise data centers or public/private clouds. SaaS services deliver the best performance of the application.

Benefits of SD-WAN

Traditional WAN architecture had limitations, typically confined within the company's network or branches with in-house data centers. As the companies start adopting cloud-based applications, such as SaaS or IaaS, the WAN architecture exploded with huge traffic to access the applications across the locations. With these changes, IT has multiple implications for:

  • The impact of employee productivity with performance problems in SaaS application performance problems
  • A spike in WAN expenses with inefficient usage
  • IT teams facing a complex way of working daily to connect different types of users with different types of devices to different cloud services

SD-WAN enables CIOs, system admins, and IT teams to do much more for the entire organization, including better routing, increased security, better private/public cloud performance, and most importantly the simplified management of WAN network. These reasons offer various benefits:

Awesome Experience

  • For all critical enterprise applications, it ensures high availability with predictable service
  • Routes the application traffic dynamically to ensure efficient delivery and better user experience


  • Integrated application-aware policies and segmentation with real-time access control
  • Reinforce threat protection at correct the place
  • Ensure secure traffic beyond broadband and the cloud
  • Better VPN implementation to access applications from public or private networks

Optimized for the Cloud

  • Flawless WAN expansion to multiple public clouds
  • Real-time optimized performance for major SaaS applications

Simplified Management

  • Management dashboard to configure and manage WANs, clouds, and security from a single console.
  • Usage of templates for zero-touch provisioning for different locations
  • Any time reports, analytics, application forecasts, and WAN performance for business and IT

Tips to Manage and Simplify SD-WAN Migration

Adding SD-WAN to your network or IT infrastructure can simplify your overall architecture and management, but sometimes adopting a new piece of technology is complex and involves cost investment.

To ensure the best application performance and network security with seamless migration, the following pointers will help you:

Assess the existing network and infrastructure properly

Thoroughly assess the network and IT infrastructure to examine which part is missing in the current WAN and which are most required to adopt SD-WAN. Thorough mapping will ensure a smooth transition or migration. This mapping and assessment include all of the recommended things for your infrastructures, such as IP modeling, DHCP, key applications, current hardware configurations, availability with public/private clouds, and many other things that system admins typically take care of in their routine. This helps the process become simpler during migration.

Evaluate the functions you want to remove

With SD-WAN, everything becomes centralized in the organization, and the cost is always involved to manage all of the resources remotely. To be more efficient while managing, keep fewer functions for quickness, and use complex algorithms for better security. Some applications and databases that are on-premise data centers with the cybersecurity of data may make your transition easier, but some still require licensing and have security concerns. There are always alternatives to such applications but your business requirements should fulfill them. While including public cloud applications, you should choose ones that easier to set up. It will save a lot of time and make your monitoring easier.

Create space for extra IP addresses for better network management

Network engineers should have a strategy to quickly determine the traffic origin and consider the space for new or extra IP addresses growing in the future. Examining the IP Addresses is one the most crucial parts to making SD-WAN a win-win adoption. Also, ensure no overlapping IP addresses exist within the organization or branch. This will also prevent conflicts of VPN use.

Server Configuration

Different businesses, different branches, and different units have a variety of infrastructure requirements over the network. Use a robust server configuration for your network server to monitor with pro-active tools to ensure zero percent downtime. Use the DHCP server for larger branches as needed for many IP addresses. Use the static IP address approach for smaller organizations. For DNS Servers, having a centralized server is always the best choice since either the DNS is public or private. Ensure that your SD-WAN service has an NTP server to understand the sequence of network events.

Now, the SD-WAN is a simple process that centralizes all of the network components with the cloud and is very efficient. Alibaba Cloud also provides key products to fulfill the SD-WAN requirements to ensure secure and private/public usage of service:

Virtual Private Cloud

VPC helps you build an isolated network environment based on Alibaba Cloud, including customizing the IP address range, network segment, route table, and gateway. In addition, you can connect the VPC and a traditional IDC through a leased line, VPN, or GRE to provide hybrid cloud services. Some of the benefits are listed below:

  • Secure Isolation: Builds an isolated network environment based on Alibaba Cloud. Layer-2 logical isolation is achieved between different VPC instances.
  • Flexibility: SDN configures the network as required and customizes the IP address range and route table.
  • Scalability: Works with multiple products and easily manages Internet portals to provide a hybrid cloud architecture.
  • Free of Charge: Achieve a fully isolated VPC environment for free on the Alibaba Cloud platform.

Alibaba Cloud DNS PrivateZone

You can use PrivateZone to quickly build a DNS in one or more specified VPCs and resolve private domain names to IP addresses. Some of the benefits are listed below:

  • Secure: Private domains can only be accessed in associated VPCs based on Alibaba Cloud's unique VPC tunnel IDs.
  • Immediate Response: You can use PrivateZone to change configurations quickly because the VPC-based DNS resolver returns the IP address immediately with no need for recursive DNS queries.
  • Flexible: You can add existing domain names and subdomain names on the Internet and custom domain names to PrivateZone.
  • Reverse Lookup: PrivateZone supports reverse lookup that resolves IP addresses to domain names.
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