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The Difference Between WAN And SD-WAN |

Traditional WAN And SD-WAN are both network technologies. However, the primary difference between WAN vs SD-WAN is how they are used. If are you looking for a reliable internet connection due to frequent issues in your existing network infrastructure or considering a cloud migration strategy? Then, it might be a perfect time to consider the benefits of software-defined WAN or SD-WAN. It is becoming popular among businesses throughout the world.

The reason behind it is that it is delivered through the cloud, and businesses can reduce their capital expenditures and simplify their network operations by using it. On the other hand, traditional WAN usually incorporates a hybrid of a public and leased line. Like all other things, all WANs are not equal, so you have to choose the right one that meets the needs of your business.

The main difference between WAN and SD-WAN is the technology they use to operate and how it affects your business in terms of cost, performance, redundancy, security and more. To help you out, we are providing a comparison of traditional WAN and SD-WAN in this article.

SD-WAN Explained

SD-WAN is a Software-Defined Wide Area Network that is a virtual WAN architecture. It allows businesses or organisations to leverage any combination of transport services such as broadband internet service, MPLS and LTE to connect users to applications in a secure way.

It intelligently directs traffic to the WAN by using a centralized route. Thus it increases application performance and provides a high-quality user experience, ultimately resulting in business productivity and agility. Moreover, it helps companies to reduce the cost of IT.

We can say that SD-WAN is a network operating on the top of other networks in which communication paths are unified, and application performance is optimized. Moreover, as it is a cloud-based network, it is easy to deploy it as compared to traditional WAN.

How Does SD-WAN Work?

SD-WANs are created by establishing encrypted tunnels between different sites. Every site has an SD-WAN device. Once these devices are connected with a local network, they automatically download traffic policies and custom-defined configurations and connect tunnels with each other or to the point of presence based on the architecture.

The purpose of SD-WAN is to control and route traffic. It routes outbound traffic along an optimum path depending on real-time traffic conditions and application policies. If one last-mile connection fails, the SD-WAN device finds an alternative connection automatically through pre-configured policies and manages the traffic load in an efficient way.

Policy-based management is the key component on which an SD-WAN works. This policy is established to determine dynamic paths for traffic and SD-WAN route traffic based on the priority of your business, for example, the quality of service it has given. You can make more than one policy to meet your business requirements, such as granting priority to packet transmission for VoIP and other interactive services to make your business perform better.

Benefits Of SD-WAN

There is multiple benefits of SD-WAN which we discuss below. SD-WAN is only a change in the way a wide area network is deployed and managed. As the name suggests, it is a software-driven technology deployed as an overlay technology that allows easy adoption and integration over time.

Following are some benefits of SD-WAN technology

  • Cost-Effective
  • Cloud-Based Services
  • Simplified Quality Of Service
  • High Bandwidth Support
  • Improve Traffic Management

1. Cost Effective

SD-WAN technology helps businesses to eliminate the cost of MPLS circuits. Instead, it makes use of high speed and low-cost connectivity options such as a DSL or broadband. However, the MPLS circuits can still be used depending on circuit availability, ease of integration and additional SLA requirements.

2. Cloud-Based Services

In a traditional WAN architecture, the traffic usually returns to the centres due to the need for constant filtering. It results in potential latency and sub-optimal latency for cloud-hosted providers. SD-WAN moved us towards a local internet offloading and getting user traffic closer to cloud services.

3. Simplified Quality Of Service

Another important benefit of SD-WAN is that it provides simplified quality of service (QoS) and prioritisation of important applications across the WAN. Instead of waiting for an up/down event , SD-WAN offers real-time monitoring of traffic so that it can divert business-critical traffic in brownout events.

4. High Bandwidth Support

SD-WAN has the ability to support high bandwidth applications and simultaneously offload them on the local internet where applicable. In contrast, these bandwidth requirements can be a challenge for traditional WAN.

5. Improve Traffic Management

The SD-WAN technology offers unified dashboards that give network performance metrics to the system administrators. It helps businesses in improving traffic management.

Disadvantages Of SD-WAN

Like all other networks, SD-WANs have some flaws along with benefits. Following are some of the drawbacks of SD-WAN that you should consider:


Businesses are still relying on conventional connections and have not fully adopted SD-WANs for their internal and external operations. However, they compensate for this by adopting hybrid connections.

    • Security standards of SD-WANs are a bit low as there is no on-site security functionality. There is a need to implement security standards to make sure your network is protected from external threats. It is because only a single data breach can cause a huge impact on an entire enterprise.


    • If you are using only SD-WAN provisions, there is no end to end quality of services (QoS).


    • Your IT staff may need to make much effort to deploy and maintain this technical network. Furthermore, if they are unable to deploy it, you need to call outside help that can be expensive.


  • The SD-WAN vendors tend to vary, and sometimes they can not meet what is actually envisioned for software-based networking.

What is WAN?

A traditional WAN has been present in the market for several years. This technology has long been the go-to for data network infrastructure, voice and IT. For example, if you have multiple office locations, you can use traditional WAN to connect these locations.

A WAN connects local area networks (LANs) with each other by using a virtual private network (VPN) or through routers. Traditional WAN typically depends on dedicated protocol label switching (MPLS) to provide your business with a direct and secure connection to manage traffic flow reliably and efficiently. It also enables you to priorities video, voice or data traffic on your network.

How Does Traditional WAN Work?

Traditional WANs need the purchase and installation of proprietary circuits in order to route IP services to their potential clients. Layers of the underlying hardware are required to make this network functional. The IT teams find it cumbersome to manage such networks.

Furthermore, it requires a laborious effort to install a number of hardware devices and to manage the network activity. In traditional WAN, network security is handled in the form of access control lists and IP block lists to protect your network from infiltration of malicious traffic. You may also need additional hardware to set up additional branch offices that ultimately increase your capital expenditure.

In addition, the scaling of conventional WAN is challenging compared to the SD-WAN. It is because you would need to do advance planning as well as require logistical support to set up new infrastructure and make it operational.

Disadvantages Of Traditional WAN

Depending on your business requirements, a traditional WAN can be an obstacle to the growth and agility of your business. Therefore, you must consider the following disadvantages of as a forward-thinking IT leader:

    • If a failover occurs and you need to switch to a standby server or a system when your main application goes down, it entirely depends on the state of the link. The Failover can result in an outage of multiple seconds that can cause a drop in phone or video calls. 


    • You need to manage each device as per new policies, and your administrator requires you to touch each individual device with the change of policies.


    • Another disadvantage of conventional WAN is that it has distributed configuration, which means that configuration is routed locally on each router.


  • A significant amount is required for a new site to turn up. It includes time for equipment provisioning, circuit delivery and change management. Change management and project coordination are complex processes that are why it can take up to a month for new sites to turn up.

Traditional WAN Vs SD-WAN

To understand the difference between traditional WAN and SD-WAN and to choose which one is better for your business, it is necessary to compare the features of these two network technologies.

1. Reliability And Prioritization

Traditional WANs run over MPLS and offer a high quality of service (QoS) because they avoid packet loss by virtually isolating packets. Usually, it runs over a carrier-grade circuit connection. However, you must keep in mind that a traditional WAN using MPLS bandwidth like this can be a costly option for your business.

It is crucial to determine which traffic will get the higher priority, and it can help organizations to ensure their calls are not dropped. Traditional WAN allows you to priorities traffic and can also give you traffic reliability and predictability. 

On the other hand, when it comes to SD-WAN, you can see that your net cost can be reduced by using SD-WAN as you do not need to pay much to upgrade your bandwidth as well as it enables you to mix and match network links in a budget-friendly way, according to your content type and priority. An SD-WAN can run on LTE, 4G and internet broadband which is relatively less expensive than a service that uses MPLS networks.

SD-WAN not only offers you dozens of application prioritization options but also allows you to send your most essential data traffic over the best network link. It results in only a little or no latency and packet loss. Furthermore, if there is an outage, the SD-WAN switches your traffic to another connection immediately.

2. Scalability And Control

If You Want To to upgrade or make changes to your traditional WAN, it needs to be done manually. It can be a laborious process and takes more time, leading to a decrease in the efficiency of your business. This scaling or up-gradation highly affects the performance of growing businesses. 

On the other hand, SD-WAN is a software-based solution, and you can scale SD-WAN in a relatively easy and simple way. When your organisation grows, you need to upgrade your connectivity networks, and with SD-WAN, you can do it without any hassle, especially if you partner with a managed and well-reputed provider.

3. Security

When it comes to security, both traditional and SD WANs offer security on their own terms. When we look at security, we can see that traditional WAN is considered secure. This is because the packets that it sent over the MPLS connection are private, and only destined MPLS connections can see them. It means it allows only site-to-site communication.  

SD-WAN keeps your traffic secure through end to end encryption over a VPN (a virtual private network). The benefit of using this technology is that you can easily integrate and implement additional security layers such as firewalls for unified threat management.

Why Should You Choose SD-WAN?

The time has changed, and enterprises are now using advanced technologies such as cloud-based applications and are subscribing to software-as-a-service. And the users conventionally connected back to the data centers for business applications are now accessing the same applications in the cloud.

That is why traditional WAN is not suitable to meet the connectivity requirements of businesses. Furthermore, this traditional approach causes backhauling of traffic and latency in connecting from headquarters to branch offices and impacts applications performance.

On the other hand, SD-WAN helps you in sending the most important data through the best-wired connection and brings new agility to the WAN. It offers WAN simplification, reduces costs, bandwidth efficiency and improves the performance of cloud-based applications. Furthermore, it does not impact the data privacy and security of your business.

Final Words

Now that you know the positive and negative sides of traditional WAN and SD-WAN. You can make a better decision to choose one of them according to your business requirements. However, with the advancement in technologies, we suggest you choose SD-WAN so that you can improve the efficiency of your cloud-based applications and receive a high bandwidth at a lower cost.

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