Are you facing issues with your current network infrastructure? Do you have a cloud migration strategy? If you haven’t considered the benefits of a software-defined WAN solution (SD-WAN), now might be the time. Why? Because it’s delivered through the cloud, SD-WAN reduces capital expenditures and simplifies network operations.

Businesses all over the world are adopting software-defined wide area networks (SD-WAN). The International Data Corporation predicts the SD-WAN market to reach $8 billion in the next five years.

So what makes SD-WAN better than traditional WAN? Let’s compare

How does traditional WAN work?

Traditional WAN has for long been a go-to for data networking, voice, and IT infrastructure. It is also used for linking organizations that have offices across various cities. Traditional WAN solutions use a hybrid of leased and public lines along with Virtual Private Networks or MPLS(Multiprotocol label switching) routers for added security. MPLS provides an efficient and resilient traffic flow. This allows data traffic prioritization, video, and VoIP(voice over IP) services.

Limitations of traditional WAN

Cumbersome installation and management

Traditional WANs require you to purchase and install proprietary circuits for routing IP services to the clients. This is usually done with layers of hardware. These networks make it difficult for the IT team to manage the process as it is quite laborious and cumbersome.

Expensive security infrastructure

The security in a WAN network is handled in the form of access control lists and IP blocklists for preventing malicious traffic from infiltrating the network. This is managed centrally with hardware routers. Setting up any branch office in remote locations will require additional hardware. This, in turn, will shoot up the costs required to do business.

Difficult to scale

Scaling traditional WANs is quite difficult. It demands extensive planning to set up the necessary infrastructure.

Traditional WAN may work well for some businesses but can prove to be quite expensive and inflexible for many. Disadvantages of traditional WAN are summarized below:

Difficult to scale

  • Expensive bandwidth and data center dependence.
  • Complex infrastructure and maintenance issues.
  • Unpredictable application performance.
  • High setup costs.
  • Routing can result in an outage for a brief period.
  • The configuration is housed locally on individual routers.
  • New policies have to be managed on per device basis, and each individual device has to be reconfigured for policy changes
  • A significant amount of time is required for new site deployment.

How does SD-WAN work?

SD-WAN or Software-Defined WAN works by abstracting many network layer functions directly into the software. It can be deployed as an overlay on top of any existing network infrastructure. It adopts an inclusive approach to wide-area networking. It can work on top of the existing traditional WAN architecture.

It gives enterprises the option of dynamically connecting branch offices and the HQ office by leveraging internet and cloud capabilities along with integrated intelligence. This makes software-defined networks much easier to deploy regionally and globally.

SD-WANs provide organizations with an end-to-end view of the entire WAN and the ability to prioritize network traffic over different connections. It measures traffic and selects the best route for application traffic in real-time. High priority and low priority traffic can be sent via different circuits. This frees up MPLS usage and can be cost-effective in the long run.

Advantages of SD-WAN

Low circuit costs

Research reveals that internet costs can be reduced with SD-WAN. You don’t have to pay as much to upgrade your bandwidth, and you can mix and match network links in a cost-effective manner. According to the content type and priority, SD-WAN can direct more traffic volume over 4G LTE and internet broadband, which is typically less expensive than MPLS services.

Cloud optimized solution

In traditional architecture, all network traffic routes to the data centers and requires filtering. This results in latency and sub-optimal routing for cloud-hosted providers such as Office-365. On the other hand, SD-WAN can directly send cloud traffic to cloud endpoints. Robust cloud-based communications complemented by SD-WAN optimizes the network so your company can fully embrace cloud computing.

Application-level routing

Application-level routing

SD-WAN prioritize crucial applications across the WAN and also provide real-time traffic monitoring for diverting critical business traffic around certain events. It also supports applications that are high bandwidth-intensive.

Centrally managed services

SD-WAN centrally manages network services in the regional database center, in the cloud, and on the customer equipment. Software-defined flexibility with business-policy abstraction and automation simplify complex configurations of policy definitions and traffic routing.

Limitations of SD-WAN

SD-WAN is still new and comes with its own limitations. Being software-defined, SD-WAN is inherently limited by the underlying circuits. If you use cheap broadband, there is only so much that intelligent routing can do. True QoS is achieved only on solid underlying network infrastructure.

This can be overcome either by in-house MPLS deployment or using an SD-WAN provider with their own private network backbone.

Some other limitations are:

  • The vendors of SD-WAN tend to vary and need to be vetted to suit your requirements
  • SD-WAN forwarding appliances offer Ethernet connections to interface with MPLS WAN and LAN, but not multiplexers. If a time-division multiplexer is necessary to support your network, you’ll need to retain your existing WAN router in order to support your SD architecture.

Differences between SD-WAN and traditional WAN

Here is a side-by-side comparison of the traditional WAN vs. SD-WAN so that you get a better understanding of how they function.

Traditional WAN


Distributed configuration: network configurations are locally housed on individual routers Simplified branch service: has a software defined-approach ensures more flexibility than traditional WAN
Failover is dependent on the state of the link, thereby forcing the users to rely on routing protocols. Cloud-first: Services that are already in the cloud will be prioritized
Device policies have to be configured individually on a per-device basis. Application prioritization: Promises quality services and provides real-time traffic monitoring in case of brownouts.
Lead time required to set up new networks at different branch offices. This requires months of planning. Lower operational costs. SD-WANs play special emphasis on high speed and low-cost connectivity. It takes advantage of connection options such as broadband and allows for the elimination of MPLS circuits.
 Heavily dependent on data centers SD-WANs have a unified bandwidth pool that is offered by different service providers. This permits greater network resource utilization.
Data centers are limited in their capacity in dealing with incoming connections to various cloud platforms Not restricted due to limitations of hardware comprising the network

How can I adopt SD-WAN?

SD-WAN solutions may be deployed in-house or can be fully managed by third-party services. You can also adopt a hybrid WAN model which integrates your current infrastructure with SD-WAN. As a leading telecom service consultancy, CarrierBid experts can help you find the most efficient and cost-effective solution that works for you. Contact us to schedule a free consultation today!

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