SD-WAN - All You Need to Know

To securely link users to applications, businesses can employ any combination of transport services, such as MPLS, LTE, and broadband internet services, through a software-defined wide area network (SD-WAN).

SD-WAN as a Service offers several benefits, including cost savings, simplified network management, improved application performance, enhanced security, and better user experience. It is especially beneficial for organizations with geographically dispersed locations, remote workers, or those looking to optimize their network performance and reliability while reducing operational overhead.

SD-WAN Overview

Since it wastes bandwidth and introduces latency, there are better options than the conventional model of traffic backhauling from branch offices to the data centre for thorough security inspection. There is a need for a better method to direct traffic from branch locations to reputable SaaS and cloud-based apps over the internet while remaining compliant with security standards of the organisations.

An SD WAN provider guarantees consistent application performance and resilience, automates traffic steering based on business intent, enhances network security, and streamlines WAN architecture. An SD-WAN employs centralised control to intelligently and securely direct traffic across the WAN to reliable SaaS and IaaS providers. This enhances the overall user experience and application performance, thus boosting the corporate productivity and agility and lowering the IT expenses.

Conventional WAN architecture vs SD-WAN

The cloud was never intended to be used with traditional WANs based on conventional routers. They often demand that branch offices backhaul all traffic headed for the cloud to a hub or main data centre where advanced security inspection services can be used. Backhaul delays affect application performance, negatively impacting the user experience and decreasing productivity.

In contrast to the conventional router-centric WAN architecture, the SD WAN router model is created to provide the highest levels of application performance while fully supporting applications hosted in on-premises data centres, public or private clouds, and SaaS services like Salesforce.com, Workday, Dropbox, Microsoft 365, and more.

Contrary to the SD WAN router, the traditional router-centric paradigm evenly distributes control across all network nodes and merely directs traffic according to TCP/IP addresses and ACLs. This old model produces a bad user experience since it is rigid, complicated, ineffective, and not cloud-friendly.

Cloud-first businesses can provide consumers with a better application quality of experience (QoEx) thanks to an SD-WAN. An SD-WAN offers intelligent application-aware routing across the Network by detecting applications. As per the need, each group of apps receives the proper security policy enforcement and QoS. Highest cloud performance gets delivered via secure local internet breakout of SaaS and IaaS application traffic from the branch, keeping all the danger aside.

Why is SD-WAN used?

Enterprises utilise the cloud and pay for SaaS, demonstrating how times have changed. Users may now access several same business apps in the cloud, serving them better than connecting back to the corporate data centre.

Because backhauling all traffic, including that headed to the cloud, from branch offices to headquarters creates latency and degrades application performance, the traditional WAN is no longer appropriate.

Without sacrificing security and data privacy, SD-WAN offers WAN simplification, lower costs, bandwidth economy, and a seamless on-ramp to the cloud with substantial application speed, particularly for key applications. Business efficiency, customer satisfaction, and, ultimately, profitability are all improved by better application performance. Business risk decreases by consistent security.

Business-driven SD-WAN versus Basic SD-WAN

Enterprise customers should ideally migrate to a business-driven SD WAN provider and platform that combines SD-WAN, firewall, segmentation, routing, WAN optimization, visibility, and control features into a single, centralised platform.

• SD-WANs are not all made equal. Many SD-WAN solutions are "just good enough" or simple SD-WAN solutions. These solutions are not intelligent enough, trustworthy enough, performant enough, or large enough to provide a superior network experience. And keep in mind that enterprise digital transformation programs might stagnate without a quick, secure, and high-performing network since they depend on apps that rely on services that depend on the Network.
• Orchestration and automation of the life cycle. The majority of entry-level SD-WAN solutions offer some form of zero-touch provisioning. A business-driven SD-WAN supports centralised configuration, making the necessary modifications possible in a matter of minutes instead of weeks or months when organisations need to deploy new apps or adjust QoS or security policies.
• Ongoing self-education. A fundamental SD-WAN solution directs traffic following preset rules, often configured using templates. The best application performance is provided by a business-driven SD-WAN under any network condition or change, including congestion and when network impairments happen. A business-driven SD-WAN reacts automatically and instantly to any changes in the state of the Network through constant monitoring and self-learning.
• Consistently high standards of service. Actively utilising several WAN transport methods at once is one of the main advantages of an advanced SD-WAN solution. A simple solution can send traffic down a single way on an application-by-application basis. If that path fails or is performing poorly, it can automatically reroute to a better-performing link. To give the best levels of application performance, it can overcome the difficulties of packet loss, delay, and jitter.
• End-to-end segmentation. Basic SD-WANs offer a VPN-like service, while a business-oriented SD-WAN offers more complete, end-to-end security features.
• Cloud application breakout through a secure local internet connection. To direct SaaS and IaaS traffic directly across the internet, many simple SD-WANs offer application classification features based on predefined definitions and manually programmed ACLs. A business-driven SD-WAN offers automated daily IP address and application definition updates and continuously responds to changes. This gets rid of user productivity problems and program interruptions.

In what ways does SD-WAN enhance network security?

The ability to increase network security is one of SD-key WAN's selling factors.

Additionally, enterprises can use SD-WAN to separate mission-critical traffic and assets from threats in other areas of the enterprise. This use case is especially crucial in industries like retail, healthcare, and financial services.

Moreover, SD-WAN solutions may come with firewall features that enable businesses to quickly install at branch offices without sacrificing security.

Network administrators could, for instance, create zones to divide the Network into segments based on identities or roles, detect and stop intrusions, perform deep packet inspection and filtering based on applications, watch over active network connections, secure connections through data encryption, record security events, and closely integrate with cloud-security features like Secure Web Gateways, Cloud Access Security Brokers (CASB), and Zero-Trust Network.

Can MPLS survive SD-WAN?

The question of whether MPLS, the packet-forwarding technology that employs labels to decide on data forwarding, will perish is one of the more contentious SD-WAN issues. The most frequent use cases are branch offices, campus networks, metro Ethernet services, and businesses that require quality of service (QoS) for real-time applications.

Most networking companies think MPLS will be around for a while and that SD WAN as a service won't completely replace its use.

According to Gartner, many firms can afford WAN expansion/updates by supplementing or replacing pricey MPLS connections with internet-based VPNs, frequently from different providers.

Enterprises can isolate the transport layer from the logical layer and become less reliant on their service providers thanks to the more straightforward operational environment and the availability of various circuits from multiple carriers.

Due to the decoupling of the layers, new MSPs can now provide WAN outsourcing services to businesses. And in response, established service providers are launching Network Function Virtualization (NFV)-based products that orchestrate and combine services (SD-WAN, security, WAN optimization). Network function virtualization (NFV) makes routing, mobility, and security possible.

Most experts predict that businesses will choose a hybrid strategy, offloading internet traffic to SD-WAN while maintaining some older applications on MPLS.

How are cloud environments involved with SD-WAN?

The desire to quickly and securely integrate cloud services is a major driver of SD-WAN growth, enhancing security and lowering traditional WAN costs.

The rising use of containers and cloud-based applications that require access from the edge is one of many trends pushing the use of SD-WAN networks.

Creating mobility between on-premises and public cloud data sources will be a key focus. In addition to increasing their use of public cloud services, businesses will see the growth of their private data centres.

What is the relationship between SASE and SD-WAN?

Gartner invented the term "secure access service edge" (SASE) in 2019 to characterise an emerging technology that provides WAN and security controls as a cloud-based service. End users, devices, Internet of Things (IoT) sensors, and edge locations can all benefit from SASE. SASE incorporates several technologies, including SD WAN as a service, Next Generation Firewall (NGFW), and Firewall as a Service (FWaaS).

WAN and network security services like CASB, FWaaS, and Zero Trust are also combined by the technology into a single, cloud-delivered service paradigm. Networks and network security "must become software-defined and cloud-delivered, driving changes in architecture and vendor selection," according to Gartner's definition of the term. The usage of SASE, it was noted, is growing as businesses switch to SD-WAN deployments and offload traffic from MPLS.

However, not everybody agrees with Gartner's description. For instance, SD-WAN is developing into SD-Branch, according to IDC analyst Brandon Butler, while SASE is more of a Gartner marketing word than a novel technology.

What are some SD-WAN pitfalls?

Notwithstanding the hoopla around SD-WAN as a service, businesses should consider some aspects of the technology. Five potential pitfalls are listed below:

• Very little cost savings
• Not integrating security technologies while using SD-WAN
• Problems with performance and implementation
• Lack of data and visibility, particularly for security
• Unpreparedness for the future by ignoring private 5G for SD-WANs

However, many of these problems will be resolved by suppliers and customers as they gain a better understanding of their SD-WAN as a service implementation as the industry trend points to more SD-WAN deployments.

Conclusion

To decide how to route each type of application traffic, SD-WAN software running on CPE (customer premises equipment) constantly checks the status of all public and private-line services. For instance, voice-over-IP (VoIP) traffic might be sent by default over an MPLS VPN service. The SD WAN Network, however, may divert that traffic to a broadband Internet or 4G LTE wireless circuit if the MPLS connection becomes overloaded. For optimal performance and cost-effective routing, the SD-WAN offers automatic load balancing and network congestion control.