Unlocking the power of SD-WAN: Advanced traffic engineering, path selection, and AI integration

Corporations are increasingly deploying software-defined wide area networks (SD-WANs) to optimize network performance, as well as increase their flexibility and security.

At the heart of an SD-WAN’s architecture is a new way of managing diverse WAN links, such as MPLS, broadband, and LTE. By separating the control plane from the data plane, it allows for the management of multiple physical and virtual WAN links in a single, logical interface. The SD-WAN directs traffic depending on the level of network congestion, optimizing network utilization and resilience.

This post explores foundational SD-WAN concepts, advanced routing techniques, and AI-driven traffic optimization, to highlight how SD-WAN enhances both performance and security in dynamic network environments.

Beyond load balancing: The need for advanced traffic engineering in SD-WAN architecture

Load balancing alone cannot fully leverage the potential of an SD-WAN. While load balancing is useful for distributing traffic across multiple links, it lacks the ability to optimize for specific application requirements or network conditions.

Advanced traffic engineering techniques can improve traffic efficiency. Below, we discuss application-aware routing, dynamic path selection, and quality of service (QoS) policies as methods that prioritize high-priority traffic such as VoIP and video conferencing; all three ensure the SD-WAN meets real-time demands based on both application needs and current link performance.

By applying these advanced techniques, the SD-WAN provides insights into the best network for transmitting video via public, private, or combined networks in the most efficient manner and with the lowest latency.

Foundational understanding of an SD-WAN

An SD-WAN routes traffic according to real-time network circumstances and application requirements for optimal control and performance.

A key aspect of any SD-WAN is separation. The control layer is centralized and detached from the underlying hardware, enabling centralized management and more efficient WAN operations. This architecture allows network administrators to create and enforce policies across the network from a single control point, streamlining traffic management and policy implementation.

Rather than depending on conventional static routing where traffic follows fixed paths even if conditions change, the SD-WAN provides a routing mechanism that continuously adapts to present circumstances, enabling real-time decision-making and business policies.

An SD-WAN also optimizes data flow to satisfy performance criteria, for example, lower latency, less packet loss, and higher bandwidth efficiency. This entails intelligent path selection, or “per-packet path selection,” where the SD-WAN continuously measures the performance of all available links (MPLS, broadband, and LTE) and performs load balancing.

This process is influenced by:

• Link quality metrics, e.g., latency, packet loss, and jitter
• The priority of the application, e.g., real-time services like VoIP or video conferencing versus background data transfers
• Predefined business policies that govern traffic handling for mission-critical applications

High-priority applications such as VOIP are directed over paths with the best performance, while less critical traffic is routed through standard or backup links.

Traditional routing methods and their limitations

In traditional wide-area networks, routing mostly involves the application of fixed rules or simple metrics, such as hop counts or predetermined high-priority paths. These simplistic approaches ignore the complexity, minuteness, and ever-changing character of network traffic.

While such practices might have been deemed adequate a decade ago, they are no longer sufficient in today’s complex enterprise environment of ever-changing traffic patterns due to cloud services, remote work, and multi-application usage.

One of the major constraints of traditional routing is that it ignores real-time changes in networks. Routes are created in advance and do not consider geographical or time-based variances in link congestion or application needs. This rigidity leads to performance deterioration, including increased delays, packet losses, and network traffic clogging at peak traffic times.

To achieve reliable, high-quality routing, more sophisticated routing policies based on an SD-WAN and other technical decisions are required. These will create policies according to the real-time state of your infrastructure and application needs.

Advanced traffic engineering techniques for an SD-WAN

Advanced features such as dynamic weighted least congestion (DWLC) and multi-exit discriminators (MEDs), application-aware routing, and quality of service (QoS) enhance efficiency by prioritizing traffic based on application needs and network conditions.

Dynamic path selection

Unlike routing with static paths (pre-planned routes), dynamic path selection continuously measures various factors such as network characteristics through a process guided by performance metrics. This feature guarantees that paths used for traffic at any given moment do not fall short of the best routing available by considering factors such as link utilization latency, jitter, and packet loss.

This method is the best option in situations where network performance cannot be guaranteed. Intermittent bandwidth changes, physical network congestion, and sudden spikes in packet loss on particular WAN links are just some of the factors that can alter network quality. With dynamic path selection, SD-WAN will automatically reroute traffic to the best available links. These real-time adjustments optimize network performance and reduce downtime for critical applications by preventing congestion caused by varied traffic types and volumes across the enterprise.

Dynamic weighted least congestion

The DWLC algorithm minimizes the path delay by continuously evaluating various alternative routes, which are assigned a weight based on performance factors such as the congestion level of each link. This helps ensure that network traffic is routed on less-congested paths to prevent bottlenecks.

The DWLC feature intelligently adjusts traffic distribution based on real-time network conditions. For example, if one WAN link gets busy, DWLC will detect this and automatically switch routes, guaranteeing optimal performance for delay-sensitive applications like VoIP and video conferencing.

DWLC also helps properly manage network resources because traffic is always routed via the most effective and dependable route that is available at that time.

Multi-exit discriminator

(MED) is an extended path selection process within an SD-WAN environment, primarily where there is more than one exit point out of an autonomous system (AS).

The multi-exit discriminator values are numerical preferences assigned to different exit points in a network, helping to prioritize specific paths for outbound traffic. The SD-WAN controller changes these values according to various factors such as bandwidth congestion levels, link performance, or distance from the destination, ensuring that traffic is redirected at the best exit.

In large companies with several data centers, such as global enterprise networks, MED is useful for pushing traffic to the closest or least busy data center. This decreases latency and improves application performance, which is key for applications and services that require prolonged communication links.

MED works even when there are multiple exits located throughout a network, selecting the ideal route based on real-time metrics.

Application-aware routing

In most of today’s enterprise networks, applications may depend more or less on network quality or vary in terms of sensitivity. For example, VoIP, video calling, and money transactions are all critical applications that require a constant and enhanced connection to operate as expected; these thus require low levels of downtime or disruption. On the other hand, file transfers and emails are not considered very urgent, meaning there will not be any catastrophic consequences for slight delays.

Application-aware routing is where an SD-WAN tracks the performance of different applications and adjusts the path accordingly. It also enables an intelligent understanding of how distinct applications function, allowing the SD-WAN to identify unusual traffic patterns that may pose a potential threat to data flow.

For example, valuable VoIP connections that need to be used in real time are very susceptible to latency and loss of packets, so the routes taken must be rapid and trustworthy. At the same time, less important and less pressing data traffic will be given a lower priority to decrease unnecessary network usage and leave it available for higher-priority applications.

Quality of Service (QoS)

To augment network performance, an SD-WAN monitors the health of various connections with active QoS policies. This enables consistent performance irrespective of the network in use.

With these policies in place, the SD-WAN can dynamically adjust to network conditions, unlike traditional networks with fixed configurations. If the network slows or segments become congested, the SD-WAN automatically redirects traffic to paths that meet QoS standards.

SD-WAN orchestration and automation

As networks become more complex, it becomes difficult to manually manage traffic and pick the right routes. That’s where an SD-WAN’s orchestration and automation step in. By automating everyday network tasks and managing traffic across different locations, an SD-WAN helps businesses keep their operations running smoothly while their networks grow.

Key features of an SD-WAN that support this include its support for multi-site connections using SD-WAN fabric and cloud-based management (control, orchestration, and automation). It also controls traffic flow automatically, dynamically redirecting traffic based on preset guidelines and real-time data, without constant IT intervention. This reduces congestion, improves IT efficiency, and minimizes interruptions across the network.

Integration with network security

As traffic moves between different branches, data centers, and cloud environments, an SD-WAN needs to combine advanced traffic management with strong security measures to keep the network safe without slowing it down.

SD-WAN architecture makes security a priority via firewalls, intrusion prevention, encryption, and other attributes. IT teams can manage these security measures from a single place for easier end-to-end network protection. With built-in security, the SD-WAN ensures data remains protected without compromising network speed.

Impact of AI/ML on traffic optimization

Artificial intelligence (AI) and machine learning (ML) are playing a growing role in shaping how SD-WANs handle traffic.

AI-powered analytics give companies valuable insights into long-term traffic patterns, making it easier to predict future network needs and scale infrastructure accordingly. ML algorithms, which can process large amounts of data in real time, can detect patterns and anomalies easily missed by the human eye.

These technologies enable SD-WANs to go beyond simply reacting to issues to predicting what’s coming and adjusting traffic flows before problems arise. This reduces bottlenecks and optimizes network performance in real time by analyzing both past and present data.

Ai and ML also allow an SD-WAN to constantly improve its ability to make better decisions about directing traffic, which keeps the network reliable, adaptable, and able to handle changes smoothly.

Conclusion

More and more companies are turning to SD-WANs, as they realize just how important smart traffic management and path selection are. To make the most of SD-WAN infrastructure, businesses need to move beyond old-school routing methods and embrace advanced techniques like dynamic path selection, application-aware routing, and QoS policies to optimize traffic flow and ensure critical applications run reliably.

Integrating orchestration and automation into an SD-WAN enables real-time adjustments and gives you centralized control. With AI and ML capabilities, the results are even better by predicting potential network issues, spotting trends, and automatically fine-tuning traffic.

Smarter system management not only keeps up with day-to-day demands but also helps meet your long-term business goals, making an SD-WAN a key solution for companies that want more flexibility, scalability, and efficiency.