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Is WAN Optimisation still needed now that SD-WAN and SASE are available?

While SD-WAN is an established concept which organisations are continuing to adopt, SASE (Secure Access Service Edge) is a relatively new term coined by Gartner in 2019.  SD-WAN has been delivering a range of management benefits as well as cost reduction, and SASE’s strong play on security as a cloud service gives it enhanced value in the current environment. Is WAN Optimisation still needed now that SD-WAN and SASE are available?

SD-WAN and SASE deliver significant features in terms of management and security and both provide application performance gains, however, in certain instances WAN optimisation and application acceleration continue to be important technologies for businesses suffering with latency or to improve performance issues for geographically dispersed locations.


This was borne out in our survey on SD-WAN and SASE during the Covid-19 pandemic, which highlighted the continuing importance of WAN optimisation, and the likelihood that the technology will be required to ensure performance of critical applications in certain environments for the foreseeable future.

One of the primary reasons for organisations deploying SD WAN is to improve application performance. Most SD WAN and SASE providers will have features that allow for segregation of traffic by application type, and prioritisation according to business criticality. They will also have features that offer improvements in reliability to real time traffic like voice or video. However, most will not have true application-level optimisation, instead offering only high-level WAN optimisation such as TCP optimisation. If the application protocol in question struggles to perform over long distances due to the impacts of latency, then it is unlikely that TCP optimisation alone will offer much if any improvement to performance.


Covid-19 also presented IT teams with challenges related to the performance of remote workers, and subsequently many organisations (half of those surveyed) were planning to bring forward projects to improve application performance to cloud hosted and SaaS applications.

Extending features of SD-WAN to the home, either through SD-WAN devices or clients, or a SASE platform may help in some instances (particularly VoIP or video collaboration tools), but again the improvements may be minimal for file transfers where latency is the overall limiter. This is another area where true application-level WAN optimisation can provide tangible improvements, with offerings available specific to certain SaaS providers or through virtualised WAN optimisation in IaaS platforms.

WAN Optimisation

If application performance is one of your primary considerations when selecting an SD WAN or SASE solution (and it is hard to imagine a scenario where it isn’t), then serious research should be conducted into the capabilities of the vendors being considered and the requirements of your critical applications. A simple tick box exercise would not be sufficient as the scale and depth of application optimisation can vary greatly.

There are many vendors offering SD WAN and SASE solutions, and this is not a one size fits all market, with WAN optimisation and application acceleration still having a role to play. Whether you are looking at short-term optimisation or a long-term digital transformation project, it is crucial to ensure the best match for now, with the flexibility to meet future needs. Accelerate Technologies networking and security experts can help you to map out current and future business requirements to help select the right platform and provider for your organisation.

WAN Simplified, Secured, Optimised / delivered by a combination of technologies

Secure WAN Performance

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