Search
Close this search box.

Blog

Is WAN Optimization Still Relevant in the Era of SD-WAN?

Is WAN optimization still relevant? That depends upon how the WAN is utilized and the characteristics of the data transferred over it.
February 19, 2021

Is WAN Optimization Still Relevant in the Era of SD-WAN?

In the early days of IP WAN’s, bandwidth was limited and expensive, and a vibrant WAN optimization industry arose to improve WAN efficiency and throughput. In today’s era of Internet-based SD-WAN, bandwidth has become plentiful and economical, lessening the need for optimization techniques such as data deduplication (caching) and compression. And many other WAN optimization features have been incorporated into SD-WAN platforms, including traffic shaping, rate limiting, and forward error correction. This begs the question of whether WAN optimization platforms are still relevant today. The answer depends upon how the WAN is utilized and the characteristics of the data transferred over it.

Distance Introduces Latency

Although the modern WAN landscape is quite different than it was in the 1990’s, one thing hasn’t changed: WAN’s can span large distances, and distance introduces latency. Consider a hypothetical company with offices in Boston and Los Angeles, about 4200 km apart. The theoretical minimum round trip delay over that distance is about 42 milliseconds (assuming a perfectly straight path and limited only by the speed of light in an optical fiber). Suppose I want to transfer a 25 GB video file between these locations. If I have a 1 Gbps WAN link, assuming I can use 100% of that bandwidth, I could transfer the file in about 200 seconds (less than 4 minutes). If I have a 10 Gbps link, I could do it in 20 seconds. If I had a 100 Gbps link, I’d only need 2 seconds. Sure, there would be a 21 millisecond delay before the first packet arrived regardless of the available bandwidth, but who cares about that? Throughput depends only on bandwidth, doesn’t it? Depending upon how one transfers the file, there can be a surprising linkage between throughput and latency.

Latency Can Impact Throughput

Perhaps the most common example of this linkage is the TCP protocol, which will only transfer a certain amount of data before receiving an acknowledgement from the receiver. This amount is referred to as the TCP “window,” and it can have a surprising throttling effect on WAN throughput due to latency. If I use Microsoft Windows based FTP to transfer the file, the default TCP window size is 65,536 bytes = 524,288 bits. Dividing this by the round trip delay gives us the maximum throughput I can obtain: 524,288 bits / 0.042 seconds = 12,483,047 bits/second, i.e., just under 12.5 Mbps. At that speed it will take more than 4 hours to transfer the file, even if I had a 100 Gb link!

Dealing With Latency Through Protocol Optimization

WAN optimization platforms recognize protocols like TCP and can intelligently optimize their performance in a manner that’s totally transparent to senders and receivers. Rather than waiting for the far end receiver to acknowledge receipt of a window’s worth of data, the local WAN optimizer on the sender’s side acknowledges it immediately, and this frees the sender to begin transmitting the next window of data. The WAN optimizer then bundles up multiple smaller windows into larger blocks of data and transmits those blocks making full use of the available bandwidth. On the receiver’s side the local WAN optimizer breaks up the larger blocks back into smaller windows for delivery to the receiver. The improvement can be dramatic. Suppose a local acknowledgement can be given in 0.1 milliseconds. This increases the maximum throughput to 524,288 bits / 0.0001 seconds = 5.24 Gbps. Assuming I have a 10 Gb or 100 Gb link I can transfer the file in about 38 seconds.

Complementary Technologies

Today’s enterprises are increasingly global, and locations can be scattered across multiple continents. Left unmitigated, latency due to large inter-site distances can substantially degrade the performance of certain applications and protocols. WAN optimization technology can complement SD-WAN to mitigate these issues, taking full advantage of all available WAN bandwidth to maximize throughput and performance.

About GTT

GTT connects people across organizations, around the world, and to every application in the cloud. Our clients benefit from an outstanding service experience built on our core values of simplicity, speed, and agility. GTT owns and operates a global Tier 1 internet network and provides a comprehensive suite of cloud networking services. We also offer a complementary portfolio of managed services, including managed SD-WAN from leading technology vendors.

Related RESOURCES

Blog

5 Common Ways Cybercriminals Spread Malware (and How To Outsmart Them)

There are currently around 1.2 billion malicious programs and potentially unwanted applications in existence, with threat actors deploying an average of 200,454 unique malware scripts ...
How is ESG part of working at GTT?
Blog

How is ESG part of working at GTT?

At GTT, we are passionate about supporting people – and it is that passion that drives our commitment to enhancing and growing our environmental, social ...
The Power of Training, Mentoring and Learning at GTT
Blog

Unlocking My Full Potential: The Power of Training, Mentoring and Learning at GTT

In a world where the pursuit of personal and professional excellence is a constant endeavor, I’m proud to work at GTT. Its mentoring and learning ...
DDoS attacks
Blog

DDoS Attacks in the First Half of 2024

Recent DDoS attacks including the Port of Seattle and Microsoft are showing that Cybercriminals are becoming more bold and attacking organizations regardless of size or ...
Young female engineer concept. GUI (Graphical User Interface).
Blog

How to Choose The Right SD-WAN Managed Service Provider for Your Business

Many factors can influence an enterprise's decision regarding which MSP to work with for SD-WAN, SSE and a SASE framework. But most agree on which ...
Blog

Heightened DDoS Activity: A Growing Concern in 2024

In January and February of 2024, GTT’s Security Operations Center along with Corero’s Advanced Research Team have jointly recorded a significant surge in distributed denial-of-service ...
Blog

What’s Next For Networking?

The combo of faster & more efficient connectivity with new networking technologies & insights, productivity, network performance, & efficiency will all improve, providing additional cost ...
Blog

Global Tier 1 IP Networks: Everything You Need To Know

Tier 1 IP networks are the first choice for global enterprises for dedicated, reliable & secure internet access. Learn why GTT is the ideal Tier ...
Blog

The Future of IT in Manufacturing: Managed SD-WAN Solutions

GTT offers cutting-edge Managed SD-WAN for manufacturing companies. Discover how you can take a step toward the future of Manufacturing IT and networking.

OUR GARTNER RATING

Gartner Peer Insights logo
4.2


62 Reviews

88%
as of the last 12 months

Talk to an Expert

Interested in learning more about GTT products & services? Please complete this short form to schedule a call with one of our sales consultants.

Thank you for your information. One of our sales consultants will be in touch with you.

Scroll to Top