How to Speed Cloud Apps Around Network Traffic with SD-WAN


SD-WAN speeds cloud apps around network trafficI’ve been thinking lately about similarities between cloud-connected networks, SD-WAN, and the commute to my workplace. I’d like traffic to flow smoothly and travel time to be predictable in both directions every day at whatever time I choose to drive. Unfortunately, reality falls short of this for most people, including me, who commute in metropolitan areas, whether by automobile or mass transit.

I have a primary route that usually works well. But it doesn’t take much—an accident, a rainstorm, or repairs—for one of the roads to become congested. Last week, a traffic light on an expressway reset to a blinking, four-way stop that added 10 minutes of “bumper meditation” to my commute. (Om— Om— Om—)

Improving the commute

Everyone who drives to work needs alternate routes. If you take mass transit then you need a “Plan B” for days when the trains and buses are running late or not at all. It’s even more important to see a problem ahead before you get stuck in the middle of it.

I make a habit of checking traffic maps on my smartphone and adjusting my route as needed. But I sometimes forget and end up in a traffic jam. A better approach is to use an application that proactively warns of traffic congestion and suggests alternate routes. The ideal solution would be a self-driving car that knows my preferences and automatically makes adjustments to put me on the fastest path to the office.

So, what does my commute have to do with cloud applications and software-defined WAN (SD-WAN)? There are actually a lot of similarities. Let’s start with the cloud applications.

Cloud applications and public networks

For many of us, productivity depends on cloud-based applications. I use cloud-based email, file storage, content-sharing sites, and many other services. Having reliable, smooth-flowing network connections to the cloud is necessary to get my work done.

Most organizations use the Internet to connect with cloud applications. Unfortunately, relying on public networks can be like commuting in a metropolitan area. There are no performance guarantees and traffic congestion can be an issue. The user experience with an Internet-connected cloud application may be good most of the time but it can also be unexpectedly poor.

The private connection alternative

One way to address this issue is to bypass the Internet and set up a dedicated connection with guaranteed bandwidth (e.g., MPLS) from your enterprise to the cloud vendor. You have to pay a premium for this service, like using a fast toll road to get to work. AWS Direct Connect and Microsoft Azure ExpressRoute are examples of dedicated connection services.

Organizations that do this are generally large because one typically needs a lot of users to justify the cost of a private connection to the cloud. They often set up one connection from a central location and route cloud application traffic across the enterprise network to end users.

This approach works well for application users located near the on-premises end of the dedicated connection. However, users at remote sites may experience consistently slow response times because their network packets must travel a long way before getting onto the high-bandwidth link. For them, one performance issue has been replaced with another.

Speeding around network traffic with SD-WAN

SD-WAN steering application trafficSomething like my ideal solution for commuting is needed with networks that connect to cloud applications. We can start by setting up alternate paths. A branch office, for example, can have WAN uplinks through multiple Internet service providers as well as a path through the enterprise network to another cloud uplink.

Next, we need a way to monitor the paths and steer application traffic down the best one in real time. This is where SD-WAN comes in. You could, for example, set up an SD-WAN rule to monitor the latency of alternate paths connecting a particular site to the cloud. Then SD-WAN will automatically steer traffic down the fastest path at any given time.

It’s worth noting there is an underlying assumption here about safety and security. When on the road, we’d like to get to our destination quickly but not at the risk of injury. Likewise, any network path to the cloud must be secure to prevent sensitive information from falling into the wrong hands.

Advanced traffic management

What I’ve described so far is a simplistic representation of the way SD-WAN works. It’s actually a powerful tool that goes well beyond improving network performance for the users of cloud applications. SD-WAN actually changes the way cloud-connected networks are designed, deployed, and managed.

Let’s zoom-out and think from the perspective of system-level management. Returning to the commute metaphor, one of the freeways where I live is reserved for cars and light trucks; no semi-trailer trucks allowed. Expressways and freeways also have special lanes for vehicles that carry more than one person. Some of the trains that travel at peak hours stop only at stations where large numbers of passengers get on or off.

My point is that traffic management—whether for roads, trains, or networks—involves trade-offs. Priorities need to be set and applied as policies. SD-WAN automates the implementation of policies governing performance and security for applications, users, and sites.

For example, latency-sensitive traffic (e.g., VoIP and web conferences) should always be steered onto the fastest network paths. File back-ups can be assigned a lower priority as they are rarely time-sensitive and can clog network links. Also, certain classes of confidential application and user traffic should be sent only via the most secure network connections.

Implementing policies on cloud-connected networks using legacy management tools is an error-prone, labor-intensive exercise because it is typically done with command line interfaces on a device-by-device basis. In contrast, SD-WAN centralizes visibility and control into a single, point-and-click management console. With automation, a network administrator can create a new policy in a few minutes and apply it instantly with consistency across the entire network. How’s that for efficient traffic management?

Now, if I could apply SD-WAN to my commute then every workday would start off well!

More about SD-WAN

Learn more about the way SD-WAN is reinventing how cloud connected networks are designed, deployed, and managed.

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