Controlling Priority Traffic with SD-WAN

SD-WAN offers many benefits for organizations looking to modernize networks around applications.

Controlling Priority Traffic  with SD-WANYesterday I was at the airport waiting to board my flight home to Chicago. My group number was 4. This means I’m uncomfortably standing for more than 20 minutes waiting for my number to be called. But I’m in good health, of able mind and body and traveling by myself, so waiting isn’t really an inconvenience so much as a rule within this context that needs to be followed.

As I was standing around, a young family headed straight to the front of the line without regard to their group number. They were allowed to board the plane. Why? Well, because that small family is important. Not only due to their young passengers, but because it makes the most sense for everyone on the plane to have them board and get comfortable first so everyone else can effectively do the same.

This priority boarding analogy is extremely similar to what SD-WAN promises to bring a network.

What Is SD-WAN?

Software-defined wide area networking (SD-WAN) creates an overlay network that is used in tandem with any existing network infrastructure to create an application-centric experience for users accessing the cloud. At its base level, SD-WAN promises a control center around application priority for all traffic moving outbound from the existing WAN. This means you can prioritize your traffic on your IP voice data packets or your customer relationship management (CRM) tool data packets vs. your general internet browsing traffic.

Benefits of Using SD-WAN

As organizations move more workloads to the cloud, the scalability and real-time performance of those clouds becomes critical for realizing ROI and creating smooth experiences for employees and customers.

The fact that SD-WAN can layer on top of any type of existing network gives the tool a tremendous amount of power for IT organizations looking to move toward a network refresh initiative.

  • SD-WAN has the ability to prioritize traffic on dedicated and scalable symmetrical bandwidth in addition to asymmetrical best effort connections that are cheap but effective.
  • SD-WAN allows many organizations to lean away from legacy multi-protocol label switching (MPLS) ports, which not only saves many organizations money but also gives them more scalability in regards to how they provision bandwidth across their WAN.

To be clear, SD-WAN can be used in conjunction with MPLS, as many remote or ancillary network sites that lean more heavily on SaaS applications vs. communicating with a private data center asset may not need MPLS ports provisioned. In that case, moving to an SD-WAN model with cheaper or more scalable bandwidth might be  a perfect fit. Organizations can also go straight into SD-WAN as the primary network overlay, or utilize its features and functionality over a virtual local area network (VLAN).

As far as a user interface goes, network managers are given access to the SD-WAN orchestrator. This SaaS-based orchestrator allows network admins to look up graded health scores of all their individual connections to troubleshoot across connection and ingress/egress delivery.

Understanding Power Rankings

The main star of the show is what I like to call the power rankings. Think about the AP college football top 25. That list of teams is refreshed every week depending on the results of play and how important each team is viewed in terms of performance ability.

On SD-WAN, you receive a top 25+ ranking (the list can be infinite with some providers) of all the applications detected on your network, with a simple drag and drop methodology to rearrange and prioritize as needed. This means your most critical applications can always receive egress priority on your network vs. something like Facebook or YouTube video traffic, which may consume a lot of real-time bandwidth but doesn’t have much to do with an organization retaining and driving value and/or revenue.

How Is SD-WAN Deployed?

SD-WAN is typically deployed as an appliance daisy-chained to the router at each site that is utilizing the service. In some cases, there may be a hot/cold spare chained into the network as well. There is also the option to deploy SD-WAN as an appliance on Whitebox x86 hardware within a data center or colocation facility. This is a common feature of an organization that is leaning heavily on a hypervisor to deliver value.

Additional SD-WAN Features to Consider

There are a few other features that SD-WAN provides that are inherent to the service in most cases, but in others offered up as optional.

  • Bandwidth aggregation: Let’s say you have a 1Gb dedicated circuit and a 150/25 coax circuit. An SD-WAN appliance essentially aggregates all of these circuits together into one circuit. The main benefit here is that secondary/tertiary connections are no longer waiting for an emergency but are being used in real time at all times.
  • Data packet cloning: If an organization considers some of their outbound data packets to be extremely important, an SD-WAN appliance can clone those data packets over multiple connections and deliver out from whichever connection happens to have the best upload. The other data packets are simply discarded. This is a great tool for scheduled network events like disaster recovery backups.
  • Network segmentation: It’s possible that there might be some types of traffic you only want riding over a private connection vs. a best effort connection. SD-WAN orchestrators allow you to set rules about what applications ride which pipes. A common setup here is to send all non-critical traffic, such as general internet browsing, over a non-critical connection.
  • Firewall services: Most SD-WAN appliances have a firewall in them. This is great for a small remote site that only need an off-the-shelf firewall. It’s not a carrier grade firewall, and I have seen many customers turn them off and use their cloud-based firewalls instead, but it’s a nice bonus for someone on a budget.

SD-WAN offers a lot of benefits with a network refresh initiative for organizations looking to modernize their networks around applications. As IT shops deal with the ramifications of remote work and edge compute, SD-WAN overlays will continue to be a critical component of a networking toolkit, and will find new life and use cases as computer-based work evolves.

Join us as we take a look at more use cases and features of SD-WAN in future articles. These articles are meant to help you understand why SD-WAN is a core component of putting your CompTIA Network+ certification to good use. And maybe, somewhere along the way, we’ll figure out a way to deboard a plane in the most effective way possible (spoiler alert: Add another jet bridge). Next time we’ll cover SDN, SD-WAN and VNF. What’s the difference and why should you care?

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