SD-WAN can provide Quality of Service over the Internet

SD-WAN can provide Quality of Service (QoS) over the Internet

Organizations have tried to make voice services work over Internet Protocol (IP) network pipes (aka Voice over IP or VoIP), there have been very basic requirements in order to make it operate effectively. The first item needed for IP based voice was a dedicated, business class network line to carry this sensitive traffic. A business class circuit was paramount to reliability and uptime required for a crucial service like voice. This type of network access has low latency characteristics which keeps the amount of time it takes to forward the voice traffic low so that conversations are not made off kilter by long delays. Also absolutely critical to voice over network pipes is an additional layer over these high quality dedicated connections, something called quality of service or QoS. QoS is a suite of bandwidth prioritization and reservation techniques that give select services fast lane access to bypass lesser classifications of traffic and also reserves bandwidth preventing exhaustion of available throughput. Most commonly, QoS is used in tandem with carrier services like an IP VPN or Multi-Protocol Label Switching (MPLS) and have been assumed by many to be the only way to reliably deliver voice services for an organization. I can affirm as a network engineer for the past few decades, this has been the case for most of my career. In order for voice to perform adequately, specific care was required to spec out dedicated pipes with prioritization and if you didn't, you were typically asking for trouble in the way of poor quality, disconnections and general voice issues. That is until a thing called Software Defined Wide Area Networks or SD-WAN came along. This nascent technology space is drastically changing the way we do a lot of things on the wide area network, including managing sensitive real-time protocols that require QoS.

Video quality can suffer if the network can’t meet its high bandwidth needs. Video conferencing can take on many forms and protocols. For enterprises that have experienced problems, such as delay and jitter on voice over IP platforms, you know some platforms are better than others. The big variance in supporting video conferencing requirements is the integrity of traffic over wide-area connections.

Let's take a look at some of the things that make SD-WAN different versus how we've implemented voice over traditional networks up until now. These are items that are truly differentiators from means we used in the past to run network traffic over both tried and true dedicated lines not to mention over the commodity broadband or specifically configured Dedicated Internet pipes.

1.   Multi-Path Steering - SD-WAN can actively forward over multiple lines and is constantly measuring the characteristics and properties of each path available. Because it can very rapidly identify issues like high latency, packet loss and jitter, there are software mechanisms to quickly bypass these issues by utilizing an alternate path on the fly.

2.   Forward Error Correction and/or Packet Duplication - When issues like data loss from dropped packets arise, if there is only one path available or all paths are experiencing loss, that can be a serious issue with traditional networks with little means to remediate. SD-WAN employs features such as Forward Error Correction (FEC) or Packet Duplication which once packet loss is identified on a path, will send duplicates of the same packet to have greater assurance that critical data like voice or video will make it to their destination. At the other side of the SD-WAN connection for that voice or video stream, the first packet received will be sent along and the duplicates will be dropped.

3.   Jitter Buffering - Voice and video quality can suffer from a network condition called "jitter" which is when the information sent over the network is spaced inconsistently leading to a variable tempo for the stream. The result is audio or video that can have gaps, speed up then slow down and generally become impaired. SD-WAN measures the gaps between the packets and can evenly space these packets on the other side providing what is called a "jitter buffer" to realign the timing of these packets to keep the video or audio stream cadence intact.

4.   Prioritization and Queuing over Multiple Paths - Because SD-WAN performs it's queuing and packet forwarding over something called an "overlay", the forwarding decisions for information that has the highest priority and reservation of bandwidth for applications is performed at a layer above the traditional IP interface. With this, a priority "fast pass" can be given to crucial data like voice, video or other business essential apps bi-directionally and this can be done over all paths available.

So as you can see, there are many pieces that come together to make IP based voice over broadband and Dedicated Internet Access (DIA) is now possible. WAN Dynamics has designed many SD-WAN based solutions for customers and has seen it perform in the "real world" so can attest that IT WORKS! 

The following are some of the more prominent examples of reasons for SD-WAN we've been able to assist with to date:

1.   Voice Services Over the Internet - A lot of small to medium sized businesses have started utilizing voice services over commodity broadband connections with no Quality of Service (QoS) in place. Though most of the time this works adequately, there will be many instances of degradation in quality or dropped calls that can be frustrating. This has just been the reality of utilizing the public Internet for voice services... up until now. With SD-WAN, we're able to prioritize voice traffic both inbound and outbound while leveraging multi-path technologies to "route around" carrier backbone problems. We're able to do this with single, stand alone sites in addition to multiple locations.

2.   WAN Visibility and Management - Setting aside the benefits of multi-path link steering, bandwidth aggregation and QoS for a bit, many organizations have no usage breakdowns or application performance visibility in their network today. As a byproduct of the application steering and prioritization baked into most SD-WAN solutions, there is a great deal of reporting functionality available. So now when stakeholders of IT want to know what is happening at their remote locations, they have a graphical interface to see exactly what is happening.

3.   Configuration Uniformity and Standardization - Large organizations which have many sites or will soon have many sites at the hands of rapid growth can have a lot of hands in the IT group working on things. With this, lack of standardization becomes an issue as sites are configured and turned up if there is not a uniform configuration policy. With SD-WAN, attaining a high level of uniformity is simple using features like Zero Touch provisioning and Configuration Profiles to make sure that all sites are configured identically. This also helps greatly for change management if you want to make a configuration update to all of your locations. With this approach, you can update a configuration in one place and push it to all sites, instantaneously. This frees up engineers to solve larger problems facing the business rather than making a minor configuration change on dozens or hundreds of sites.

4.   Remote Diagnostics Capabilities - When there are issues at a remote location, it can often times be difficult to walk users through providing troubleshooting assistance or getting the right software and hardware onsite. With the built in tools into many SD-WAN solutions, the ability to perform packet captures, see network state and what the users see on the network, so that the time vetting issues on the network can be greatly reduced.

5.   MPLS / IP VPN Replacement - MPLS and other dedicated private network infrastructures have begun to outlive their usefulness with many organizations as critical workloads are moved to the cloud. Further, there is growing demand by companies to reduce cost of their expensive WANs that typically have no redundancy or application smarts built in. SD-WAN can easily leverage existing dedicated internet access (DIA) links and even inexpensive broadband connections to build an application aware, private network overlay that provides more applications control, redundancy and critical business application prioritization than traditional network designs.

These are just five examples of things we have been able to help with. We're happily conducting Proof of Concept deployments for businesses to show the value of SD-WAN and finding new use cases all the time.

"By the end of 2019, 30% of enterprises will have deployed SD-WAN technology in their branches, up from less than 1% today."