QoS is still valuable

The world may be overlooking some fundamental lessons it learned in the early days of networking

Articles published December 12, 2018 by Sarah Verbeck

As the world of enterprise telecom evolves, there has been an increasing emphasis on user and application mobility. More and more business applications are moving to the web, or to remote thin client solutions like Citrix. More employees are working from home, or from small remote branch offices using virtual private network (VPN) tunnels. Additionally, more businesses are embracing the advent of software-defined networking in a wide area network (SD-WAN), replacing their old, expensive, multiprotocol label switching (MPLS ) circuits with intelligently bonded broadband internet and dedicated internet access (DIA) circuits.

One of the major forces that has paved the way toward this paradigm shift has been the concept of Over-the-top (OTT) delivery solutions. Historically, phone, internet, and video services generally operated and were acquired independently of one another, with each having a dedicated media and infrastructure to support it. Today, however, we’ve transitioned to a world where all our data, video and voice services can be delivered conveniently OTT with a single internet connection. A great and simple example of this is how we’ve transitioned away from cable TV in favor of streaming services like Netflix.

When it comes to business voice, gone are the days when users had to be physically present at the office to receive calls on the corporate phone system. Remote office or home users can now smoothly operate from virtually anywhere as long as they have an internet connection. Office workers can have as much mobility as their company will allow them. One might say that technology is no longer the primary inhibiting factor to sustaining a mobile workforce — it’s workplace culture that needs to catch up now. The technology is here.

From a holistic perspective, these developments constitute exciting progress. The telecom world is undoubtedly changing for the better in terms of improving user mobility and overall network resilience. However, one concern when it comes to voice services, the world may be overlooking some fundamental lessons it learned in the early days of networking — namely, the value of QoS.

For those who don’t know, QoS stands for “quality of service.” Broadly speaking, in telecom QoS refers to the practice of setting up rules in the network to ensure that certain traffic is given preferential treatment over other traffic if the network is saturated.

Here’s an analogy. Let’s say you’re at the airport, waiting to board a plane. You’re standing in a long line, with your economy-class ticket, waiting along with everyone else for your turn to board, and people can only be boarded as fast as the airline employees can process your tickets. However, at any given time, someone with a first-class ticket can arrive and cut to the front of the line to receive immediate attention before everyone else.

That’s QoS in a nutshell. Each person in the line holding a ticket represents an IP packet. QoS allows us to give certain important packets (such as voice traffic) a “first-class ticket,” permitting them to cut in line and be forwarded out before other packets.

Now, imagine there is a super long line (i.e., lots of traffic), and there is only one airline employee processing tickets (i.e., circuit demand exceeds circuit capacity). Now imagine that ticket classes are not being honored; everyone is treated in the same first-come, first-serve basis, regardless of the ticket type they are holding. For example, a man gets in line holding a first-class ticket and is frustrated that he has to wait with those who don’t have first-class tickets. In this situation, everyone waits like everyone else.

That’s what the network looks like without QoS. The truth is, if you are a voice packet, it’s imperative that you get on that plane as fast as possible because if you’re too late, the users talking on the phone are going to hear garbled/stuttering audio. This translates into unhappy users.

To implement QoS between two endpoints, you need to be in a position to control those endpoints, along with every point in between — all the airports, so to speak. Each of those airports needs to be properly trained to honor ticket classes, or at least have a ridiculously high staffing level. While this may sound daunting, it is something we can easily control over a private circuit, since we own all the airports.

But in an open internet environment where we don’t control all the airports (endpoints), it’s a different story entirely. Different airports are operated by different companies, according to different sets of standards. Once a packet leaves our airport, we have virtually no control to determine which airports that packet is going to pass through on its way to its destination.

So, what does this all mean to you? Simply put, in a world where mobility and telecommuting are becoming more and more popular, remember that OTT voice is not the best solution in every situation.