VoIP Voice Quality: Not There Yet, But Not Too Far Away

I’ve heard and read many complaints about the voice quality of a VoIP connection…both residential and business. Is this real or memorex (so to speak)? What are the REAL issues…and where are we (especially businesses) headed with the maturing of VoIP?

The problem remains that our IP networks are based on packets. This is efficient for moving data, but not so good for time and stream sensitive traffic.

In private networks, we can tune communication elements for session-centric vs. packet-centric performance. We make sure we have enough bandwidth to allow a smooth flow of session traffic (VoIP, for example), adjust prioritization so session traffic gets priority, change our balancing and routing to ensure sessions follow a symmetric path constant. The result is less efficient use of our bandwidth capacity, but a higher quality session for users. In short, we are moving away from a purely packet delivery approach and towards a channel-like network.

Through the Internet, we lose the ability to optimize the traffic of our session. The Internet is, by design, application neutral. The focus is on package delivery, and every package is just as important as any other package. At each step of the communication path, devices tune to receive a packet, determine which port to send it to next, and move it on its way. Load balancing across multiple paths, each packet to a given destination can take a single path. The criterion for success is error-free packet delivery.

So what is likely to happen? I expect prioritization of session traffic over carrier networks. They will implement it for their own services first, and the cost of doing so will be recouped from the revenue of that service. It will be available to individuals, businesses and competing service providers as a premium service. After all, it’s a level of delivery above what simple Internet access promises. For it to work, carriers will have to agree to respect each other’s prioritization when traffic moves from one carrier to another. This will likely be no different than your current method of driving others’ traffic from the business sense, and the engineers will quickly sort out the technicalities. VoIP service companies will shout that this is not fair, that their service is simply using the bandwidth paid for by their customers’ access fees. However, session prioritization is not what your clients have signed up for, so their complaints will be ignored. A new level of access will become common, possibly called Voice Assured or something along those lines.

At some point, either a new startup trader or an existing trader will decide to market session priority as part of their standard level of service. If enough customers switch to get this, the other operators will follow suit. At that point, most networks will have become priority sessions like the standard build.

Big Iron will not benefit from all this.

Some session service providers will lose out to operators because their business model is based on the performance of a competitor. Some will step up and pay for session priority so their clients don’t. If they can survive on thin margins until session priority becomes the norm, they will retain their customer base.

(Q) Has anyone experienced poor quality calls using VoIP?

Yes, of course, most people have done it knowingly or unknowingly. VoIP traffic across all delivery methods: Skype, Vonage, Cable, IP-PBX, Peer-2-Peer, softswitches, and CO… have varying degrees of voice quality issues in their VoIP experiences. For now.

(Q) Is this a case of poor equipment, poor software, bad connections, or what?

This is a very broad topic. Too many people expect to “just plug it in” and it will work, however “it” is defined. The same goes for VoIP due to marketing, glitches, poor judgment, and inexperience.

There are many other reasons as well: DSPs that are improving (done), software getting heavier that fixes existing known issues and maybe creating some new unknown ones yet (I think), connections: some on the cables, connectors themselves, but it’s all relevant to what is defined as VoIP, which is just a protocol, what about all that other stuff to access, control and transport those packets?

So keep in mind that a vast majority of “phone lines” are copper, TDM based. Longer loops have increased loop current levels and mixed with IP – you get echo.

The “list” of problems or causes and effects is mind-boggling. It’s not simple or black and white – the short answer is “it depends”.

Once VoIP can meet those “just plug it in” expectations, we will undoubtedly be in a new world of telecommunications. It is a journey and it will be an adventure for those who make it through. It will be interesting to see and experience how it all unfolds.

(Q) Do you think subpar voice quality will be a limit to the growth of VoIP?

No. Less than toll quality is not a VoIP metric for business or carriers (Big Iron) or the softswitch world either. VoIP as a whole is getting better, at least so the media says. 🙂 Call quality is moving away from what we do, for example, with software and a device to monitor voice packets, equipment and other things… to monitor call quality integrated within the software itself by informing through the network. This is significant when it becomes the norm; so, less expensive solutions for monitoring, packet shaping, and directing voice packets to their final destinations on time will noticeably change quality, MOS scores, etc. Who can afford existing tools besides Big Iron and L-Enterprise?

(Q) If poor voice quality continues, could this cause a backlash against VoIP and a return to Big Iron for some businesses?

Not likely. Too much has already been invested and proven in the way operators successfully deliver VoIP traffic without the end user knowing that they are, in fact, on a VoIP segment or call. Ethernet Layer 2 provides a slightly cheaper delivery method over TDM and since cost is always a factor and as “techniques” improve so will delivery. A “recall” is not likely to occur.

(Q) What can be done to bring VoIP voice quality up to pay grade?

It depends on what audience you are targeting. From where I sit:

1) Training – Certification – Field experience for those who implement VoIP;

2) Metrics that measure not only MOS, but also actual voice packets for jitter, latency, etc. and then the responsibility in the missions of those who make the decisions: did we achieve our objective and what were the real costs in doing it and how did it impact? us?

3) Time: the hardware is not getting worse, it is getting better. (That’s a fact) The industry is on a learning curve, one that is not going to plateau because delivering VoIP in any form factor is challenging, not for the faint of heart. (Implementers)

4) User Expectations – This is one of the biggest failures not only in VoIP, but also in the delivery of any telecom/IT service or solution. Expectations are not set and there is a constant failure of “meeting of the minds”.

5) Benchmarking vs. Hook-Line-Sinker: Instead of ramping up all the effort for VoIP transitions, organizations should first establish some benchmarks. The temptation to go big versus small because leaders within the organization need to achieve big success (cost savings).

6) QoS, access, transport, infrastructure – all this applies to any VoIP user.

Before you jump in, get up to speed and go into more detail about what you want, delivery methods, metrics, how VoIP is planned before you sign a deal or make a change with someone promising something better, faster, cheaper , as with anything.

VoIP is here to stay. Sink, swim or paddle: it’s rewarding, it’s a beast to handle, challenging and very rewarding for those who are prepared.