Network optimization

VoIP Quality 2: the Last 100m – Devices and Network

Network optimization and the right device setup results in high quality audio for calls. This is essential – you cannot sell or serve through noise. When you are operating a call center, the reliability and quality of calls is not something that you can take a chance on. Now there are more options than ever before in how to deploy your call center infrastructure. But are they all equal in terms of impact on call quality?

There are indeed marked differences in the reliability of calls and the stability of audio quality and these are directly related to the combination of how your network is setup and the phone device deployment that you select. You can read more about how the external dependencies, due to how your network and the networks of your service providers are connected to the outside world, in the first article of this series: ‘Six factors impacting VoIP quality’. But here we focus on your network and your choice of phone devices.

The following table compares the varying levels of quality and reliability achievable for the most important deployment types for call centers. The higher up in the table, the better the achievable quality:

Device Office network setup Achievable quality – explanation Quality
Deskphone (wired) Separate office voice network(s) just for phone devices Classic best approach for a dedicated business call center. Voice traffic is separated completely from data. What happens in the agent’s browser, in your web-based tools, in your data traffic all have zero impact on call reliability and stability. AAA
Deskphone (wired) Shared office network – phones and computers connected to same network Good quality for a small to medium call center – assuming very good quality network and preferential treatment of voice traffic where possible. For a call center that is not huge, you can get reasonably close to the AAA standard above, most of the time. AA
Softphone (on computer) Shared office network – Office with an optimized wired network shared by voice SIP devices and other data traffic Good quality for a small to medium call center – as above assuming high quality network optimized for voice. A
Browser phone Shared office network – all data and voice traffic shared in this case The good news is that it is possible now to achieve good quality on a browser phone (using webRTC). For convenience of setup and use, the browser-only approach is unbeatable. The downside is that for some network types and some machine/browser setups, more effort, monitoring and support is required.
Any issue with the browser or internet traffic in general will impact everything: latency, load times, real-time responsiveness, reliability and the audio quality. However, since many the processes agents do now are in any case heavily dependent on the browser anyway, the tradeoff can indeed often be completely acceptable.

Requirements for good call quality

Note that each device and network combination places some limit on the ability to optimize call quality. If for example you deploy in the AA category (deskphones connected to a shared office network), then it is appropriate to invest in certain types of network optimization, but you will quickly reach a point where you can only improve by changing your network setup to separated and dedicated for voice, i.e. to move to AAA quality category. To take another example, if you deploy in category B (browser phones), then even investing a lot in network optimization will not bring your achieved quality into category A and definitely not AA or AAA. However, as noted in above, the browser-only approach is now rather good quality and very convenient for agents and administrators.

The fundamental determinant of voice quality is how voice network traffic is handled – separation being the best form of preferential treatment. By way of background, consider the difference between calls and video streaming. Calls are two-way real-time interactions whereas video streaming can be buffered. On a call even a 70 millisecond delay can have a significant impact and at a little over one tenth of a second humans notice delays as barriers to communication.

Also even if your network is very fast, if you share with other data, it will have an impact on audio quality and delays some of the time. This is why call quality is so sensitive to the network and device setup. Note that for the browser phone scenario it can be even more critical to conduct the right network tests and to obtain sufficient knowledge and control of your own network and the way your ISP routes traffic.

We help businesses optimize their networks for voice all the time – it is our daily bread. Tackling the requirements for high quality voice head on is in our experience the only way to ensure that a business can operate a high quality call center. It is easy enough if you go about the network and device setup and selection in the right way.

This article is part of our series on networks and voice deployment.

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