When it comes to the quality of the connection, the focus is usually on the (maximum) speed and the eventual performance delivered compared to the speed advertised. Research has shown that fibre, and to a lesser extent cable, achieve speeds relatively close to those promised. ADSL and probably also VDSL have satisfied consumers less, as in practice the user receives around half the 'headline' speed advertised.
It's important to keep in mind that we are moving into a world where streaming services are increasingly important, and downloads play less of a role. For downloads, the connection can probably never be fast enough - people are simply impatient, as research by professor Andrew Odlyzko at the University of Minnesota shows. There is some sense then in striving for faster speeds. However, when it comes to streaming services, speed is only important up to a certain point. If an HD stream takes 15Mbps, then in theory a connection of around 15Mbps should be sufficient (taking into account overhead and packet loss). Overbooking also plays a role, as not all subscribers can stream (or download) content at the same time.
There is another parameter important for the quality of streaming services. It's less relevant for services that can build up a cache, but is critical for services requiring a short response time (latency) for a quality user experience. Examples include voice calls (such as Skype) and gaming. This is known as the 'capability' or 'stationarity' of the connection, as shown by consultant Martin Geddes.
His research shows that faster networks don't always score well on packet loss and delay, and in fact can even score badly on these parameters. This results in delays and gaps in a conversation. Only when both parameters are consistently low (a data packet loss of around 0.1 percent and a maximum latency of 50ms) does the user consider the quality as good.
In short, a gradual acceptance of the need to expand the measurement parameters for broadband quality is emerging. This means looking at not only the maximum speed, but also packet loss, latency and stability.
