Page 8 - EngineerIT June July 2025

CONNECTIVITY

Speed tests and the missing Mbps:

why can’t you hit the 1Gpbs mark?

ong-time internet users may recall the good old days of dial-up internet The same applies to wireless
connections and the anticipation of a noticeable improvement in experience services, where, for example, even
Levery time the line speeds were upgraded. Fast forward to today, and though 5G may be capable of a
customers don’t seem to feel the same difference when upgrading – so, why is theoretical speed of 20Gbps, this is
that the case? This is where it becomes necessary to understand the differences based on using the best equipment
between capacity and throughput, and evolving connectivity requirements at in ideal conditions, and even then
home and the workplace. there are radio frequency limitations
that will prevent this speed from
A favourite thing for people to do when they get an internet connection for the being reached in real world use
first time, or upgrade, is to run a speed test. But, something strange happens: a cases.
customer with a 500 Mbps connection might download a file from a fast server
and achieve 480 Mbps; when they upgrade to 1 Gbps, they might expect to see ISPs also make use of contention,
960 Mbps, but instead, they only get 600 Mbps. which segregate different service
profiles. A dedicated service
External factors impacting performance will have much less contention
Why? At lower speeds, the internet connection itself is the bottleneck – meaning than a broadband service.
that you can get close to the plan's advertised speed. But, beyond certain speeds Higher-contended products
the bottleneck is no longer your access speed, but external factors such as allow customers to use their full
servers, end-to-end network conditions, and even the TCP/IP protocol itself. connection simultaneously, and
as such the customers share a
So, even if you have a 1Gbps, 10Gbps, or 100Gbps connection, if the maximum portion of the network's capacity. In
throughput achievable due to server-side or network limitations is 600Mbps, such instances, users may observe
that is all you will get. In this example, the capacity – the maximum data rate higher throughput at off-peak times,
under ideal conditions – is 1Gbps while the and lower throughput during peak
throughput – the actual data rate achieved times when more users are active.
in the real world – is 600Mbps. As fibre Similarly, with wireless services, the
internet access line capacities continue more people connect to a single
to increase, these limitations will become tower, the lower the throughput
more noticeable. becomes.

By Theo van Zyl (left), Head of Wireless at Vox, and Andre Eksteen (right)
Senior Product Manager of FTTB at Vox

8 | EngineerIT June/July 2025