Page 30 - EngineerIT September 2021

IN CONVERSATION

Satellites are dead! Long live satellites!

Hans van de Groenendaal in conversation with Dawie de Wet

ver the past decade, as the FTTX satellites (8 – 25 msec) and GEO satellites (550 msec, or just over half a second). To put
(fibre to everywhere) industry this in perspective, that’s approximately the time it takes for a person to say ‘hello’.
Otook off, articles in the media De Wet explained that outdated perceptions of latency have much more to do with
claimed that fibre is the death knell for people’s experiences of using less advanced computer applications which were not fully
satellites and that satellites are dead!. This compatible with satellite communication links. Computer technology has of course moved
perception could not be further from the on, and today’s PCs and laptop applications have no issues in receiving and transmitting
truth, as discovered in a conversation with voice, video and other data signals.
Dr Dawie de Wet, group CEO of Q-Kon. On
the contrary, satellites are alive and well, Smart satellite service
and on a growth path. Dr de Wet calls it a Current satellite services such as Twoobii, on the Intelsat Flex platform, are much more
gap between the market and the industry. advanced than previous generations. Smart satellite services have bust the myths that
“Revenue-wise, the satellite market is satellite is slow, expensive, and has a latency problem. Satellite platforms have evolved
smaller than networks on the ground but not and are today advanced IP connectivity solutions providing a real alternative for business
of less significance in the way it interacts and enterprise connectivity.
with our daily lives. One sees dishes on Smart satellite services include network architecture functions such as layer-2 options,
many garage forecourts. Satellites connect VLANs architectures, advanced quality-of-serve options, public IP number allocations,
many ATMs in the country and cities, and etc. It is these additional features that enable network architects to seamlessly integrate
if one looks at the number of launches satellite networks with end-user core networks, which are fundamental to unlocking the
for the next ten years, there are 332% business market for next-generation satellites.
more satellite launches planned than were
launched during the past ten years”. What is layer-2-over-satellite (L2oS)?
Satellite is certainly not dead. Perhaps Smart satellite services offer layer-3 as well as layer-2 connectivity options. De Wet
the satellite industry talks too little about explains that to understand the benefits of layer-2, we firstly need a basic definition of
its achievements, the development of layer-2 in IP networks.
new technology, overcoming latency According to Wikipedia, layer-2, also known as the data link layer, is the second level
issues and the mitigation of rain fade in the seven-layer OSI reference model for network protocol design. Layer-2 is the network
experienced on some of the satellite layer used to transfer data between adjacent network nodes in a wide area network, or
frequency bands. between nodes on the same local area network. Generally speaking, layer-2 is a broadcast
Latency refers to any delay in media access control (MAC) level network. Layer-3, however, is a segmented routing over
information transmission times for internet protocol (IP) network.
data – in this case, from the source to
the destination via an orbiting satellite.
Despite this, latency has traditionally been
used by proponents of other connectivity
technologies as a stick with which to
beat satellite internet services. “Latency
is a feature of all broadband networks,
including 5G and fibre. However, satellite
internet involves transmitting and receiving
signals over much longer distances.
These can be from 500km to 1500km,
in the case of low-earth orbit satellite
constellations (or 1 000 to 3 000km for
the ‘round trip’, which is the measurement
used for latency calculations).
Geostationary earth orbit (GEO)
satellites are positioned further from Earth,
and orbit at a distance of 35 786km. This
difference in height above the Earth’s
surface is reflected in the latency figures
achieved by low earth orbiting (LEO)

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