-Back to our common thread. This week, we will introduce

the terminal we have designed for this MOOC.

We have called this terminal the Maxibox.

It is designed with two elements.

The outdoor unit, made of the antenna, and the BUC and LNB pair.

Respectively the transmission and reception amplifiers,

with the conversions in the Ka and Ku bands.

Regarding the indoor unit, there is the Maxibox itself,

a hardened case which includes a 12-unit rack

to house the satellite modem among different elements.

The Maxibox is designed to operate with the satellite access.

However, it is absolutely possible to replace it

with another access technology.

This is illustrated on the left photo where we use a Wi-Fi access device

to catch an existing network.

It is now time to open this Maxibox and have a look inside.

Once the covers are removed, we can access the different devices.

Just a little side note.

You certainly noticed that this case is experimental.

A real professional would probably have done a cleaner integration.

On the left, from bottom to top, we can see the inverter

which filters the supplied power and potentially cleans it

if it is supplied by a power generator.

The inverter also includes a battery

allowing a backup supply of about 40 minutes.

This inverter is located below a drawer

used to store the fixed and wireless telephones.

On the upper rack, there is a NUC-type PC

which hosts the voice-over-IP calling server.

The latter is based on the free software Asterisk.

The PC also hosts a Web server for the local services.

A bit higher up the rack,

we can find the different communicating elements.

On the left, the DECT terminal for wireless phones

and its power over Ethernet.

This DECT terminal outputs voice-over-IP traffic

via the Ethernet plug.

On the right, on this same rack, there is a network device

combining several functions: switch, router and Wi-Fi access point.

The next photos show the case, its accessories and the back panel.

Regarding the back panel, excuse us as it is a recycled part.

There is a plug for the voice-over-IP fixed phone

and another for Internet access.

The satellite modem can thus be plugged here.

If you have trouble seeing all this, the two racks have been zoomed in.

Let us now see how all these devices

are interconnected from a network point of view.

As I told you, the central device combines layer-2 switch,

layer-3 router and Wi-Fi access point functions.

So it is in the middle of the illustration.

The system is made of three IP networks.

So they have different network addresses.

The first network, illustrated by the blue rectangle,

hosts the wired devices: voice-over-IP fixed phone,

DECT terminal, voice-over-IP calling server and user PCs.

The second network, a Wi-Fi network illustrated by the green rectangle,

hosts the wireless user PCs.

We have chosen to separate, from an IP point of view,

wired and wireless networks

in order to be able to protect them from each other if necessary.

With this in mind, the wired network can have more privileges

than the wireless network.

Finally, a third network, illustrated by the purple rectangle,

connects the modem to the central network device.

Within this system, some devices communicate and work together.

This is the case of the DECT terminal, the voice-over-IP fixed phone

and the voice-over-IP calling server.

On this illustration, we can see the different network functions

provided by the devices.

On the blue and green networks, we have the routing

which commutes packets between different IP networks,

the switching to commute packets within the same network,

and a DHCP server to distribute IP addresses

when the devices are plugged in.

The blue wired network adds a micro DNS server

to name devices such as the voice-over-IP server

or the fixed telephone.

Regarding the network connecting the central element and the modem,

there is also some routing,

but also what we call NAT or Network Address Translation.

This mechanism allows us to only show a single address outside

that happens to be the address

the modem provides to the central device.

Finally, to make sure that everyone shares the available resources

in an efficient way, we have installed quality of service policies, QoS,

to protect voice-over-IP in particular.

These policies imply packet marking

and throughput reservation at the output of the terminal.

Indeed, the uplink is generally more constrained than the downlink.

Here is the final link in the chain, the modem.

Here you can see two different models. This modem plays several roles

as we illustrated it during the other sequences.

These roles are clearly shown by the different connectors.

On the one hand, we have F-type RF plugs

to transmit and receive RF signals via a coaxial cable.

With other manufacturers there can be a single cable.

On the other hand, there is a RJ45 Ethernet-type network plug

to send and receive Internet traffic.

Based on the success of our Maxibox,

we wanted to push the concept a bit further.

Let me introduce you its progeny: the Minibox and the Microbox.

The Minibox is housed in a 4-unit rack.

It is more or less the Maxibox without DECT telephony

nor the inverter power management.

We have replaced the PC by an on-chip system,

a model called Odroid, to host the local Web services.

The Microbox is quite similar

but we have pushed integration a bit further,

it is still ongoing by the way, by using a hardened suitcase.

This time, in order to change and test different systems,

we chose the Raspberry Pi 2 on-chip system.

Minibox and Microbox provide the same services,

voice-over-IP telephony via the fixed telephone,

and wired and wireless Internet access.

Furthermore, both host a local Web server.

All these boxes aim at a nomad use.

In the setting of indoor Internet, it is much simpler.

The satellite modem will more or less play the same role as an ADSL box

if we had access to ADSL. In terms of material cost,

the Maxibox costs a bit less than 3 000 euros,

the Minibox a bit less than 500 euros

and the Microbox a bit less than 200 euros.

Of course, to this price we must add the price of the Internet access

no matter the technology used.

To conclude, we can say that the antenna and the satellite modem

are only the tip of the iceberg.

We must also take into account everything that will add value

to the Internet access service. This is precisely the role

of these different boxes we have introduced.

Internet by satellite

Introduction to Satellite Communications

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