Connectivity 101: How the Internet Works

In the not-so-distant past, boarding an airplane meant leaving the connected world—no cell signal, no internet, no connectivity to the ground. Over the last few years, however, airlines have invested in the technology to allow passengers to easily connect as they transition from the grounded world to the skies.

Extending the connectivity we enjoy on the ground to the in-flight experience is a natural evolution. Even so, the majority of people can’t explain how the internet works on a fundamental level, even as the number of internet users climbs past 5.35 billion. 

To understand how the internet works, let’s explore what it is at its core, the factors that affect performance, and what all this means for airlines.

How was the internet created?

In October 1969, researchers connected two machines—one at the University of California in Los Angeles and the other at Stanford Research Institute in Palo Alto— with 350 miles of leased telephone line. The goal was to transmit a simple message: “login.” UCLA was able to send both an “L” and “O” before the system crashed.

Just like that, the internet revolution began.

The network, dubbed ARPANET (Advanced Research Projects Agency Network), was the first computer network to use packet switching, a process where data is broken into small “packets” to expedite sending, then reassembled on the receiver’s end. It was also one of the first to use the Transport Control Protocol (TCP) and Internet Protocol (IP) suite, a set of rules and procedures about how data should be broken into packets, addressed, transmitted, routed, and received at the destination.

Today, both packet switching and TCP/IP form the technical foundation of the modern internet, a global network of computers that can transmit and receive data across all connected devices. Packets are forwarded using routers, a network device that acts as a traffic controller forwarding data to devices on different networks. Switches are used to connect devices that share the same network. An ability called multiplexing, where data from multiple sources is mixed into packets and combined for efficiency, then reorganized when they reach their destination, is also leveraged to improve efficiency.

What hardware is required for the internet?

Today, the internet has grown into a complex system of hardware, antennas, and satellites capable of connecting globally. Some of it is straightforward enough that even the most technologically unsavvy people can understand the basics. For instance, most people recognize that you need a device like a tablet, computer, or smartphone, plus a wired modem that connects your home to the internet supplied by your Internet Service Provider (ISP). Most devices are connected to the internet over Wi-Fi, short for wireless fidelity, an invisible, wireless signal that lets you check your email, stream on-demand video, and surf the web.

Other points on the connectivity path are less known.

Personal devices typically come with a network interface card, hardware which facilitates connection. A wireless access point (WAP) is a networking device that creates a wireless local area network (WLAN), which devices in the same area with wireless capabilities can connect to (like a laptop or tablet). Wi-Fi is a commonly used type of WLAN.

Airline-specific internet hardware

For airlines, achieving connectivity is more technical. Most modern aircraft have an antenna to communicate with the ground. Plane antennae also support in-flight connectivity through an Air-to-Ground (ATG) Wi-Fi network and Satellite connectivity.

With ATG, the aircraft is a hotspot, transmitting signals to and from cell towers on the ground using the antenna on the belly of the plane and redistributing the signals through several onboard WAPs. ATG’s reliance on cell towers makes it patchy for use while flying over large bodies of water or remote locations.

Satellite connectivity, on the other hand, uses satellites to allow airplanes to relay radio wave signals to ground stations and back up, allowing for better connection over oceans and remote places. Customers experience satellite connectivity by connecting their device to a Wi-Fi signal provided by a modem or router. That modem/router is itself connected to a satellite internet terminal, which connects to orbiting satellites. The signal then gets beamed back down to enable internet access.

Satellite internet is known for its low-latency , high-reliability connections. As a technology leader in the airline industry, Panasonic Avionics leverages a constellation of satellites in Low Earth Orbit (LEO) and Geostationary Equatorial Orbit (GEO)   to ensure continuous Wi-Fi coverage for its airline customers and their passengers. But creating a connection is just the start. Performance is also a key consideration.

What affects internet performance?

Whether used on the ground or in the sky, internet performance is the byproduct of a combination of variables.

When we talk about performance, we’re often talking about bandwidth, latency, and throughput. Let’s use water in a pipe as a metaphor:

-Bandwidth is the diameter (width) of the pipe. It determines how much water can move through the pipe.
-Latency is the time it takes for the water to enter and exit the pipe.
-Throughput is the rate of flow, how fast the water is moving through the pipe.

Speed is usually measured by the amount of data that can be downloaded or uploaded in one second, usually referenced as Mbps or Gbps, or megabits and gigabits per second. Meanwhile, the network’s physical infrastructure determines the capacity (bandwidth) of the network.

Beyond the type of connection, other variables affecting performance include: 

Devices have a dynamic effect on internet performance. An older laptop or smartphone could have outdated drivers or a network interface card that isn’t compatible with an ISP’s maximum supported bandwidth. Network modems, routers, and WAP can also underperform due to congestion from too many devices. The more devices on a network, the smaller the bandwidth, especially if the devices are attempting higher bandwidth activities like 4K streaming.

Walls and obstructions can block signals. Long distances from towers can reduce connection strength. Even interference from other Wi-Fi connections can cause your connection to underperform. Preserving signal integrity is a key consideration for airlines and the in-flight experience.

ISPs can impact performance and user experience. The ISP is responsible for dividing the bandwidth to meets user demands. To do this, the ISP uses tools like policy control and traffic shaping. Policy control refers to a series of tools to enhance the security of a network and ensure only authorized devices can connect, preventing unauthorized access, data breaches and other cybersecurity threats.

Traffic shaping and packet shaping is when ISPs regulate data traffic, blocking or prioritizing data delivery to ensure a consistent experience for users.

User behavior is also a critical element, because it defines internet traffic.

Traffic is constantly changing. Bursts of data are sent across networks and followed by pauses. Streaming takes place at varying speeds as data is buffered on devices and delivered. Emails are sent and read then replied to. Networks and ISP packages are designed using complex modelling of how many users and devices use the network and what they’re using it for.

All these variables bounce off each other and shape the internet as we experience it today.

The need for speed

It’s commonly assumed that the faster the signal is, the better. However, most of our internet activities as consumers don’t actually require breakneck speeds to deliver solid performance and a high-quality experience, in large part because of the human brain’s own limitations on latency, bandwidth, and throughput. Simply put, a delay of a fraction of a millisecond is imperceptible to us mere mortals.

At Panasonic Avionics, we’ve extensively studied connectivity trends. Based on our research  , we know that a WhatsApp text message only really needs a speed of a few Kbps, while listening to a song on Spotify or answering emails takes a speed of 1 Mbps. Streaming high-definition on-demand videos from YouTube or Netflix providers requires 1–5 Mbps to deliver a buffering-free experience, but ultra-HD streaming needs 15– 20 Mbps. Finally, uploading video to social platforms needs between 10– 25 Mbps.

As we can see, most activities don’t require the fastest, most powerful internet possible. Rather, it may be more advantageous to tap into a solid signal that can handle bursts of usage with ease. This provides a lot more flexibility when balancing customer expectations, costs, and capacity.