Pingball

Perhaps you’ve wondered how an image, a song, an article or a video gets to your phone when you’re out and about. Yes, the phone somehow connects to one of the cell towers or antennas that are now attached to just about every roof and every pole. You pay your mobile carrier for that connection.

But what happens beyond that? How does the content get to the antenna? How does it get onto the carrier’s network? You know that Netflix, Spotify, Meta, YouTube and so on all have data centers storing content. You know that “cloud” is a thing—Perhaps you even deploy and run applications in the cloud!—but how does a video that lives in a cloud data center somewhere in the middle of the Oregon high desert end up on your phone in Oakland? How does it get there so fast?

Whether you are or aren’t a techy (maybe you are, but you’ve never needed to learn about this stuff), the infrastructure that makes these magical devices in our pockets go, its scale and complexity, the sheer number of moving parts all working in concert to make the magic happen—virtually without failure—are awe inspiring. Recently, we decided to dig into and learn about it ourselves, and then share what we learned with other curious minds out there, folks who could have wondered about these things but weren’t necessarily prepared to digest a handful of IEEE papers on 4G and 5G content delivery. The result is Pingball, a journey through the vast, endlessly fascinating physical infrastructure that’s become a vital organ of our entire civilization. We like how it came out and hope that you will too!

Creators

• Aleksey Bochkovsky, Dandelion Air (concept, cinematography) 
• Alex Tomilov (design, animation)
• Arthur Muradyan (art director)
• Katie Norchi, Equinix (narration)
• Oleg Berzin, Equinix (technical advisor) 
• Yevgeniy Sverdlik, Equinix (writer, producer) 

Transcript of the Narration

This video will follow an internet signal—or Ping—on its journey through a vast physical infrastructure designed to get us our digital content in an instant. 

The first leg of Ping's journey lies through air. It travels from the tiny antenna inside your phone to the nearest cell site in the form of radio waves. 

In this case, the cell site is a tower, but it could also be on the roof of a building, a utility pole, or some other raised structure. One of the antennas on the tower picks up the radio signal and converts it to electric current, which then goes down to “eNodeB.” 

eNodeB—or in 5G networks, gNodeB—is the brain of the cell site. It transmits information via the antenna, interprets the electrical signals coming from it, directs traffic along the network, and does a bunch of other things to manage the radio network. 

eNodeB sends Ping further along the carrier’s backhaul network. “Backhaul” is jargon for long stretches of high-bandwidth, high-capacity fiber cables underground that carry bits and bytes over long distances. Our Ping, along with data from all the other people’s mobile devices that are close to that tower gets “backhauled” to the carrier’s “core network.” 

A carrier‘s core network usually lives in a building filled with networking equipment and servers, in other words, a data center. 

A building like this aggregates network traffic that travels to it over a mobile backhaul network from all cell sites within a certain radius. All the things done by the equipment inside are collectively referred to as Mobile Packet Core. They enable both 4G and 5G networks. 

Mobile Packet Core functions run on typical computer servers you’d find in a cloud data center. The main ones are routing traffic as it enters the building from the tower side or back toward the towers, authenticating subscribers, setting up calls, and handing traffic off to an Internet Service Provider, or ISP. It’s the same kind of ISP that gives you internet access at home. 

Ping gets handed to an ISP and we can now safely say that it is officially on the internet. Its next stop is another data center, but of a different kind. 

They say the internet is a network of networks. Instead of hosting a single carrier’s network gear this next data center is home to many networks, which are there to meet and interconnect with each other. They could be cloud companies, content companies, ISPs, large banks or insurance companies—anybody that needs to connect their network to someone else’s network. These facilities are the nerve centers where the smaller networks interconnect to form the larger network—the network of networks. Most Internet Service Providers keep their core network equipment in data centers like these. 

Once in the building, Ping travels to the networking equipment of the ISP responsible for retrieving the user's content. The next most likely destination from there is the Internet Exchange. Its switches and routers are in the same facility. 

Internet Exchanges enable peering, which is when two networks agree to interconnect and exchange traffic, essentially treating each other as extensions of themselves. It’s where they can connect to other ISPs and, really, the rest of the internet. It’s how they get video from YouTube, Netflix, Twitch, or any other content their customers want to see onto their networks. 

Through the IX, Ping gets onto a Content Delivery Network, or CDN. 

As the name suggests, CDNs deliver content to end users. They store content copies in many locations so that it can be accessed locally instead of traveling over long distances. Everybody from streaming services to cloud platforms uses CDNs. Some companies have their own CDNs and some use third-party CDN providers. 

The request has now reached the CDN server where a copy of the video Ping wants to get is stored. The server receives the request and starts sending data packets containing the video back down the same path, to the IX, to the ISP’s equipment, to the carrier’s core network, through the backhaul network in the ground to the eNodeB box at the tower, to the antenna, and finally, through air, to the user’s phone.