Block I Illinois Library Illinois Open Publishing Network

Rainbow Unit: Networks Big and Small

2B: The Infrastructure of the Internet

Technical Overview

Seven layers of the OSI Model: 1. Physical: Copper & fiber cables, radio frequency & infrared wireless. 2. Data link: Media Access Control (MAC). 3. Network: Routing of data packets. 4. Transport: End-to-end connections. 5. Session: Interhost communication. 6. Presentation: Data translation & representation. 7. Application: What the 'end user' sees.
A visualization of the seven conceptual layers of the Open Systems Interconnection (OSI) model.

The hardware infrastructure of the Internet happens at layers 1 and 2 of the OSI model. Layer 1 provides the cable and radio wave that interconnect devices, along with the installed within the computing device to which media connects. When formally connected to an network the NIC becomes a on the network. Layer two of the OSI model provides the identification mechanisms for the node. A computing device can have one or more than one NIC. For instance, your laptop may be simultaneously connected to a network with both a wired Ethernet media & NIC and a Wi-Fi media and NIC, and your smartphone to a cell radio wave media and NIC and also a Wi-Fi media and NIC. Each NIC is uniquely identifiable so that information is correctly disseminated to the appropriate device. To direct the flow of information between nodes, there must be an or a combination of devices to facilitate communications. The only exception is when two nodes use the NIC, node identifiers, and media to do direct peer-to-peer communications.

Computer Network Building Blocks

There are four main components needed for a computer or other computing device to join as a node on a local area network (LAN) within a building such as a home, library, office, or cafe.

Node Identifier

Any device directly connected to the network that has been assigned a unique identifier on that network. Examples include:

  • MAC address (also known as the hardware, physical, or Ethernet address): The serial number for Ethernet cards.
  • IP address: The address used by the Internet protocol.

Network Interface controller (NIC)

The hardware necessary for a node to connect to a network. Examples include:

  • Ethernet controller (wired Cat5/Cat6 or wireless/Wi-Fi): Used for LANs.
  • MODEM (cable, DSL, dialup): Used for traditional internetworking with the Internet.
  • Optical Network Terminal (ONT): Used for fiber to the home Internet.


The communications technology used to connect nodes. Examples include:

  • Copper transmits low-voltage electricity (e.g., wired Ethernet, DSL, cable, dialup).
  • Fiber optic transmits light (e.g., fiber to the home).
  • Radio waves (e.g., wireless Ethernet or Bluetooth).

Interconnect Device

A device used to interconnect nodes. Examples include:

  • Switch or hub: Wired Ethernet LAN.
  • Access point: Wireless Ethernet (Wi-Fi) LAN.
  • Router or gateway: Builds an Internet by connecting different LANs together.
  • Hotspot:
    1. A popular alternative term to access point on a Wi-Fi LAN; or
    2. A mobile device (e.g. Smartphone, Coolpad Surf, NetStick USB Modem, or MiFi 8000) that is both a cell-based wireless router and a Wi-Fi access point providing Internet access through the cell-based Internet connection.[1]

Nodes interconnect with other nodes in different ways, depending on how far they reach geographically, how many people are meant to use them, and who primarily owns or controls them. Some cover a very small area and may be used for very specific devices, while others are more general, cover larger areas, and are especially effective for use on the Internet.

Network Areas of Coverage

  • Personal Area Networks (PAN) provide a simple computer network organized around a few personal devices, allowing the transfer of files, photos, and music without the use of the Internet or your home’s local network. Two common examples would be your Bluetooth headset or keyboard and mouse. Depending on the Bluetooth range selected (or chosen for you), this could span three feet, ten feet, or one hundred feet. Beyond Bluetooth, other common PAN connectivities include Infrared (IR), USB, ZigBee, Wi-Fi, and radio frequency (RF, including short-distance AM and FM radio).
  • The simplest type of Internet-based area network is a Local Area Network (LAN). A LAN is a network with connected devices in a close geographical range. It is generally owned, managed, and used by people in a building. For example, connecting to a Wi-Fi network at a coffee shop or library would mean that your device would be a node on the café or library’s publicly accessible LAN. Many public spaces may have a second, private LAN for use by staff only.
  • A Wireless LAN (WLAN) is another name for a LAN used over Wi-Fi. In some cases, a router is used to strategically isolate the wired Ethernet LAN from the wireless Ethernet LAN and may therefore distinguish between the networks specifically using LAN versus WLAN connectivity.
  • A Metropolitan Area Network (MAN) is a collection of LANs and devices in an area the size of a city. A version of a MAN is a Campus Area Network (CAN), which would be a network the size of a college, organization, or business campus. These types of networks are typically community-owned and/or managed, and may also provide the infrastructure for one or more local/regional Community Networks.
  • A Wide Area Network (WAN) covers the size of a state, country, hemisphere, or globe. A WAN is comprised of multiple MANs and/or LANs interconnected through a backbone or core transmission line or set of lines. The primary WAN we know of today is the Internet, a federation of local and regional networks interconnected through transmission lines typically owned and managed by one or more Internet service providers (ISP: the business that provides connections to each LAN), network service providers (NSPs: the business(es) that provide connections between ISPs), and backbone providers (the business(es) that provide the more extended connections between NSPs).

The backbone of the Internet, that part serviced by network service providers and backbone providers, is constructed using a cable infrastructure. To carry signals rather than using electrical signals, glass fibers are used to carry light, with upwards of a thousand fibers being located within a single cable cladding. It is often the case that more fibers are included within a cable than are needed at the time of installation (called dark fiber) to allow for future growth without additional installation expense. Further, Wave Division Multiplexing (WDM) is used to allow multiple different wavelengths of light to be distributed on each strand of fiber (multiplexed) and then later separated (de-multiplexed), transmitting multiple communication streams simultaneously though a single light pulse. As technology continues to improve, replacement of multiplexers for newer models is allowing for still further data to be transferred over existing lines without additional installation expense of the cables themselves. The data itself is transferred using pulses of light transmitted using light-emitting diodes (LEDs) or small lasers. This can be done at very high speeds and over very long distances with less susceptibility to interference. A few different techniques are used to separate different wavelengths of light in ways that allow multiple communication streams, each at high frequencies, supporting higher capacity in addition to high frequencies. This opens up data transfer rates using fiber optics that are 20 to 1,000 times faster than copper cable and outdoor Wi-Fi Internet service and for a larger customer base. As Susan Crawford points out in her 2018 book, Fiber: The coming tech revolution—and why America might miss it, “If the information-carrying capacity of copper wire is like a two-inch-wide pipe, fiber optic is like a river fifteen miles wide.”[2]

Within the United States, most Internet service providers, on the other hand, make use of existing communication technologies developed for phone and cable television to also provide Internet access. Indeed, it has often been marketed as the “triple play,” a discounted package providing these three at a discounted price compared to the purchase of each one individually from the provider, or from several different providers. In some cases, a provider primarily uses one technology, such as the cable Internet used by Xfinity/Comcast. On the other hand, depending on your geographic location, you can get Internet service from AT&T via copper digital subscriber line (DSL) or fiber optics Internet lines, as well as via radio waves through their wireless phone services.

Internet Service Provider Technologies

Digital Subscriber Line (DSL)

  • Adds two channels to standard phone line for Internet
  • Hub and spoke (dedicated line) topology; full duplex
  • In the U.S., DSL prioritizes download speeds

Cable Internet

  • Redirects a cable channel to be used for Internet
  • Neighborhood shares bus topology; full duplex
  • In the U.S., cable internet prioritizes download speeds

Cell-Based Internet

  • 3G adds the EV-DO (Verizon, Sprint/Nextel) or HSDPA (AT&T, T-Mobile) protocol to cell voice’s protocol
  • 4G adds the WiMax (Sprint) or LTE (Verizon, AT&T) standard to cell’s voice protocol
  • 5G is based on previous-generation cellular principles that use current low-band wireless frequencies with slower speed but longer distances[3]
    • 5G-NR (New Radio) can incorporate mid-band and millimeter wave (mmWave) high-band frequency bands.
    • mmWave provides the highest speeds but with a much shorter distance range, while mid-band balances data transfer speeds and distance covered.
    • 5G is capable of transferring data at ten to one hundred times the speed of 4G within these new radio frequencies; Non-Standalone (NSA) 5G allows for the combination of 4G infrastructure for voice communications and mmWave frequencies for increased data capacity
    • 5G upload speeds remain generally slower than download speeds, but have improved significantly over 4G, especially within the mmWave band being directed towards Internet of Things (IoT) applications.
    • Actual performance can vary significantly, as some packages provided by 5G providers for businesses will differ significantly from those provided to the general public, and information on availability and for whom can prove difficult to find.
  • Equivalent to bus (shared) topology as radio signals can overlap; half duplex
  • Applications of cellular services generally prioritize download speeds

Satellite Internet

  • Indoor Unit (IDU) provides a modem connecting premises router to antenna dish (outdoor unit, or ODU).
  • The very-small-aperture terminal (VSAT) dish antenna, which can also be used for satellite television service, requires a clear line of sight to facilitate microwave communications directly with the geostationary satellite serving the Internet provider, or to a shared Gateway Earth Station (gateway hub) that then connects to the satellite.
  • Broadband speeds have improved considerably, with download speeds now reaching up to 40 Mbps. Download speeds are prioritized over upload speeds.
  • Latency of signal, the delay between end node data transfers, is typically over 500 milliseconds. Wired Ethernet on a LAN is typically below 2 milliseconds; regional copper Internet latency is typically below 10 milliseconds. Latencies above 100 milliseconds can be problematic for some Internet applications, such as live stream conferencing and online gaming.

Community Wireless

  • Uses standard wireless Ethernet (Wi-Fi) outdoors; anyone can use off-the-shelf equipment to create
  • Equivalent to bus (shared) topology; typically half duplex
  • Synchronous upload and download speeds

Fiber Optics

  • Ultra-high-speed communications technology with one or more channels for Internet
  • Hub and spoke (dedicated) topology; full duplex
  • Synchronous upload and download speeds, ultra-low latencies

For most homes, community organizations, and small office/home office contexts, a gateway is used that provides a WAN port used to connect the media leading to the first router of the Internet service provider. While sometimes this WAN port may need to first connect to a DSL/Cable or a fiber optics Optical Network Terminal (ONT), in other cases, this interconnect device is integrated into the router. Typically, a gateway router will also incorporate both wired Ethernet switch and Wi-Fi access point interconnect devices for interconnectivity on the LAN side of the router. In addition, a gateway router typically integrates a server that dynamically or statically assigns IP addresses to connected nodes on the LAN. The router will be configured to route essential Internet “phone book” type lookups to a designated ISP or third-party server that contains a database of public and associated IP names. All of these additional services facilitate its core function as the router between the LAN and the WAN.

We’ve worked through quite a few underlying concepts related to computer networks. Before moving into our first exercise, take a few minutes to review what we’ve already covered and also to get a glimpse at materials we’ll be covering next by watching Carrie Anne Philbin’s introduction to Computer Networks, Crash Course Computer Science episode #28:

Exercise: Listing Building Blocks of Your Computing Devices

Before moving on further, take some time to look at your own Local Area Network (LAN), whether it’s the one in your place of residence, the LAN of a family or friend, or that of your workplace, library, community center, etc. To the extent possible, do this at a physical location where you can see the various network building blocks, and maybe do it with the person who took the lead in setting things up if you weren’t the one who did that.

An Excel document with six columns. Headers from left to right: Location, Note 1, Note 2, Note 3, Note 4, Note 5. Rows in the location column list networking terms, such as Internet Service Provider, Gateway Router, etc.
A Local Area Network (LAN) documentation template.

Download the Excel spreadsheet template.

  1. Begin with the information regarding the Internet Service Provider connecting the premises to the Internet. What type of communication technology and media is used to connect the premises to the Internet? What are the specified upload and download speeds for the service being provided? Are there any monthly data caps limiting use? As other things come to mind, also include notes on this information.
  2. Next, explore the gateway router that provides the first hop between the WAN and the LAN you are documenting. To the extent possible, document the MAC and IP addresses of the router’s WAN Network Interface Controller, and also that of the router’s LAN NIC (remember, many devices have multiple network interface controllers, and therefore multiple node identifiers). Are there additional devices between the outdoor media and the router, such as a modem or optical network terminal? Does the router provide one or more LAN ports? Does it serve as a wireless access point? What are the settings for these? Does it provide a DHCP server giving IP addresses to other LAN nodes, and if so, what are the settings for this service? Are any IP addresses reserved for specific devices? Does it forward port requests that come to its WAN IP address to specific LAN node IP addresses? Are there any security access controls, block sites, and block services being used?
  3. Finally, do all you can to document every node connected on this LAN, noting the type of device, the media being used, the assigned MAC and IP address, and any notes you think would be helpful to keep on record. Remember to that your laptop, printer, Raspberry Pi, and other devices might be connected through multiple means such as via WiFi and also wired Ethernet. You might also document devices that are connected to multiple different networks, for instance a smartphone that is connected to the LAN using WiFi and also to a cell network. And there may be devices like that smartphone that also serve as hotspot routers, connecting some devices to the Internet via the cell network instead of the LAN’s ISP.

Key Takeaways

This exercise synthesizes concepts integral to computer and network building blocks. It also demonstrates an important principle regarding documentation. It’s easy to forget some of this information until computer network trouble is encountered. Filling out this form and occasionally updating it before again tucking it away in an easy-to-access file folder can prove of significant value when troubleshooting an array of computer network issues.

Also, it is sometimes helpful to have these notes on hand and add to them strategically in combination with the Network Troubleshooting chapter.

More on IP Addresses and IP Names

When we type in a URL, or Uniform Resource Locator, in a web browser, we’re almost always typing in an Internet Protocol name. Consider for instance the URL to this book:

Hypertext Transfer Protocol (HTTP) is the ever-present client-server protocol we have used for the last several decades to move information across the Internet. In this case, the first part, https, indicates the resource we’re searching for is the secured HTTP protocol (HTTPS). The second part indicates the providing resource is the web server with name The last two parts indicate the directory and subdirectory in which the specific resources being requested are located. Not specified is the specific file, which in this case probably defaults to index.html, index.php, or something similar.

But as with our phone system, the name doesn’t truly get you in. Rather, the IP name needs to be associated with an IP address to pull up a web page, just as a person’s or organization’s name needs to be associated with a phone number to make a phone call. As of this writing, to get to the website, is actually first converted to the IP address in order to access the server. We can do this ourselves by typing in:

Only IP names are converted to IP addresses. The directory and subdirectory listings use whatever characters were used to create those directories.

The Formation of IP Domain Names

The basic structure of the Internet came out of research launched in 1973 through funding from the U.S. Defense Advanced Research Projects Agency (DARPA). Researchers developed came a system of protocols known as the Transmission Control Protocol (TCP) and Internet Protocol (IP), or TCP/IP Protocol Suite.

In 1983, a conceptual framework for domain names was established through the RFC, in order to support the growing number of applications spanning multiple hosts, networks, and finally the Internet.[4] RFCs 883 and 973 expanded the domain name system (DNS) to build an intentionally extensible system. In 1987, two new RFCs made 882, 883, and 884 obsolete. These were “Domain Names – Concepts and Facilities, Request for Comments 1034” and Domain Names – Implementation and Specifications Request for Comments 1035.

These, too, have since had a range of RFC updates related to specific components of DNS:  1101, 1183, 1348, 1876, 1982, 2065, 2181, 2308, 2535, 4033, 4034, 4035, 4343, 4035, 4592, 5936, 8020, 8482.

Design Goals of DNS

The primary design goal of the domain name system (DNS) “is a consistent name space which will be used for referring to resources. In order to avoid the problems caused by ad hoc encodings, names should not be required to contain network identifiers, addresses, routes, or similar information as part of the name.”[5]

Today, we have a range of top-level domains, some of which are based on organization type (e.g., .gov, .edu), geographic location (e.g., .uk, .es), or general category (e.g., .org, .com, .net, .site).

Individuals and organizations can apply for second-level domains they can then use on the Internet (e.g.,,,,

Individuals and organizations can then create subdomains to extend their DNS tree to represent sub-groupings (e.g.,,,

Fortunately, another thing the RFCs for domain names came up with was a solution to the pesky phone system.

Consider that to call someone with our phone we need to know a series of numbers in order to dial them, employ our smartphone’s contacts app, or create our own name/phone number listing system that informally maps a name we can remember to that series of numbers we need to dial.

By contrast, all IP names that are to be accessible need to be formally mapped within a DNS server. Each registered second-level domain runs its own local DNS server that holds the authoritative mappings. Top-level domain providers then run DNS servers that map the second-level domains, like, with the authoritative DNS servers for that domain. Internet service providers also run DNS servers that can be used to temporarily remember mappings for a set period of time, generally as defined by the second-level authoritative DNS servers. These are used by our local area networks so that we only have to type in in our web browser, and not

IP Addresses

Internet Protocol addresses are the formal identifier of a node on a TCP/IP network. These addresses are used to route messages between source and destination across a network. Introduced in 1983, IP version 4 addresses use a 32-bit number broken into four 8-bit numbers separated by periods. When working in 8-bit binary notation, the decimal equivalent ranges between zero and 255. That is, an IPv4 IP address can range from to Protocols and policies have been developed to provide clear guidance regarding these addresses.

Almost all IP addresses, ones such as, are publicly accessible over the Internet. While some are not formally mapped to domain names widely known across the Internet, and some have strong security measures to restrict access, these numbers all can work across the Internet as needed/desired. For this reason, any router that is publicly available over the Internet (linking a Local Area Network to Wide Area Networks) must have one of these public IP addresses. The router you use at your home, office, or other organization to connect to the Internet through an Internet Service Provider is typically assigned one of these public IP addresses. Often, it’s only given to you temporarily, and may change dynamically in structured or semi-structured ways. But for those needing to ensure reliable access to nodes, for instance to web or database servers, you might purchase a static IP address so that you can set up routing information in a DNS server.

In the late 1990s, the Internet began running into the limits of IP addresses in version 4. As a 32-bit number, the maximum number of addresses available was 4,294,967,294. While that seems like a lot, given an increasing number of people have several different Internet “smart” devices in addition to their own laptop, four billion addresses isn’t nearly enough. These protocols were given out in formal ways that suited the 1970s’ and 1980s’ understanding of the limited uses of the Internet—a far cry from what really evolved. IPv6 was ratified in 2017 but has yet to be fully implemented. It uses 128-bit, allowing 3.4×1038 possible addresses.

Private IP Addresses

In creating the Internet Protocol, there were several blocks of IP addresses that were made private. Anyone can have access to any of these without any required registration of them. The only caveat is that they are meant for use on private networks and cannot be routed through the public Internet.

The Internet Engineering Task Force (IETF) directed the Internet Assigned Numbers Authority (IANA) to reserve the following Internet Protocol Version 4 (IPv4) address ranges for use on private networks:

IP address range Maximum number of addresses available to a single Local Area Network – 16, 777, 216 – 1, 048, 576 – 65, 546

Private IPv4 addresses are widely used today. They allow a home or organization to create personal private networks for internal use and then set up routers to translate traffic (NAT, or Network Address Translation) meant to pass between that private network and the public Internet. Or more likely, when you purchased Internet access through an Internet Service Provider, the router they purchased came set up with a Dynamic Host Configuration Protocol (DHCP) server. This router hands out private IP addresses to nodes like your laptops, desktops, phones, and printers, or to those connecting to the router via WiFi. That router also is a NAT doing the network address translation to its Wide Area Network public IP address assigned to it by that Internet Service Provider.

Take a few minutes to join Carrie Anne Philbin in this introduction to the Internet, from Crash Course Computer Science episode #29:

Exercise: Internet Detective

When the Internet is working at expected levels, we generally don’t think about the extensive collection of sociotechnical artifacts needed for one node to communicate with another node on a local network, let alone the many more that allow us to connect when the end-points cross the globe. When things are less than optimal, our responses vary from stepping out for coffee in passive acceptance, to pangs of guilt that we must be doing something wrong, to anger that nothing can be done when essential services are being lost.

This exercise equips us with sleuthing tools as we work to demystify the Internet further.

A networking flowchart: Domain Name System (DNS) is connected by the dig and whois Unix commands to the Network Interface Card (NIC). The NIC is connected via linklights to a network switch, by the ping command to another NIC, and by a router (an interconnect device for TCP/IP) to other routers, switches, and NICs. These other routers, wireless access points, and switches, which are all interconnect devices for Ethernet, are connected via the traceroute Unix command, which identifies each intermediate router, or 'hop.'
A network flowchart highlighting connection points at which different troubleshooting techniques apply.

As explored in the extension chapter on Network Troubleshooting, there is a range of network troubleshooting tools such as ping, traceroute, and speedtest. And there are a couple of tools that are especially helpful when sleuthing IP names: whois and dig. These tools are often installed or available to be installed on different operating systems. They are also integrated into various webpage tool sets.

Before beginning, we must update and upgrade the Raspberry Pi operating system. This is necessary for The General Purpose Raspberry Pi Web Server exercise later, so let’s get a head start. At the same time, we can install whois and dig in the operating system. The advantage to this is ensures the following exercises are completed in a consistent manner.

Enter these commands to update the Raspberry Pi and install the following packages. Note that each of these commands start with the word “sudo.” This indicates the command that follows (such as apt) is issued as a superuser: a user with administrative privileges. As you go, you may periodically be required to enter “y” for yes, or hit “q” after reading upgrade information, before you can proceed with the upgrade.

pi@raspberrypi:~ $ sudo apt update

pi@raspberrypi:~ $ sudo apt upgrade

pi@raspberrypi:~ $ sudo apt install dnsutils

pi@raspberrypi:~ $ sudo apt install whois

Take a few minutes to test the strategies for tracking down problems and identifying if there’s something we might do about them in Network Troubleshooting. Take a close look especially at traceroute. What can the following tools tell you about a network?

  • link lights
  • ifconfig/ipconfig
  • ping
  • traceroute
  • speedtest

Let’s do a quick initial exploration with the traceroute command to see where the website might be located physically:

pi@raspberrypi:~ $ traceroute

For those running the traceroute command in a Windows PowerShell terminal, you’ll type in tracert instead.

In PowerShell, the command traceroute is run. Below, the command shows the hops and IP addresses of each hop.

I see a first hop that takes me to my gateway router on my LAN, and then the first router of my ISP. A few lines down, I see I’ve reached A quick search on my web browser, typing in in the search bar, takes me to NTT Communications, a Global IP network. In my search, it actually defaulted to Japanese which I had my browser translate, indicating this is likely a Japanese-owned corporation providing backbone service in the United States. The 5th hop also includes “” within the IP name, which suggests the router is probably in Chicago, Illinois, United States. This would make sense as I live and am doing this traceroute just a couple hours south in Champaign, Illinois. Hop seven takes me to an IP address that includes the name “cloudflare” before finally reaching, the IP address associated with the IP name as listed at the top of the traceroute.

One thing that isn’t fully clear is the details regarding the second hop of the traceroute, the one that leaves my premises and takes the packets of data to my ISP. This is a place where the ‘dig’ command can sometimes prove very helpful. Before moving on to explore the use of that command, here’s a snapshot of a search I did indicating that second hop was to, the leaser of the fiber optics municipal area backbone network owned by the cities of Champaign and Urbana in collaboration with the University of Illinois Urbana-Champaign.

In the Microsoft Windows 10 PowerShell, with an active console connection to the Raspberry Pi, the command traceroute is run. Within the result, the IP address is highlighted. Below, the command dig -x is run. Within the results, under Authority Section, the text is highlighted.

Once installation for dnsutils (which include the dig command) and whois is complete, proceed. Let’s learn more about the dig command, starting with a search of the manual command within Linux before moving on to do a couple of searches specific to the IP name and IP address.

From the Raspberry Pi command line, type:

pi@raspberrypi:~ $ man dig

Dig (domain information groper) performs Domain Name System (DNS) lookups. It’s a flexible tool which can take some time to understand fully. After skimming through the manual entry, let’s do a couple of quick tests of the command.

pi@raspberrypi:~ $ dig

Here, we see within the “QUESTION SECTION” that we’re looking for type ‘A’ information. In DNS, ‘A’ records store the 32-bit IPv4 address(es) associated with a hostname. Here, we see the IP name actually has been assigned two, and

In a web browser, type in first one, then the other, of these IP addresses. What do you get as a webpage? What does this tell you?

Let’s do a reverse lookup to get the ‘PTR’, a pointer from an IP address to the associated canonical name.

pi@raspberrypi:~ $ dig -x

Here we see in the “AUTHORITY SECTION” that ARPA provided ‘SOA’, that is, the start of a zone of authority record, in which this IP address is associated with, the authoritative Domain Name Server for According to their “About” page, Cloudflare is a “service that protects websites from all manner of attacks, while simultaneously optimizing performance.”[6] While we don’t know specifically how, we do know that Adafruit Industry is associated with, or makes use of in some way, Cloudflare.

Let’s now use the whois command to see if we can learn more about Adafruit and Cloudflare. From the command line, type:

pi@raspberrypi:~ $ whois | less

(NOTE: the pipe symbol, found on the upper right between the “enter” and “backspace” keys on US keyboards, takes the output from one command and passes it to the next command, in the case “less” which allows us to view the contents one page at a time, moving back and forth within the text.)

Here, we see that the domain “” is registered through NameCheap, Inc. The name was created in May 2005, was last updated July 2018, and will expire May 2026 — IP names are not owned, but only leased.

We then find that the Domain Name Server for the domain name “” is hosted by Adafruit, Inc. may still host the website in-house, or may use another service to do the hosting using an Infrastructure-as-a-Service or Platform-as-a-Service “cloud” web server. From this, the only thing we do know is that Cloudflare is performing as a Domain Name Server for Adafruit. The DNS system actually has quite a range of record types that can be effectively used to support a wide mix of IaaS, PaaS, and in-house infrastructures simultaneously in support of one domain name. As a result, can actually be making use of a number of different in-house and remote-located services.

Use the up and down arrows to explore further the Registrant, Admin, Tech, and Name Server information records for the domain name. Then let’s do the same for by typing:

pi@raspberrypi:~ $ whois | less

We do see some information regarding creation, updated, and expiry dates, and also the Name Sever for the domain. But we also see that while early in the establishment of the Internet Protocol all records were kept open, today many items can be held private from the public. So we see far less in whois for Cloudflare than we did for Adafruit.

Before moving on, let’s take a quick look at the whois manual:

pi@raspberrypi:~ $ man whois

This description specifies this application searches for an object in the Request for Comments (RFC) 3912 database. Towards the bottom of the manual, NOTES are listed clarifying the search process and some of the underlying official resources searched depending on context.

Key Takeaways

The tools traceroute, dig, and whois can provide us with a considerable amount of information regarding the Internet backbone and the different end-point entitities that comprise the social and technical infrastructures that for the most part we just think of as a website. From the LAN of the personal computer running the web browser to the LAN of the computer or system of computers running the web server, there is an array of other LANs running the Domain Name Systems used to go from IP names to IP addresses, and then to specific server LAN locations that may vary depending on personal computer LAN geographic location, and then to various performance and security services, such as that from Cloudflare, that are used to further advance performance, and the many other systems and services hosted on still other LANs, only some of which are using HTTP web services. This Internet web, something that happens out of sight and mind, transfers untold packets of data around the globe every millisecond, coming back to our personal electronic devices as web pages, email, and audio/video communications in what appears to be a single, consolidated information artifact. What we don’t see is the wealth of sociotechnical artifacts all influencing the shaping of this single information artifact we have received or transmitted.

Take a few minutes to check out Warriors of the Net. You can see a unique visualization of packets, routers, and even a guest appearance of the Ping of Death.

Digging Deeper

From Adafruit to Raspberry Pi: We used several tools to explore the hops to, the IP address of Adafruit, the registrar used to lease the IP name and the Domain Name Server used to associate the IP name with an IP address, and other bits and bobs about the provider of core parts of the toolkit used for hands-on exercises in this textbook. Consider repeating this now to explore further How does this compare and contrast with the exploration? Is there anything new that you learn from this parallel exploration?

The Author’s Site: You can find my blog,, a subdomain under my leased domain name This domain name is hosted by an Infrastructure-as-a-Service (IaaS) provider, Dreamhost. As the iSchool was winding down Prairienet as a regional community network web-hosting service in the early 2000s, we searched for alternative web-hosting services for our non-profit patrons. Dreamhost not only provided web hosting, they also provided domain name registration, both at no cost for 501(c)(3) non-profits. As we helped move many non-profits to Dreamhost, I also moved my own website there and pay a yearly fee so that I can continue leasing the domain name and also provide a WordPress service for subdomain I have a second website,, that currently redirects to the IOPN home for this book. In the coming years I may again deactivate this redirect and reactivate Dreamhost hosting of a WordPress site and using a PressBooks theme to allow testing of new chapter sections for a 3rd edition if I so choose. What can you learn about these two subdomain websites and the IaaS through the use of traceroute, dig, and whois in addition to the things you can learn by using a web browser to go to these sites?

São Tomé é Príncipe, Africa: I’ve valued my time doing participatory action research community inquiry projects in São Tomé é Príncipe, Africa, with citizens of this island nation, to advance their community cultural valued beings and doings. We found it technically impossible to set up community wireless on the island because of volcanic deposits that significantly interrupted Wi-Fi signals. We also found a nation that valued analog interactions within the marketplace and that made use of the public and community radio stations available. And their ISP provided wired broadband that valued upload speeds over download speeds so as to bring forward the information of people to others instead of focusing only on centralized corporate information sources being brought down to the people. But to bring this all to a broader audience, the official website of the nation is not located on the island. Where is it located? Who oversees this website?

To do this last Internet detective dig, consider the different top-level domains that might be used in association with this nation. Within the United States, where the Internet was birthed from ARPANET, we would use the “.gov” top-level domain name for a government, and “.edu” top-level domain name for an educational institution. But other nations needed to either apply to the United States for second-level domains associated with a top-level domain (which they couldn’t do for .gov but could do for .com), or they needed to use their national top-level domain first (e.g., specifies a .com site within the United Kingdom). For this detective task, try out different subdomains, such as (the site listed within the Wikipedia listing for São Tomé),, and Which are trusted sources of information about the nation, if any? Who hosts these websites? Who manages them? What is left unknown through the use of these tools?

Cloud Computing

When discussing Internet-based applications today, the term cloud or cloud computing is often used. Indeed, sometimes the word cloud is used synonymously with the word Internet. Cloud computing, like the Internet of Things, is an evolving paradigm. For this reason, in 2011 the National Institute for Standards and Technology, as part of its statutory responsibilities under the Federal Information Security Management Act of 2002, developed a short document highlighting important aspects of cloud computing. The goal was to provide a baseline for further discussion regarding cloud computing and as a means for comparison of cloud services and deployment strategies. Essential characteristics include on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. Together, these provide a means by which multiple organizational, community, or public consumers to which these services are deployed can each have great individual flexibility and freedom to unilaterally adjust services to fit current and anticipated demands across a range of devices. These essential characteristics and deployment models are associated with one of three service models:

  • Software as a Service (SaaS): The consumer runs applications running on a cloud infrastructure.
  • Platform as a Service (PaaS): The consumer uses the cloud to deploy applications they have created or acquired and that make use of programming languages, libraries, services, and tools provided and/or supported by the provider as part of their platform.
  • Infrastructure as a Service (IaaS): The consumer is provided a base of computer resources such as processors, storage, and networks upon which they can deploy and run software.

Others have noted that the distinction between higher-level Platform and lower-level Infrastructure as a Service found within a large data center is not a crisp line and should be considered together as utility computing.[7]

What is not generally recognized in relation to Cloud Computing is that, as part of the Internet with its foundational concepts of the end-to-end protocol creating a federation of the locals, data centers themselves are housed within their own Local Area Networks (LANs), some of which may be located within broader corporate Campus Area Networks (CANs). As part of a federation of the locals, these data centers should not be seen as centralized servers with overriding authority control, but rather local nodes internetworked with other local nodes to provision hardware and software services, a concept that was underlined within the Essential Characteristics section of the NIST Definition of Cloud Computing.

Wouldn’t it therefore be accurate to consider the research servers (e.g., Prairienet Community Network server computers), the University library servers, and University campus infrastructure servers that serve on- and off-campus associates a Cloud service?

The 'campus cloud' represented by its physical infrastructure: Local Area Network (LAN) end-points connect to Internet Service Providers. These connect to routers within Wide Area Networks (Internet), which in turn connect to campus routers, via backbone cables (mostly fiber). The campus routers, which are part of the U of I campus area network (a cloud?), connect via campus fiber cables to other building routers, switches, and nodes, which form their own LANs. They also connect to routers, switches, other school nodes, and Prairienet servers. These other school connections are made by Ethernet cables, and form their own LAN end-point.
A visualization of multiple LANs within a Campus Area Network and connected to remote LANs via the Internet Wide Area Network.

Wrap Up

As noted earlier in this session, internetworking can happen in many shapes and forms which regularly incorporate the Internet suite of protocols and applications. The key is the level to which we enter into use of an Internet-based tool from a “thing-oriented” compared to a “person-oriented” framing. Through the exercises within this part of the session, we’ve made use of different research methods to explore key social and technical aspects of the Internet suite, seeking to decodify key terms and concepts related to networked information systems.

I have been part of the iSchool at Illinois since 1995, where “we believe in the power of information to change the world,” as noted at the top of our 2022-2027 Strategic Plan. The strategic plan goes on to highlight our innovative research at the intersections of inquiry and engagement, that includes interdisciplinary partnerships across broad communities. Internetworking happens both within the community and through the cloud, across Internet of Things devices on a local area network and local end-point devices across the Internet, within local servers and on server farms. Socioeconomic and sociopolitical frameworks have been introduced over the years, such as through the The Progress & Freedom Foundation and in publications such as “Cyberspace and the American Dream: A Magna Carta for the Knowledge Age,” working to shift to an exclusive supply-side, free market capitalism rooted within technological determinism and radical individualism. Emphasis is placed on removing individuals from their information activist communities, and instead into positions of consumption of data and information resources provided by platforms and services in the Cloud. Bringing together topics introduced in the first two sessions of the Rainbow Unit, we can now see Neil Gershenfeld’s championing the bringing together the virtual world of bits and the physical world of atoms in innovative ways, through the Fab Lab movement and Internet of Things devices and through his opposition to the Bitnet of Things as the supply-side, free market solution to the grassroots Internet of Things alternative. For some economic and political framings, accelerating technological and economic strength can only happen through social and political dominance that focuses on this unique free market capitalist form. But as I’ve presented various aspects of the Rainbow Unit nationally and internationally, there have been a number of companies and community organizations that have provided their vigorous affirmation of the need for work at the intersection of inquiry and engagement beyond such a singular, hyper-individualized socio-political and economic lens.

If we are to address the opportunities and urgent needs of the day, there is a need for both community and corporate stakeholders to join in collective leadership. It may start through service and outreach, but needs to actively work beyond these to engagement that is reciprocal and mutually beneficial. Further, this requires the voices of diverse groups across cultures and disciplines. And as we’ve explored throughout this book, that requires inquiry that brings in the voices of the marginalized and oppressed. This can often start through works such as social justice storytelling, using story data, information, knowledge, and wisdom to counter the dominant think-oriented narrative through concealed stories to respond to stock stories, resistance stories to highlight injustices, and emerging and transforming stories to (re)construct knowledge built on concealed and resistance stories. But as we move forward within the Rainbow Unit, we’ll also see the importance of such inquiry and engagement to move into all realms of creative endeavors. This is true now more than ever, as noted within the iSchool at Illinois’s strategic plan’s “Intersections of Inquiry and Engagement” section:

“Information in the form of data underpins vast initiatives, including artificial intelligence (AI), machine learning, data science, big science, and more. Poor quality data, poorly integrated and conserved data, and unacknowledged data biases can corrupt these efforts.”

As we’ve explored in this session, the infrastructure of the Internet provides an amazing opening, but also some significant hurdles, for us to build from “person-centered” digital internets past and present, and to also open new critical lenses to further challenge the dominant “thing-oriented” framings through new pathways as we move forward within the information sciences.

Comprehension Check

  1. Mobile Beacon and Mobile Citizen are providers for such devices, dedicated to serving schools, libraries, and nonprofits.
  2. Crawford, Susan P. Fiber: The Coming Tech Revolution and Why America Might Miss It (New Haven: Yale University Press, 2018), 6.
  3. See Nelson Machado Junior, “A Brief Introduction To 5G Technology: What you have to know about the 5th generation of cellular networks”, Medium, January 21, 2021. Accessed November 16, 2022,
  4. P. Mockapetris, “Domain Names – Concepts and Facilities,” Network Working Group, November 1983,
  5. P. Mockapetris, “Domain Names – Concepts and Facilities, Request for Comments 1034,” Network Working Group, November 1987,
  6. “About Cloudflare,” Cloudflare, accessed July 18, 2020,
  7. Armbrust, Michael, Armando Fox, Rean Griffith, Anthony D. Joseph, Randy Katz, Andy Konwinski, Gunho Lee, et al., “A View of Cloud Computing,” Communications of the ACM 53, no. 4 (April 2010): 50–58.


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A Person-Centered Guide to Demystifying Technology, 2nd Edition Copyright © 2023 by Martin Wolske Copyright © 2023. Copyright “Ideating and Iterating Code: Scratch Example” © 2020 Betty Bayer and Stephanie Shallcross. Copyright “Introducing the Unix Command Line” © 2020 Martin Wolske, Dinesh Rathi, Henry Grob, and Vandana Singh. Copyright “Security and Privacy” © 2020 Sara Rasmussen. Copyright “Storytelling in the Information Sciences” © 2023 Yingying Han and Martin Wolske. This book is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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