The Internet

        The Internet is perhaps the most important contribution to the world that Vint Cerf has achieved in his lifetime. In order to provide a more straightforward understanding, this page will explain how the Internet works.

The Internet is not necessarily the network itself. Today, commonly used networks that connect to the Internet are XFinity Comcast and AT&T, for example. They connect to the Internet, which is done by simply following protocol for how the information transfers must work to succeed.

        Figure 1. The two AT&T-connected devices can easily send emails to each other because they both follow the same protocol. The AT&T device can also email an XFinity device, because they both use the same protocol. However, if, for example, Verizon refuses to obey Internet Protocols, connection between Verizon devices and AT&T devices will fail.

        Expanding on Figure 1, if both devices follow both the Transfer Control Protocol (TCP) and Internetworking Protocol (IP), the transaction should work.

        The Internet is a packet switched network. This means that information being sent is always sent in binary (0s and 1s only) and is broken down into “packets,” sent off on different routes to their destination. When all of the packets arrive, they are reassembled into the original message. The packets move from router to router until they find the router that is nearest the recipient device. There are paths between different routers, and packets are not always sent on the most direct route. They will be sent on the quickest one. This means that the Internet is decentralized. There is no central hub, and if one route is blocked, information will be sent around it. Packets also move at the Speed of Light, and as such, they can be sent thousands of miles almost instantly.

        Figure 2. The sample email “Hello!” with no subject is broken down into six packets, H, E, L, L, O, and !. Each one is sent on a different route to its destination. When all of them arrive, only then will it finish sending the message. They are all sent on completely different routes. Images and other large files take longer to send; it takes longer for the packets to arrive because there are more of them, and they may use their own URL (Uniform Resource Locator). Note that the packets in the real Internet are converted to binary (0s and 1s only) and the size depends on the algorithm for breaking down the packets. Usually, companies try to get the smallest packets possible.

      Every website is hosted on a computer with an IP Address. Currently, they are usually 32 binary digits, 8 in each of four sections. The first number represents country, the second province, region, or state, the third subnetwork, and the fourth being the individual device. A sample IP Address would be 122.78.102.92. This would be converted to binary. That is the website’s precise location, but in browsing, most people search for a website’s domain name. Domain names are, for example, www.google.com, www.pbs.org, www.usgs.gov, and www.synertel.net. The domain name usually ends with one of those four end phrases, demonstrating that the site is either commerical, an organization, run by the government, or its own network. To identify IP Address by Domain Name, a computer will ask a DNS computer, or Domain Name System computer. This translates domain name to IP Address and sends it back to one’s computer, to load the right website. Additionally, DNS Systems are separated by .com, .org, .gov, and .net.

        Figure 3. The user wants to get to www.google.com. Their two IP Address servers are labelled 8.8.8.8 and 8.8.4.4. (That is Google’s real IP Address.) The laptop that the user has is “asking” a .com DNS to translate www.google.com into its IP Address, either 8.8.8.8 or 8.8.4.4. Whichever one is sent back, the user is sent to that Google server.

      Individual devices also have IP Addresses. When connecting to WiFi or another form of the Internet, the WiFi antenna, Ethernet router, or other connector of the Internet will assign the device the IP Address that it will use until it disconnects from the Internet.

        Figure 4. The user, when they connect their laptop to the Internet, is assigned their IP Address. Later, they take their laptop to a different WiFi router and are assigned a new IP Address. When they return home to reconnect, the first three parts of the IP Address remain the same, because it is in the same country, same state or province, and same subnetwork. 

        The Internet has one more important part: security.

    Figure 5: Note how, on the top of this person’s web browser, it says “https” rather than “http,” and has a green lock icon to the left of it. This person is using a safe website. If it lacks a green lock or says “http” rather than “https,” it is an unverified website that could be potentially dangerous. While the Google engine is secure, Bing is an unverified search engine.

        Cybersecurity and protection against hacking is an ongoing concern. While 90% of all hacks are user accidents, and only 10% are cyberattacks, it is still helpful to stop the attacks. This is done through encryption. Usually, there will be a “public key” that ciphers a message, but it can only be deciphered with a confidential “private key.” In most computers, the message is created, but the user cannot see what it translates to because it is changed through the public key, and only certain computers can decipher the message. As an analogy, imagine an apartment mailboox. Anyone can use a key to deposit a message, but that does not work for reclaiming the messages in the box. Only the owner with a private key can do that.

       Figure 6. The user on the left is trying to email the user on the right “Hello!”, with no subject. Since this is a private email conversation, only these two devices have the private key necessary for deciphering this code. The message gets scrambled up into “8dbu9c”  and gets sent, but before the other person receives it, the private key that they have for this message returns it to “Hello.” If a hacker were to enter the conversation, he would see “8dbu9c,” but would be unable to decipher the message due to the fact that he does not have the private key.

       The Internet is a vast network spanning the globe. By simply following TCP and IP, a device can be linked to this global, communal network. This is the single most important thing Vint Cerf has done in his lifetime that is the foundation for all of the work he has done since.