Learn about the working structure of Internet infrastructure

Jeff Tyson

One of the best things about the Internet is that nobody really owns it. It is a collection of global networks, both large and small. These networks connect to each other in different ways to form a single entity, which we still know as Internet names. In fact, this name comes from the idea of inter connected net works, taken from these two words.

From the first days of its founding in 1969, the Internet has grown from four host computer systems to tens of millions of them. Although no one owns the Internet alone, it does not mean it does not need to be checked and maintained in many different forms. The Internet Society, a nonprofit group founded in 1992, oversees the formation of policies and protocols to define how we will use and interact with the Internet.

In this article, we will introduce you to the basic structural issues of the Internet. You will learn more about the basics of Domain Name System (DNS), network access points (NAP) and backbone networks. However, first we will show you how to connect your computer to other computers.

Internet: Network architecture

Every computer connected to the Internet is considered part of the network, even your home computer. For example, you can use a modem and dial up to connect to an Internet Service Provider (ISP). In the workplace, you can be part of your local Local Area Network (LAN) network, but you can still connect to the Internet using an ISP your company has signed. co offer this service. When connecting to your ISP, you will become part of their network. The ISP can then connect to a larger network and become part of that network again. The Internet is simply the network of networks of networks.

Most major media companies have their own dedicated backbone networks to connect between different geographic regions. In each of these areas, companies have a presence - Point of Presence (POP). POP is a location where internal users can access the corporate network through an internal phone number or a private line. What is amazing here is that there is no network control problem, but rather some high-level networks that connect to each other through Network Access Points (NAP).

Example of the Internet

Here is an example. Imagine that company A is a big ISP. In every major city, this company A has a POP. POPs in every city have modem connection systems so that ISPs can dial in. The company installed fiber-optic lines from a telephone company to connect these POPs together.

Next, company B is also an ISP. Company B built large buildings in major cities and corporations located on their Internet servers in these buildings. Company B is so big that it can run their own fiber optic cables between buildings so they can be connected.

In this scenario, all customers of Company A can exchange with each other and all customers of Company B can communicate with each other, but there is still no way to exchange among customers. goods of these two companies together. Therefore, Company A and Company B have an agreement to connect via NAP in other cities, when traffic between these two companies is circulated between networks at NAP.

In fact, there are dozens of large Internet service providers connected to each other in NAPs in many different cities, and there are billions of bytes of data transferred back and forth between networks. through these NAPs. The Internet is a collection of giant corporate networks that have agreed to connect with each other at NAPs. In this way, every computer in the Internet has the ability to connect with each other.

Router function

All of these networks rely on NAP, backbone and routers to communicate with each other. There is an unbelievable problem with the fact that a message can leave one computer and move almost all over the world through different networks, reaching another computer in a very short amount of time ( calculated by fractions of seconds).

Routers show where to send information from one computer to another, they are special computers used to send your messages to destinations in thousands of different routes. A router has two separate but related issues:

1. Ensure that information does not go into unnecessary places and requires a large amount of data to avoid interfering with connections of unrelated addresses (addresses are not destinations).
2. Make sure the information reaches the correct destination as intended

During the implementation of these two tasks, the router also has the effect of communicating between two separate computer networks. It will connect these two networks together, sending information from one network to another and vice versa. Protect networks, prevent traffic on an unnecessary network from spilling into another network. Do not care about the number of attached networks, the same basic operation and functions of the routers. The Internet is a large network established from tens of thousands of smaller networks so the use of routers is absolutely necessary.

Backbone network

The National Science Foundation (NSF) built a high-speed backbone network in 1987. This backbone is called NSFNET , which is a T1 backbone to connect 170 smaller networks together and operate at a rate of 1,544 Mbps. IBM, MCI and Merit worked with NSF to create the backbone network and developed on T3 (45Mbps) backbone systems the following year.

Typical backbone network is fiber optic backbone. These backbone lines have many fiber optic cables combined together to increase capacity. Fiber optic cables are designed under different types based on optical carriers, such as OC-3, OC-12 or OC-48. The OC-3 line can transmit up to 155Mbps and the OC-48 can transmit 2,488 Mbps (2,488 Gbps). Compared to the traditional 56K modem, you can see how fast the backbone network is faster.

Today many companies operate on their own high-capacity backbone networks, all of which are connected to NAPs around the world. In this way, people on the Internet, wherever they are, what they use and what they use are capable of communicating with each other. The whole Internet is a huge deal between companies for easy communication.

Internet protocol: IP address

Every computer on the network has a unique identifier called an IP address . IP is the abbreviated name of Internet Protocol, a language that computers use to communicate with each other on the Internet. A protocol is a pre-defined way that someone wants to use a service to communicate with that service. 'Someone' here may be one person, but usually it is a computer program such as a web browser.

A typical IP address looks like this:

216.27.61.137

To make it easier to remember, IP addresses are presented in decimal format like the above. However, computers are communicating in binary form. The decimal fraction of the above IP address will be presented in binary form when the computers work:

11011000.00011011.00111101.10001001

The four numbers in an IP address are called octets , because they are represented by 8 binary numbers. If you use all these locations together, you will have 32 bits, which is why IP addresses are called 32-bit numbers. Since one of these 8 positions has two different states (1 and 0), it can represent 2 ⁸ or 256 combinations. Therefore, each octet can contain values ​​from 0 to 255. The combination of this 2 ³² you will get 4,294. 967,296 values.

Of the nearly 4.3 billion combinations there are some values ​​that are limited in use, it will not be like a typical IP address. For example, the 0.0.0.0 address is reserved for the default network and the address 255.255.255.255 is used for broadcast.

Octets do a different purpose than simply dividing numbers. They are used to create IP address classes that can be assigned to a business, government or an entity based on size and demand. The octets are divided into two parts: the Net part and the Host part. The Net section always contains the first octet. It is used to distinguish which network the computer belongs to. Host (sometimes referred to as a Node ) to distinguish computers in the network together. The Host section always contains the remaining octets. There are 5 IP classes plus special addresses. To find out more about IP addresses we will set aside a post to show you what is an IP address.

Internet protocol: Domain name system (DNS)

When the Internet was in its infancy, it considered a number of small computers connected by modems and phone lines. You can only create connections by providing the IP address of the computer you want to establish a link to. For example, a typical IP address might be 216.27.22.162. Everything will work fine if there are only a few hosts, but it will become cumbersome and hard to remember when more and more systems are online.

The first solution to this problem is a simple text file maintained by Network Information Center that maps names to IP addresses. Increasingly, this document becomes too big in management. In 1983, the University of Wisconsin created the Domain Name System (DNS), to map text names to IP addresses automatically. In this way, you only need to remember the domain name www.quantrimang.com instead of having to remember its IP address.

URL: Uniform Resource Locator

When you use the Web or send an email, you often use a domain name to do that. For example, the Uniform Resource Locator (URL) " http://www.quantrimang.com " contains the domain name quantrimang.com. Each time you use a domain name, you will use Internet DNS servers to translate domain names that people can read into machine-code IP addresses.

First-level domains, called first-level domain names, include .COM, .ORG, .NET, .EDU and .GOV. Within each of these top-level domains there is a large list of second-level domains. For example, in the first level domain .COM here is: QuanTriMang.com

Each domain in the top-level .COM top domain must be unique. From the left most and after www, it is the host name. It specifies the name of a certain machine (with a specific IP address) in a domain. A given domain can contain millions of host names as long as they are unique within that domain.

DNS servers accept requests from other programs and name servers to convert domain names into IP addresses. When a request is made, the DNS server can do one of the following four things:

1. Can answer a request for an IP address because it already knows the IP address for the requested domain.

2. You can contact another DNS server and find out the IP address for the requested name. This search may have to be done several times.

3. It may say: 'Don't know the IP address for the domain you require, but this is the IP address for a DNS server it knows.'

4. It is possible to return an error message because the requested domain name is invalid or does not exist.

An example of DNS

Let's say you type the URL www.quantrimang.com into your browser. The browser will contact the DNS server to retrieve the IP address. The DNS server will start searching its IP address by contacting one of the root DNS servers. The root servers know the IP addresses of all DNS servers that manage first-level domains (COM, .NET, .ORG, .). Your DNS server will ask the original server for www.quantrimang.com, the root server will say it does not know the IP address for www.quantrimang.com but this is the IP address for the machine for DNS.

Your domain server then sends a query to the .COM DNS server asking if it knows the IP address for www.quantrimang.com . The DNS server for the .COM domain knows the IP addresses for the domain server managing the domain www.quantrimang.com , so it returns the requested issues.

Your domain name server will contact the DNS server on www.quantrimang.com and ask if it knows the IP address for www.quantrimang.com . And here the www.quantrimang.com DNS server will respond to the IP address for your DNS server, then the DNS server will return it to the browser, and can contact the server about www.quantrimang. com to get the content of the page.

One of the aspects that make these operations work is that there are many DNS servers. Many DNS servers are at levels, so if a DNS server fails, there are many other servers managing the requests. Another aspect is storage. When a DNS server resolves a request, it will save the IP address it receives. Once you have created a request for the original DNS server to the .COM domain, it will know the IP address for the DNS server managing the .COM domain, so it will not be confused with the original DNS servers for that information. . DNS servers can perform this task with every request and this storage is also helpful when encountering some problems.

Server (Server) and Internet client (Client)

All computers on the Internet are either servers or clients. However there is a distinction between them. Computers capable of providing services to other computers are called servers. The computer that is used to connect to those services is the client. There are many Web servers, email servers, FTP servers and therefore it can serve many needs of all users worldwide.

When you connect to www.trantrimang.com to read the information pages, you will be a user using your client to access the server containing the content of this page. The server finds the page you requested and sends it to you. Clients accessing the server do so with a specific intention, so the clients direct their requests to a specific software server running on the server. For example, if you are running a web browser on your computer, it will notify the Web server on the server, not the email server.

A server that has a static IP address does not change frequently and your home computer performs dial or ADSL through a modem with an IP address changed by the ISP each time you connect. That IP address is unique to your current session and may be different in subsequent connections. In this way, an ISP only needs one IP address for each modem that it supports, not one IP for one customer.

Ports and HTTP

Any server that provides available services uses numbered ports - one of the services available on the server. For example, if a server is running a Web server and an FTP file transfer protocol server, the Web server will be available on port 80, and the FTP server will be available on port 21. The clients connect to the translation. service at a certain IP address and on a specific port number.

When a client connects to a service on a particular port, it can access the service using a certain protocol. Protocols are usually documents and simply describe how the client and server will communicate with each other. Every Web server on the Internet adapts to the hypertext transfer protocol (HTTP).

Networks, routers, NAP, ISPs, DNS and other servers all make the Internet available. It's no surprise that you realize that all this information is sent around the world in a fraction of a millisecond. They are very important components in modern life, without them there will be no Internet. And without the Internet, life will be very difficult for us.