How Do Computers Communicate Over Networks?
For starters we need an analogy to demonstrate how a computer network functions and how computers transmit, receive, and interpret data over those networks. First off, you know what the U.S postal system is, you know how to send a letter to someone through the mail, and you know you can require an acknowledgement from the receiver (such as certified mail). Computer Networking works much the same as our standard postal systems do. Just like you need an address in order to send someone a letter in the mail, you also need an address in order to communicate between computers over the internet. And, just like we use logical addresses to send a letter in the mail (say St Louis MO 63135), and we use physical addresses (such as a residence or business location “3700 N. Broadway BLVD”), networks also use logical addresses (IP addresses), and computers have physical addresses, just like a home or business location does.
Think of it this way, if you didn’t have a phone number or address for someone you needed to contact, how would you get a hold of them to communicate with them at all? You couldn’t. The Internet, computers, and their related technologies use a plethora of protocols, and standard agreed upon rules in order to communicate information from one source ( a computer) to another source(another computer). Some of these protocols used in networking are TCP/IP, IP addresses, MAC addresses, connectionless, and connection oriented logical networking protocols, etc. We’re going to provide you with a comprehensive look at how computers communicate using these various protocols and standards step by step.
Now, before we move forward, we need to clarify a few things so that some of the terminology used here will make sense to you. What is a “standard”, and what is a “protocol.” A protocol is an agreed on set of rules and or ways of doing something, and in our case of computer networking, it also represents agreed upon ways of communicating across networks. A standard is something that is considered as a widely accepted practice of the way something in particular is done. For instance, virtually all non commercial electrical wall sockets in the U.S. are rated electrically at 115 volts AC. This is a standard, and this is the very reason why electronics manufacturers must make their products to function within this electrical standard, if they didn’t, the devices they create wouldn’t be able to function properly and most likely the product itself would be damaged, along with the electrical system it was connected too. And if you have a set of rules that you are told you must abide by at work or school for instance, this is a set of protocols, or procedures that are expected to be followed to keep things working smoothly.
Without standards and protocols, there would be no such thing as computer networking since all devices would be virtually incompatible.
Now, Everyone uses the internet these days for something, but what most don’t realize is that when they enter the name of a website into their browser search bar and hit enter, they are actually sending a request to another computer (DNS server) somewhere across the internet and asking that particular system to find the “address” of the website or entity they are looking for. This address is an “IP Address” (Internet Protocol) and it is used to identify a particular website or entity somewhere across the internet. And, just like you need an address in order to send a letter in the mail or a phone number to contact a friend or associate, you also need an address (Logical Identifier) in order to communicate with others, including computers across the internet. If you typed in say Walmart.com in Google search, Google then sends your request to a DNS (Domain Name System) Server that looks up the IP address that corresponds to the name of the website you are searching for. DNS or “Domain Name System” is a name to address resolution protocol, and it’s at the heart of communications across the internet and “world Wide Web.”
Without DNS you would have to remember and know the address for every website, internet application, or organization that you wanted to communicate with across the internet. Which is easier to remember, a name or an address? Think about it! If you wanted to go to Walmarts website, which would be easier to enter into your browser search bar, Walmart.com or 126.96.36.199? Which would be easier to remember? The latter you just saw is a logical address (IP Address) of the website, or another way to put it, the address of the network that the website resides on. In this sense Domain Name Servers do the hard work for us. They receive your request for information, they then look up a logical address that corresponds to that requested information and forward the information back to you through the use of a browser, ftp, network application, computer system, etc.