Computer networks have become the backbone for human activities today. Many human activities are facilitated by the existence of computer networks. Starting from business, finance, commerce, to transportation, has been aided by the benefits of this computer network .
In the development of the history of computer networks its development has created several key elements. One is the network protocol. Uh, what's a network protocol? And what it functions
Protocol is a standard that governs the occurrence of relationships, communication, and data transfer between two or more computer points. Protocols can be applied to hardware, software or a combination of both. At the lowest level, the protocol defines the connections on the hardware.
The network protocol itself consists of several kinds. The various network protocols can be explained in the form of TCP / IP Protocol Suites. TCP / IP Protocol Suites is a group of protocols that manage data communications in the process of exchanging data from one computer to another within the internet network that will ensure data transmission to the destination address.
TCP / IP Protocol Suites consists of 4 layers, namely Application Layer, Transport Layer, Internet Layer, and Network Access Layer. We will explain the various network protocols based on TCP / IP Protocol Suites. Here is the explanation:
A. Application Layer
1. Domain Name System (DNS)
The definition of DNS itself is a system used to search the name of a computer in a network that uses TCP / IP (Transmission Control Protocol / Internet Protocol). DNS is commonly used in Internet-connected applications such as web browsers or e-mail. DNS helps map the host name of a computer to an IP address. In addition to being used on the Internet, DNS can also be applied to private networks or intranets where DNS has advantages such as:
- Easy, because the user is no longer bothered to remember the IP address of a computer. Users just remember the host name (Computer name) only. For example, the site you're currently accessing is fairly easy to access at the "dosenit.com" address rather than the address "18.104.22.168"
- Consistent, because the hostname will not change even if the IP address of a computer changed
- Simple, because the user only use one domain name to search for a computer name on the Internet or on the Intranet
2. POP3 (Post Office Protocol version 3)
POP3 is a protocol used to retrieve e-mail from an e-mail server. The POP3 protocol was created due to the design of the electronic mail system (e-mail) requiring an e-mail server that holds the e-mails temporarily until the e-mail is retrieved by the eligible recipient.
3. IMAP (Internet Message Access Protocol)
IMAP is a standard protocol for accessing e-mail from a server. Its function is similar to POP, but IMAP offers the advantages of choosing e-mail messages to be retrieved, creating folders on the server, searching for specific e-mail messages, even deleting existing e-mail messages. This capability is better than POP which only allows its users to retrieve all existing messages without exception.
4. HTTP (Hypertext Transfer Protocol)
HTTP is a protocol used by WWW (World Wide Web). HTTP defines how a message can be formatted and sent from server to client. HTTP also controls what actions the web server and the web browser should take in response to the commands of this HTTP protocol.
The example of the implementation is as follows: when you type an address or URL in a browser, then the browser will send HTTP commands to the web server. The web server will then accept this command and perform the activity according to the command requested by the browser. The result of that activity will be sent back to the browser to be displayed to us
5. FTP (File Transfer Protocol)
FTP is the standard protocol for file transfer between computers within an internetwork. FTP uses only the standard authentication method, which uses the username and password sent in the form of unencrypted data. Registered users can use their own username and password to access, download and upload the files they want. Unregistered users can also use the anonymous login method, which is by using an anonymous username & password filled with the e-mail address. An FTP server is accessed by using a Universal Resource Identifier (URI) that has the format "ftp: // servername".
6. SSH (Secure Shell)
SSH is a network protocol that enables secure exchange of data between two computers. SSH can be used to control computers remotely send files, create encrypted tunnels, and more. This protocol has advantages over similar protocols such as Telnet, FTP, because SSH has its own authentication system, authorization, and encryption type.
B. Transport Layer
1. TCP (Transmission Control Protocol)
TCP is a protocol within the most commonly used network network layer due to TCP overload of error correction. By using TCP protocol, then the delivery process will be guaranteed. This is due to the existence of a section for a method called flow control. Flow control will determine when data should be sent back, and when to stop the previous packet data flow, until the data is successfully sent. This happens because if the data packet successfully sent, it can happen "crash data. When a collision occurs, the client will retrieve the packet from the server until all packets are successfully sent and identical to the original data.
2. UDP (User Datagram Protocol)
UDP is one of the TCP / IP Protocol Suites transport layer protocols that supports unreliable, un-connectionless communication between hosts in a network that uses TCP / IP . Here are some features of UDP:
- Connectionless (no connection): UDP messages will be sent without having to negotiate the connection between two hosts that want to exchange information.
- Unreliable (Unreliable): Messages UDP will be sent as a datagram without any sequence number or "acknowledgment" message. Application layer protocols running over UDP must recover messages lost during transmission
- UDP provides a mechanism for sending messages to a particular application layer protocol or process within a host in a network that uses TCP / IP. The header in the UDP datagram contains the Source Process Identification and Destination Process Identification fields.
- UDP has a 16-bit checksum count feature for the entire UDP message.
3. Internet Control Message Protocol (ICMP)
In the Transport layer, ICMP is different from TCP and UDP. ICMP can not be used directly by the user's network app, except in the Ping application that sends ICMP Echo Request (and receives Echo Reply) messages to determine whether the destination host is reachable and how long the packet sent is returned by the destination host
C. Internet / Network Layer
1. IP (Internet Protocol)
- Connectionless, ie every packet of data sent a moment will go through a route that has been determined by itself. Datagram packets will go through the route specified by each router. This allows the entire datagram to arrive at the destination even in different sequences because it takes a different route.
- Unreliable, the IP protocol does not guarantee the datagram sent to the destination. but will only do the best possible effort for the package to be delivered to the destination ( best effort delivery ) .
D. Network Layer
1. Point-to-Point Protocol (PPP)
PPP is a network packet encapsulation protocol widely used on Wide Area Network (WAN). This protocol is an industry standard that runs on the data-link layer and was developed in the early 1990s in response to problems that occur in the Serial Line Internet Protocol (SLIP) protocol, which only supports static IP addressing to its clients. This protocol can work faster, there are features of error correction, and the existence of a negotiation session dynamically without any intervention from the user. In addition, this protocol also supports many other network protocols simultaneously.
2. Serial Line Internet Protocol (SLIP)
SLIP is a protocol that allows the transfer of IP data over telephone lines. This system requires one server computer as its container. This protocol is now superseded by PPP standards that have a higher processing speed.
So many of our discussions this time around the various network protocols. Hopefully this article can add to your knowledge about network protocols.