Introduction to TCP/IP and other network protocols

Introduction to TCP/IP and other network protocols 1. TCP/IP is a communication protocol for the Internet. Computer Communication Protocols are descriptions of the rules that computers must comply with in order to communicate with each other. TCP/IP refers to the Transmission Control Protocol/Internet Protocol (Transmission Control Protocol/Internet Protocol ). TCP/IP defines how electronic devices (such as computers) connect to the Internet and how data is transmitted between them. TCP (Transmission Control Protocol)-communication between applications UDP (User packet protocol)-simple communication IP (Internet Protocol) between applications) -communication between computers ICMP (Internet message control protocol)-DHCP for errors and statuses (Dynamic Host Configuration Protocol) -Dynamic addressing TCP uses a fixed connection TCP for communications between applications. When an application wants to communicate with another application over TCP, it sends a Communication Request. This request must be sent to an exact address. After both parties "Shake hands", TCP will establish a full-duplex communication between the two applications. This full-duplex communication will occupy the communication line between two computers until it is closed by either or both parties. UDP is similar to TCP, but it is simpler, and the reliability is lower than TCP. An IP address is a connectionless IP Address used for communication between computers. An IP address is a connectionless communication protocol. It does not occupy the communication line between two computers that are communicating. In this way, the IP address reduces the need for network lines. Each line can meet the communication needs of many different computers at the same time. Messages (or other data) are divided into small independent packages and transmitted between computers over the Internet. The IP address is responsible for routing each packet to its destination. When an IP packet is sent from a computer, the IP router will arrive at an IP router. The IP router is responsible for routing the package to its destination, either directly or through other routers. In the same communication, the path of a package may be different from that of other packages. The router is responsible for correctly addressing traffic, network errors, or other parameters. TCP/IP means that TCP/IP and IP work together. TCP is responsible for communication between application software (such as your browser) and network software. IP addresses are responsible for communication between computers. TCP is responsible for dividing and loading data into IP packets, and then re-combining them when they arrive. The IP address is responsible for sending the package to the recipient. TCP/IP uses 32 bits or 4 digits between 0 and 255 to address the computer. Each computer must have an IP address to connect to the Internet. Each IP package must have one address before it can be sent to another computer. The IP address contains four numbers: This is your IP address: 116.4.147.99 TCP/IP uses four numbers to address the computer. Each computer must have a unique 4-digit address. Numbers are separated by dots between 0 and 255. For example, 192.168.1.60 32 bits = 4-byte TCP/IP uses 32 bits for addressing. The size of a computer is 8 bits. Therefore, TCP/IP uses 4 bytes. A computer byte can contain 256 different values: 00000000, 00000001, 00000010, 00000011, 00000100, 00000101, 00000110, 00000111 until 00001000. Now you know why the TCP/IP address is 4 numbers between 0 and 255. The domain name contains 12 Arabic numbers that are hard to remember. It is easier to use a name. The TCP/IP address is called a domain name. W3school.com.cn is a domain name. When you type an image http://www.w3school.com.cn Such a domain name is translated into numbers by a DNS program. In the world, a large number of DNS servers are connected to the Internet. The DNS server is responsible for translating domain names into TCP/IP addresses and updating systems with new domain name information. When a new domain name is registered with its TCP/IP address, DNS servers around the world update this information. TCP/IP is a large set of different communication protocols. The protocol family TCP/IP is a large set of different communication protocols based on the two original protocols TCP and IP. TCP-Transmission Control Protocol (TCP) is used to control data transmission from applications to networks. TCP is responsible for dividing data into IP packets before data transmission, and then reorganizing them when they arrive. IP-Internet Protocol IP addresses are responsible for communication between computers. The IP address is responsible for sending and receiving packets over the Internet. HTTP-Hypertext Transfer Protocol (HTTP) is used for communication between web servers and web browsers. HTTP is used to send requests from the web Client (browser) to the web server and return content (webpage) from the web server to the web Client ). HTTPS-secure HTTPHTTPS is responsible for secure communication between web servers and web browsers. As a representative application, HTTPS is used to process credit card transactions and other sensitive data. SSL-Secure Socket Layer SSL protocol is used to encrypt data for secure data transmission. SMTP-Simple Mail Transfer Protocol SMTP is used for email transmission. MIME-multi-purpose Internet Mail Extensions MIME protocol enables SMTP to transmit multimedia files, including audio, video, and binary data, over TCP/IP networks. IMAP-Internet Message Access Protocol IMAP is used to store and retrieve emails. POP-Post Office Protocol POP is used to download emails from the email server to your PC. FTP-the file transfer protocol FTP is used to transfer files between computers. NTP-The Network Time Protocol NTP is used to synchronize time (minutes) between computers ). DHCP-Dynamic Host Configuration Protocol DHCP is used to allocate Dynamic IP addresses to computers on the network. SNMP-Simple Network Management Protocol (SNMP) is used to manage computer networks. LDAP-Lightweight Directory Access Protocol LDAP is used to collect information about users and email addresses from the Internet. ICMP is responsible for handling errors in the network. ARP-Address Resolution ProtocolARP-used to find the hardware Address of the computer NIC based on IP addresses. RARP-Reverse Address Resolution ProtocolRARP is used to find the IP Address of the computer NIC based on the hardware Address through the IP Address. BOOTP-Boot ProtocolBOOTP is used to start a computer from the network. PPTP-Point-to-Point Tunneling Protocol PPTP is used for connection (Tunnel) between private networks ). Email is one of the most important applications of TCP/IP. You won't use... you won't use TCP/IP when writing emails. When writing emails, you use e-mail programs, such as Lotus Notes, Microsoft Outlook, or Netscape Communicator. (W3school members like to use the well-known Foxmail .) The email program will use... your email program uses different TCP/IP protocols: use SMTP to send emails use POP to download emails from the mail server use IMAP to connect to the mail server SMTP-Simple Mail Transfer Protocol SMTP protocol for sending emails. SMTP is responsible for sending emails to another computer. Normally, an email is sent to an SMTP server and then to another (or several) server. Then, it is finally sent to its destination. SMTP can also transmit plain text, but it cannot transmit binary data such as slices, sounds, or movies. SMTP uses the MIME protocol to send binary data over the TCP/IP network. The MIME protocol converts binary data to plain text. POP-Post Office Protocol POP protocol is used by the mail program to retrieve emails from the mail server. If your email program uses POP, once it connects to the email server, all your emails will be downloaded to the email program (or called the mail client ). The IMAP-Internet Message Access Protocol is similar to POP, and the IMAP protocol is also used by email programs. The main difference between the IMAP protocol and the POP protocol is that if IMAP is connected to the email server, it will not automatically download the email to the email program. IMAP enables you to view emails on the mail server before downloading them. With IMAP, you can download these emails or simply delete them. For example, you need to access the email server from different locations, but you only want to download the email when you return to the office. IMAP is useful in this case.