Service content of the tcp ip protocol set

The tcp ip protocol we usually call is not only a set of two protocols, but also a set of multiple protocols. Is it difficult? What are its meanings and specific services? And what role does the Network play in? Let's take a look at the content below.

Service types supported by TCP

In any case, the tcp ip protocol set. Provides some "low-level" functions for applications, including IP, TCP, and UDP. Other application protocols are used to execute specific tasks, such as transferring files between computers, sending emails, or finding out who is registering with another computer. Therefore, the most important "commercial" TCP/IP Services include:

◆ File Transfer for File Transfer.

File Transfer Protocol (FTP) allows users to obtain files from one computer to another, or send files to another computer. In terms of security, you need to specify a user name and password for using other computers. It is different from Network File System (NFS) and Netbios. Once you access files in another system, you must run FTP at any time. In addition, you can only copy an object to your machine to use it. (FTP description in RFC 959)

◆ Remote login

Network Terminal protocol TELNET allows users to log on to any computer on the network. You can start a remote process to connect to the specified computer until the process ends and the content you typed is sent to the specified computer. It is worth noting that you are actually talking to your computer. The TELENET program makes your computer disappear throughout the process, and each character you typed is sent directly to the logged-on computer system. Generally, this type of remote connection is a type-based dial-up connection, that is, after the dial, the remote system prompts you to enter the registration name and password to exit the remote system, and the TELNET program will exit, you talked to your computer again. The TELNET tool in microcomputer generally contains a terminal simulation program.

◆ Computer Mail

Allows you to send messages to users on other computers. Generally, people tend to use one or two specified computers. In the computer mail system, you only need to add information to the mail file of another user. However, the problem arises, the microcomputer environment is different, and the macro (MICRO) is also important) it is not suitable for receiving computer mail. To send an email, the mail software wants to connect to the target computer. If it is a microcomputer, maybe it has been shut down, or is running another application? For this reason, a large system is usually used to process these emails, that is, a running mail server. The email software is an interface for users to retrieve emails from the email server.

Any tcp ip protocol set tool provides these services. These traditional application functions have always played a very important role in the network based on the TCP/IP protocol set. The current situation is somewhat changed, and the usage of these functions has also changed, such as the transformation of old systems and the development of computers. Various installation versions have emerged, such: microcomputer, workstation, minicomputers, and giant computers. These computers seem to work together to complete a specified task. Although sometimes it seems that they only use a specified computer, they get services from other computer systems through the network. The Server is a system that provides specified services for other users on the network. The Client is another computer system that obtains such services. (It is worth noting that the Service/client is not necessarily a different computer, but may be a different running program on the same computer ). The following are some typical services on the computer that can be called on the tcp ip network.

◆ Network File System (NFS)

This method of accessing files on another computer is very similar to the popular FTP. A Network File System provides disk or device services without requiring a specific network utility to access files of another system. You can simply think of it as an additional disk drive. This extra "virtual" disk drive is the disk of other computer systems. This is very useful. You only need to increase the disk capacity of several computers, so that other users on the network can access it, not to mention the economic benefits, it also allows several computers to share the same files. It also makes system maintenance and backup easy, because it does not have to worry about upgrading and backing up a large number of files on different machines.

◆ Remote printing)

Allow you to use printers on other computers as if they were directly connected to your computer.

◆ Remote execution)

Allows you to request special programs to run on different computers. Remote execution is useful when you run a program on a very small computer that requires resources from a large computer.

◆ Name Server)

In the TCP/IP protocol, a large number of names, including user names, passwords, names, network addresses, and accounts, are required during system installation, managing these is boring. Therefore, the data is stored in a small system, and other systems access the data through the network.

◆ Terminal Server (Terminal servers)

Many terminal connection and installation do not directly connect the terminal to the computer. Instead, they are connected to the terminal server. A terminal server is a small computer that only needs to know how to run TELNET (or other protocols used to complete remote logon ). If you want to connect your terminal, you only need to enter the name of the computer you want to connect. Usually there may be several such connections at the same time, then the terminal server uses the quick switch technology to switch.

Some of the Protocols described above are defined by Berkeley, Sun, or other organizations. Therefore, they are not part of the Internet Protocol set (Internet Protocol Suite). They are just tools that use TCP/IP, just like common TCP/IP Protocol set application protocols. Because protocol definitions are inconsistent and commercial-supported TCP/IP tools are widely used, these Protocols may be part of the Interconnection protocol set. The above lists some simple examples of services based on TCP/IP, but it contains some "Main" applications.

TCP: Provides connection between computer programs, checks and discards duplicate groups, completes datagram validation, traffic control, and network congestion.