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📜  OSI与TCP / IP

📅  最后修改于: 2020-11-10 04:42:43             🧑  作者: Mango

OSI与TCP / IP

什么是OSI模型?

OSI代表于1980年代开发的开放系统互连。它是用于网络通信的概念模型。它没有完全实现，但今天仍然引用。该OSI模型由七个层组成，并且每个层相互连接。数据在OSI模型中向下移动，并且每一层都添加了附加信息。数据向下移动，直到到达OSI模型的最后一层。当在OSI模型的最后一层接收到数据时，数据将通过网络传输。一旦在另一侧到达数据，该过程将被逆转。

什么是TCP / IP模型?

TCP模型代表传输控制协议，而IP代表互联网协议。 TCP / IP模式下可能有许多使互联网成为可能的协议。如今，我们很少听到TCP / IP模型的名称，我们通常听到的是IPv4或IPv6的名称，但是它仍然有效。该模型包括4层。现在，我们将看一下TCP / IP模型的图形表示。

如上图所示，TCP / IP模型具有4层，而OSI模型则由7层组成。从图中可以看出，TCP / IP模型的4层完全适合OSI模型的7层，但这不是事实。 TCP / IP模型的应用程序层映射到前三层，即OSI模型的应用程序，会话和表示层。 TCP的传输层直接映射到OSI模型的传输层。 TCP / IP模型的Internet层直接映射到OSI模型的网络层。 OSI模型的最后两层映射到TCP / IP模型的网络层。与OSI模型相比，TCP / IP是最广泛使用的模型，用于通过Internet提供计算机之间的通信。

OSI和TCP / IP模型之间的相似之处

以下是OSI和TCP / IP模型之间的相似之处：

  • 共享通用架构

这两个模型都是逻辑模型，并且具有相似的体系结构，因为这两个模型都是使用层构建的。

  • 定义标准

这两层都定义了标准，并且它们还提供了用于实现标准和设备的框架。

  • 简化故障排除流程

两种型号都将复杂的函数分解为更简单的组件，从而简化了故障排除过程。

  • 预定义标准

已经预先定义的标准和协议；这些模型没有重新定义它们；他们只是引用或使用它们。例如，在开发这些模型之前，IEEE已经定义了以太网标准。模型没有重新创建它们，而是使用了这些预定义的标准。

  • 两者具有“传输”和“网络”层的相似功能

其在“呈现”和“网络”层之间执行的函数类似于在传输层执行的函数。

OSI和TCP / IP模型之间的差异

让我们以表格形式查看OSI和TCP / IP模型之间的区别：

OSI Model TCP/IP Model
It stands for Open System Interconnection. It stands for Transmission Control Protocol.
OSI model has been developed by ISO (International Standard Organization). It was developed by ARPANET (Advanced Research Project Agency Network).
It is an independent standard and generic protocol used as a communication gateway between the network and the end user. It consists of standard protocols that lead to the development of an internet. It is a communication protocol that provides the connection among the hosts.
In the OSI model, the transport layer provides a guarantee for the delivery of the packets. The transport layer does not provide the surety for the delivery of packets. But still, we can say that it is a reliable model.
This model is based on a vertical approach. This model is based on a horizontal approach.
In this model, the session and presentation layers are separated, i.e., both the layers are different. In this model, the session and presentation layer are not different layers. Both layers are included in the application layer.
It is also known as a reference model through which various networks are built. For example, the TCP/IP model is built from the OSI model. It is also referred to as a guidance tool. It is an implemented model of an OSI model.
In this model, the network layer provides both connection-oriented and connectionless service. The network layer provides only connectionless service.
Protocols in the OSI model are hidden and can be easily replaced when the technology changes. In this model, the protocol cannot be easily replaced.
It consists of 7 layers. It consists of 4 layers.
OSI model defines the services, protocols, and interfaces as well as provides a proper distinction between them. It is protocol independent. In the TCP/IP model, services, protocols, and interfaces are not properly separated. It is protocol dependent.
The usage of this model is very low. This model is highly used.
It provides standardization to the devices like router, motherboard, switches, and other hardware devices. It does not provide the standardization to the devices. It provides a connection between various computers.