Computer network model of "computer network"

The TCP/IP model is from low to High: Link layer, network layer, Transport layer, application layer.

Each layer is responsible for the different functions:

1) The link layer, sometimes referred to as the data link layer or the network interface layer, usually includes the device driver in the operating system and the network interface card corresponding to the computer. They work together with the physical interface details of the cable (or any other transmission medium).

2) Network layer: Responsible for routing and storage and forwarding of packets. The Protocols of the network layer are: ip,icmp,igmp,arp,rapr,ospf,ipx. The units of the network layer's data are called groupings or packets.

3) Transport layer: The Transport layer is the model from the bottom to the top of the first to provide end-to-end, that is, process-to-process hierarchy. The application layer uses the end-to-end (end-to-end) protocol with the transport layer. However, the network layer provides a hop-by-tick (hop-by-hop) protocol. Transport Layer protocols are: TCP, UDP, SCTP, and so on. The Unit of Transport layer data is called a message or data segment.

4) Application layer: The application layer provides an interface for the operating system or network application to access the Network service. The application layer protocols are:
Telnet (TCP-based, default port: 23)

FTP (TCP-based, default port, 21 (Control)/20 (data transfer))

HTTP (TCP-based, default port: 80)

Snmp

DNS (UDP-based)

Smtp

SSH (TCP-based, default port: 22)

The network architecture model provided by the International Organization for Standardization (ISO), known as the Open Systems Interconnect Reference Model (OSI/RM), is often referred to as the OSI Reference model. OSI has seven layers, from top to bottom the physical layer, Data link layer, network layer, transport layer, Session layer, presentation layer, application layer. However, due to the wide application of TCP/IP protocol model, the TCP/IP model has become the de facto international standard. The corresponding relationship between TCP/IP and the OSI Reference model is as follows:

OSI Reference Model	TCP/IP protocol	Each layer contains protocols	Equipment
Application Layer (application)	Application Layer	Http,snmp,ftp,smtp,dns,telnet,tftp
Presentation Layer (Presentation)
Conversation Layer (session)
Transport Layer (Transport)	Transport Layer	Tcp,udp,sctp
Networking Layer (Network)	Network layer	Ip,icmp,rip,ospf,bgp,igmp,arp,rarp	Routers, layer three switches
Data Link Layer	Link Layer		Bridge (less used), Ethernet switch (two-tier switch), NIC (half physical layer, half link layer)
Physical Layer (physical)			Repeater, Hub

Resources:

1. "Computer network-top-down Approach" (fourth edition) 1.5

2. "TCP/IP Detailed Volume 1: agreement" 1.2

3. http://www.ha97.com/3215.html

Computer network model of "computer network"