Analysis of TCP/IP Model

Analysis of TCP/IP Model 1. TCP/IP Protocol Introduction TCP/IP (also known as TCP/IP protocol cluster) is a group of communication protocols used to achieve network interconnection, the name is derived from two important protocols (IP protocol and TCP protocol) in the protocol cluster ). Based on the TCP/IP reference model, the protocols are divided into four layers: network interface layer, Internet connection layer (IP layer), transmission layer (TCP layer), and application layer. The TCP/IP model and the comparison between the model and the OSI model are illustrated. Www.2cto.com
Figure OSI model and TCP/IP model comparison figure ① network interface layer: the network interface layer corresponds to the physical layer and data link layer in the OSI reference model. ② Internet layer: the Internet layer corresponds to the network layer of the OSI reference model, which mainly solves the communication problem between the host and the host. The layer has four main Protocols: Internet Protocol (IP), Address Resolution Protocol (ARP), Internet Group Management Protocol (IGMP) and Internet Control Packet Protocol (ICMP ). The IP protocol is the most important protocol in the Internet layer. It provides an unreliable, connectionless datagram transmission service. ③ Transport layer: the transport layer corresponds to the transport layer of the OSI reference model, providing end-to-end communication for the application layer entities. This layer defines two main Protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP ). TCP provides a reliable connection-oriented data transmission service, while UDP provides unreliable and connectionless data transmission services. ④ Application layer: the application layer corresponds to the Session Layer, presentation layer, and application layer of the OSI reference model, providing users with various services, such as FTP, Telnet, DNS, and SMTP. Www.2cto.com 2. comparison between the OSI model and the TCP/IP model (1) Comparison between the OSI model and the TCP/IP model shows that the OSI model introduces the concepts of services, interfaces, protocols, and layers, TCP/IP models are built based on these OSI concepts. OSI has a model, followed by a protocol, followed by a standard, followed by practice; while TCP/IP has the opposite, a model is first proposed based on the protocol and application, and is a reference OSI model. OSI is too complex. TCP/IP is simple but not comprehensive. OSI has been standardized for a long time. At the same time, TCP/IP has been widely used and has become a de facto standard for network interconnection. (2) the OSI model and the TCP/IP model list the Protocol Comparison and protocol description between the OSI model and the TCP/IP model. Table OSI model and TCP/IP Model Protocol Comparison Table layer www.2cto.com in OSI function TCP/IP protocol cluster application layer file transfer, email, file service, data formatting and code conversion on the TFTP, HTTP, SNMP, FTP, SMTP, DNS, and Telnet presentation layers of virtual terminals, data Encryption does not enable the Protocol Session Layer to terminate or establish contact with other contacts. No protocol Transport Layer provides end-to-end interfaces. TCP and UDP network layer select the Route IP, ICMP, OSPF, BGP, IGMP, ARP and RARP data link layer transmit address frames and Error Detection Functions SLIP, PPP, and MTU physical layer transmit data in the form of binary data on physical media ISO2110, IEEE802, 802.2 www.2cto.com 3. the TCP/IP communication process diagram shows the communication process between two hosts over the TCP/IP protocol. The application layer uses the FTP protocol. Except that the physical layer actually transmits data, other peer layers only perform virtual communication (so the dotted line is drawn), and the peer layer generally follows the same protocol. The data transmitted over the upper layer is only related to the adjacent upper and lower layers. The TCP layer and the following layers are implemented by the operating system kernel to handle communication details. The Application Layer program is implemented through socket programming and processes application details.

Figure 4. TCP/IP packet description. The IP layer transmission unit is an IP group, which belongs to point-to-point transmission. The TCP layer transmission unit is a TCP segment and belongs to End-to-End transmission.

Figure TCP/IP packet description