Packet structure
| Ethernet head | The length of 14 Byte |
| IPv4 first | The length of 20 + Byte |
| The TCP header | The length of 20 + Byte |
| User-defined application layer protocols | The length of the N Byte |
| Ethernet tail | The length of the 4 Byte |
OSI seven layer model
The Open System Interconnection Model
| Layers in the Internet protocol stack | Code | instructions |
|---|---|---|
| The physical layer | physical layer | Transmit data frames over a local area network. Examples are modems, radio, fiber optics |
| Data link layer | data link layer | Data link headers (DLH) are methods that contain physical addresses and error detection and correction. Such as Ethernet, token ring, HDLC, Frame Relay, ISDN, ATM, IEEE 802.11, FDDI, PPP |
| The network layer | network layer | The network header (NH) determines the path selection and forwarding of data. For example, IP, ICMP, IPX, BGP, OSPF, RIP, IGRP, EIGRP, ARP, RARP, and X.25 |
| The transport layer | transport layer | The transport header (TH) contains the protocol used to send information. For example, TCP, UDP, RTP, SCTP, SPX, ATP, and IL |
| The session layer | session layer | To set up and maintain communication connections between two computers in a computer network in data transfer. For example, ASAP, ISO 8327 / CCITT X.225, RPC, NetBIOS, Winsock, BSD Sockets, SOCKS, and password authentication protocol |
| The presentation layer | presentation layer | To convert data into a format compatible with the receiver’s system format and suitable for transmission. For example, JPEG, ASCII, UTF-8 |
| The application layer | application layer | Provides interfaces for application software. For example, HTTP, SMTP, SNMP, FTP, Telnet, SIP, SSH, NFS, RTSP, XMPP, Whois, ENRP, and TLS |