IPv4 is a widely used 32-bit connectionless Internet Protocol that facilitates data communication across networks, utilizing a datagram header with various fields for addressing, fragmentation, and error checking.

The IPv4 packet header consists of 14 fields, of which 13 are required. The 14th field is optional and aptly named: options. The fields in the header are packed with the most significant byte first ( network byte order ), and for the diagram and discussion, the most significant bits are considered to come first ( MSB 0 bit numbering ).

This is a list of the IP protocol numbers found in the field Protocol of the IPv4 header and the Next Header field of the IPv6 header. It is an identifier for the encapsulated protocol and determines the layout of the data that immediately follows the header. Both fields are eight bits wide.

2025年1月15日 · This tutorial explains the IPv4 header in detail. Learn what an IPv4 header is, how many fields an IPv4 header contains, what the meaning of each field is, and what the value is stored in each field.

A set of cheetsheets for Ethernet, IPv4, UDP, TCP and ICMP protocol headers. An ethernet frame has a minimum size of 64 bytes and a maximum size of 1,518 bytes. Any frames smaller than the 64 byte minimum is interpreted by receivers as a collision. The Ethernet frame payload may not exceed 1,500 bytes.

This lesson explains the different fields in the IPv4 packet header like the version, header length, type of service, total length, etc.

The IHL field represents the total IPv4 Header Length, in 32-bit words; an IPv4 header can thus be at most 15 words long. The base header takes up five words, so the IPv4 Options can consist of at most ten words.

The IPv4 datagram is conceptually divided into two pieces: the header and the payload. The header contains addressing and control fields, while the payload carries the actual data to be sent over the internetwork.

2019年8月5日 · IPv4 headers consist of 32 8-bit bytes, known as octets. Each octet is a single 8-bit byte. There are 256 bits in total that make up the packet header. The chart below breaks down the structure of an IPv4 packet header into octets, bytes, bits, and bit offsets.

2024年6月27日 · IP Header is meta information at the beginning of an IP packet. It displays information such as the IP version, the packet’s length, the source, and the destination. IPV4 header format is 20 to 60 bytes in length. It contains information need for routing and delivery.