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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.
The common header, which occupies the first 12 bytes. In the adjacent diagram, this header is highlighted in blue. The data chunks, which form the remaining portion of the packet. In the diagram, the first chunk is highlighted in green and the last of N chunks (Chunk N) is highlighted in red. There are several types, including payload data and ...
A 16-bit field set to a value of 0x8100 [b] in order to identify the frame as an IEEE 802.1Q-tagged frame. This field is located at the same position as the EtherType field in untagged frames, and is thus used to distinguish the frame from untagged frames. Tag control information (TCI) A 16-bit field containing the following sub-fields:
The header contains information about IP version, source IP address, destination IP address, time-to-live, etc. The payload of an IP packet is typically a datagram or segment of the higher-level transport layer protocol, but may be data for an internet layer (e.g., ICMP or ICMPv6 ) or link layer (e.g., OSPF ) instead.
The first header field in an IP packet is the Version field. For IPv4, this is always equal to 4. Internet Header Length (IHL): 4 bits The IPv4 header is variable in size due to the optional 14th field (Options). The IHL field contains the size of the IPv4 header; it has 4 bits that specify the number of 32-bit words in the header.
Checksum is the 16-bit ones' complement of the ones' complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets. [7] In other words, all 16-bit words are summed using ones' complement arithmetic. Add the 16-bit values up.
IPv4 header 20 byte: TCP header 20 byte: 8960 byte: 9038 byte: 99.14% Other frame sizes for reference IEEE 802.11 on A-MSDU [15] [16] 7935: PLCP preamble & header 24 byte: IPG varies: frame header & security ovhd 52 byte: FCS 4 byte: IPv4 header 20 byte: TCP header 20 byte: 7895 byte: 8015 byte + IPG size < 98.5% IEEE 802.11 bridged to standard ...
In the IPv4 header, TTL is the 9th octet of 20. In the IPv6 header, it is the 8th octet of 40. The maximum TTL value is 255, the maximum value of a single octet. A recommended initial value is 64. [2] [3] The time-to-live value can be thought of as an upper bound on the time that an IP datagram can exist in an Internet system.