IPv4 Datagram Header Flashcards
Version
4 Bits. Indicates IP version being used
Header Length
4 Bit. Declares how long the header is
Service Type Field
8 bits. Specify details about QoS technologies
Total Length Field
16 bits. Indicates total length of the IP datagram its attached to
Identification Field
16 bits. Number that is used to group messages together
Flag Field
3 bits. Used to indicate if a datagram is allowed to be fragmented, or to indicate that the datagram has already been fragmented
Fragmentation Offset
Contains values to allow fragmented packets to be put back together in order
TTL
Time To Live. 8 bits. Indicates how many router hops a datagram can traverse before it’s thrown away
Protocol Field
8 bit. Contains data about what transport layer protocol is being used
Header Checksum Field
A checksum of the entire contents of the IP datagram header
Source IP Address
32 bits. Where the data is coming from
Destination IP Address
32 bits. Where the data is going
Options
Optional and variable length. Used to set special characteristics for datagrams primarily used for testing purposes
Padding
A series of zeros after/in place of the options field to make sure the header is the proper length
