Chapter 3-1. Structure of the IP Header
Recommended reading: 【Information and Communication Network Technology】 Chapter 3. Communication Protocol
1. Version
○ 4 bits
2. Header Length
○ 4 bits
○ The header length ranges from a minimum of 20 bytes to a maximum of 60 bytes
3. TOS (Type of Service)
○ 8 bits
○ Subdivided into 3 bits of Precedence indicating priority, 4 bits of service type designation field, and 1 unused bit
4. Total Length
○ 16 bits
5. Identification
○ 16 bits
○ A unique number assigned to each generated packet
6. Flags
○ 3 bits
○ A field used to indicate whether the IP packet can be fragmented and whether it is the last fragment or not
7. Fragment Offset
○ 13 bits
○ When one packet is divided into multiple fragments, this field specifies the position of each fragment’s payload relative to the payload in the original packet
8. TTL (Time-to-Live)
○ 8 bits
○ Lifetime of the packet
9. Protocol
○ 8 bits
10. Header Checksum
○ 16 bits
○ A field for checking whether there are errors in the IP header
11. Source IP Address
○ 32 bits
12. Destination IP Address
○ 32 bits
13. Options
○ A field that defines the operation options of the IP protocol
14. Data
Entered: 2018.10.23 23:42