User:CONFIQ/ccna
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I want to dispense my knowledge on progress called encapsulation.
Let's say we have some data on 7th layer of OSI model, or 5th layer of TCP/IP model, the data has been created! On Transport_layer data gets his first header and depending on application layer header should be send as UDP or TCP. This is example of UDP header:
| + | Bits 0 - 15 | 16 - 31 | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | Source Port | Destination Port | ||||||||||||||||||||||||||||||
| 32 | Length | Checksum | ||||||||||||||||||||||||||||||
| 64 | Data |
|||||||||||||||||||||||||||||||
more info on UDP. If it's TCP than header will look like this:
| Bit offset | Bits 0–3 | 4–7 | 8–15 | 16–31 | ||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | Source port | Destination port | ||||||||||||||||||||||||||||||
| 32 | Sequence number | |||||||||||||||||||||||||||||||
| 64 | Acknowledgment number | |||||||||||||||||||||||||||||||
| 96 | Data offset | Reserved | CWR | ECE | URG | ACK | PSH | RST | SYN | FIN | Window | |||||||||||||||||||||
| 128 | Checksum | Urgent pointer | ||||||||||||||||||||||||||||||
| 160 | Options (optional) | |||||||||||||||||||||||||||||||
| 160/192+ | Data |
|||||||||||||||||||||||||||||||
more info on TCP.
data that goes through Transport layer is called segments.
