Both OSI and TCP/IP are models which specifies how data is processed and flows from one node to another.
TCP/ IP model: **** A four layered model, each layer processes the data and passes on to the next one.
| # | Name | Protocol/ App |
|---|---|---|
| 4 | Application | HTTP, SMTP |
| 3 | Transport | TCP/UDP |
| 2 | Internet | MAC |
| 1 | Link | RJ45 |
OSI Model: A seven layered model, each layer processes the data and passes on to the next one.
| # | Name | Protocol/ App |
|---|---|---|
| 7 | Application | HTTP, SMTP |
| 6 | Presentation | TLS |
| 5 | Session | SOCKS |
| 4 | Transport | TCP/ UDP |
| 3 | Network | IP routing |
| 2 | Data Link | MAC address |
| 1 | Physical | RJ45 etc. |
| TCP (Transfer Control Protocol) | UDP (User Datagram Protocol) |
|---|---|
| Reliable, acknowledgement is sent | Unreliable, no acknowledgement is sent |
| Re-transmission of packets in case | Re-transmission isn't available |
| Slow | Fast |
| Sequential | Non Sequential |
| Alice | Bob | |
|---|---|---|
| SYN | → | |
| ← | Syn, ACK | |
| ACK | → |
The handshake is followed by the communication which ends with FIN message.