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Network
OSI Model
The OSI (Open System Interconnect) Model was developed in 1984 as an open standard to promote network interconnection and interoperability.
Layer | Function | Examples |
---|---|---|
7. Application | Support for applications | HTTP, FTP, SMTP (email) |
6. Presentation | Protocol conversion, structures data for the application | ASCII, JPEG, etc. |
5. Session | Establishes, manages and terminates sessions & connections | NFS, SQL |
4. Transport | Is concerned with message integrity between source and destination | TCP, UDP |
3. Network | Combines messages into packets, adding routing information | IP, IPX |
2. Data Link | Handles flow control, sequencing, errors | MAC |
1. Physical | Provides electrical and mechanical connections to the network | cables and NIC |