OSI model and topologies - Dleifnesor/NET-150 GitHub Wiki

OSI model - Open system interconnect

1. Physical Signals and media NICs, twisted-pair cable, fiber
2. Data link Provides for the flow of data MAC addresses
3. Network Provides routing decisions IP, IPX
4. Transport Ensures error-free packets TCP, UDP
5. Session Establishes, manages, and terminates sessions NFS, SQL6. Presentation Protocol conversion, data translation ASCII, JPEG
6. Application Support for applications HTTP, FTP, SMTP (email)

The star network config is the most common network topology, as it minimizes both the cabling costs, and offers less chance of errors like from Bus topology

bus topology suffers from the possibility of simultaneous transmissions resulting in errors / packet loss

Mesh networks have the benefit of full redundancy as every networking device is connected to every other network device with its own cabling, this is good for applications that require full redundancy however it can be too costly for general networking applications as it exponentially increases set up time and networking hardware cost (office spaces).