FAQs - Networking and Storage Devices
General information and technical advice on IT networking devices including network switches, wireless access gateways and wireless access points and their use in LANs and WANs.
For networts the Open Systems Interconnection (OSI) model has seven layers that computer systems use to communicate over a network. Modern IT networks are based on the simpler TCP/IP model but OSI layers are still widely referred to, as the layering helps to visualise a network, isolate and resolve networking problems.
| Level | Layer | Description |
|---|---|---|
| 7 | Application | Human-computer interaction layer, where applications can access the network Services |
| 6 | Presentation | Ensures the data is in a usable format and is where data encryption occurs |
| 5 | Session | Maintains connections and is responsible for controlling ports and sessions |
| 4 | Transport | Transmits data using transmission protocols including TCP and UDP |
| 3 | Network | Decides which physical path the data will take |
| 2 | Data Link | Defines the format of the data on the network |
| 1 | Phsyical | Transmits raw bit stream over the physical medium |
According to Openreach super fast broadband is broadband offering speeds between 24Mbps and 300Mbp and is best for downloading, video calling and streaming TV and music on a regular basis.
A small office network, that mainly uses email and web browsing should have a bandwidth (the maximum rate of data transfer across a given network path) of 5-10 Mbps but for a larger office with more employees and users this would need to increase to at least 25 Mbps.