OSI: The Reference Model
The Open Systems Interconnect model (OSI Model) explains all the individual functions that are necessary for the Internet to work.
Last updated
The Open Systems Interconnect model (OSI Model) explains all the individual functions that are necessary for the Internet to work.
Last updated
The OSI model is divided into seven layers, each fulfilling a particular function. When combined, each function contributes to enabling full computer-to-computer data communication.
The Physical layer of the OSI model is responsible for the transfer of bits — the 1’s and 0’s which make up all computer code.
Simply put, Layer 1 is anything that carries 1’s and 0’s between two nodes.
The actual format of data on the "wire" varies depending on the medium. For Ethernet, bits are transferred as electric pulses; for WiFi, as radio waves; and for Fiber, as pulses of light.
Apart from the physical cable, Repeaters and Hubs also operate at this layer.
A Repeater simply repeats a signal from one medium to another, allowing a series of cables to be daisy-chained together and extending the distance a signal can travel beyond the limit of a single cable. They are commonly used in large WiFi deployments, where a single WiFi network is "repeated" across multiple access points to cover a larger area.
A Hub is essentially a multi-port Repeater. When four devices are connected to a single Hub, any data sent by one device is repeated to the other three devices.
