OSI Model Layer 1 Physical

Layer 1 Physical:

This layer is used to establish or terminate a connection to a communication medium.


 The characteristics of Layer 1 are:

  • It defines the electrical and mechanical specifications like cables, connectors, and signaling options of the medium.

Converters from one media to another operate at this level.

  • The primary differentiators would be, the cost-effectiveness of installation, performance, convenience, and maintenance. It defines the cable or physical medium such as thinnet, thicknet, unshielded twisted pairs (UTP).

A Hub is a physical layer device that has a very limited number of ports. When a frame reaches from a source to the hub port it will broadcast to all ports including the source port which leads to a single broadcast.

Hub function as a half-duplex when a simultaneous data transfer (send and receive)occurs on the same port. There is a greater possibility of a collision occurring in the hub environment.

  • Half-duplex: This means that data transmission is in a single direction at any given time, as a single wire pair enables only a one -way communication.

This would lead to a collision.

Full-duplex: This means that data transmission happens in two directions simultaneously as two-wire pairs support two-way communication.

TIP: All media provide similar functions.

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