1.2 OSI Layers

Question	Answer
OSI Model	A model for understanding and developing computer-to-computer communication, it divides networking functions among seven layers: 1.Physical, 2.Data Link, 3.Network, 4.Transport, 5.Session, 6.Presentation, and 7.Application.
Layer 1	Physical layer - responsible for taking 1s and 0s and encoding them into a digital signal for transmission on the network segment. - Hubs and repeaters see only bits
Layer 2	Data Link - provides framing and placing of data on the network medium. - switches and bridges understand and make decisions based on Layer 2 addresses
Layer 3	Network Layer - Provides logical network addressing and routing through an internetwork - Routers deal with Layer 3 addresses
Layer 4	Transport Layer - Provides segmentation, sequencing, and virtual circuits.
Layer 5	Session Layer - upper layer - responsible for communicating from a user interface to an application
Layer 6	Presentation
Layer 7	Application

Resource summary

	Created by Edvin Milkunic almost 6 years ago