Chapter 6 OSI

Question 1

Layer 1: Physical Layer

Answer 1

Hubs operate at this layer

Paces network data on the wire

Changes binary data into electrical pulses on physical medium

Physical topology defined at this level

Decides if data travels unidirectionally or bidirectionally

Question 2

Layer 2: Data Link Layer

Answer 2

Bridges and Switches operate at this layer

Responsible for logical topology and logical MAC addressing

Individual network card addresses function at this level

Arranges data into “frames” that contain control information indicating beginning and end of datastream

allows for data checking within frames

Describes unique MAC address for each NIC

Divided into Media access control section and logical link control section

Question 3

Layer 3: Network Layer

Answer 3

Routers operate at this layer

Provides logical network addressing.

Data organized into packets

Judge best network path for data based on network conditions and priority

Manages traffic through packet switching, routing, and controlling congestion of data

Some error control and flow controle performed

Question 4

Layer 4: Transport Layer

Answer 4

Provides end to end communications.

Includes most of error and flow control

Contans TCP and UDP protocol

TCP verifies that destination host has recieved all packets

Question 5

Layer 5: Session layer

Answer 5

Establishes and maintains communications sessions

Session is one virtual conversation (eg. all proceedures needed to transfer a single file)

Enables network proceedures like identifying passwords, logons, and network monitoring

Question 6

Layer 6: Presentation Layer

Answer 6

Determines look and format of data

Performs protocol conversion and data compression, data translation, and encryption

Character set determined (which numbers represent which alphanumeric characters)

Question 7

Layer 7: Application Layer

Answer 7

Responsible for providing network services, file share, print services, messaging services