C172 Network and Security Foundations

Which layer of the OSI model establishes, manages, and terminates connections? A. Session B. Application C. Presentation D. Network

A. Session

Layer 7

Application Layer

Which layer of the OSI model does a bridge use to make decisions about forwarding data packets? A. Network B. Physical C. Data Link D. Transport

C. Data Link

Which device is used to connect host devices within a local area network? A. Gateway B. Repeater C. Switch D. Router

C. Switch

Which device operates at layer 2 of the OSI model? A. Hub B. Repeater C. Switch D. Router

C. Switch

Which TCP/IP layer performs addressing and routing? A. Application B. Transport C. Presentation D. Network

D. Network

Layer 2

Data Link Layer

Layer 3

Network Layer

Layer 1

Physical Layer

Layer 6

Presentation Layer

Layer 5

Session Layer

Session Layer

The fifth layer in the OSI model. This layer establishes and maintains communication between two nodes on the network. It can be considered the "traffic cop" for network communications.

Transport Layer

The fourth layer of the OSI model. In this layer protocols ensure that data are transferred from point A to point B reliably and without errors. this layer services include flow control, acknowledgment, error correction, segmentation, reassembly, and sequencing.

Physical Layer

The lowest, or first, layer of the OSI model. Protocols in this layer generate and detect signals so as to transmit and receive data over a network medium. These protocols also set the data transmission rate and monitor data error rates, but do not provide error correction.

Data Link Layer

The second layer in the OSI model. This layer bridges the networking media with the Network layer. Its primary function is to divide the data it receives from the Network layer into frames that can then be transmitted by the Physical layer.

OSI Model

The seven layers describing network functions

Application Layer

The seventh layer of the OSI model. Application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network.

Presentation Layer

The sixth layer of the OSI model. Protocols in the Presentation layer translate between the application and the network. Here, data are formatted in a schema that the network can understand, with the format varying according to the type of network used. The Presentation layer also manages data encryption and decryption, such as the scrambling of system passwords.

Network Layer

The third layer in the OSI model. Protocols in this layer translate network addresses into their physical counterparts and decide how to route data from the sender to the receiver.

Layer 4

Transport Layer