Network+ - Networking Models

This layer of the OSI Model is a reference point for IP routing and routers. A. Network B. Data Link C. Transport D. Presentation

A. Network Explanation: The Network Layer is layer 3 which references logical addressing and the protocols and devices (such as routers) that make it possible to route traffic from one network to another network.

The protocol data unit for the top three layers of the OSI Model (layers 5 - 7) is the same. A. True B. False

A. True Explanation: Layer 5 - 7 of the OSI Model are the Session Layer, Presentation Layer and Application Layer respectively. These layers all have the same PDU which is simply called Data.

The TCP/IP Model is a representation of the TCP/IP stack of protocols. A. True B. False

A. True Explanation: The TCP/IP Model represents the TCP/IP stack of protocols that already exist.

The TCP/IP Network Interface Layer (aka Link Layer) corresponds to the OSI Model Physical and Data Link Layers. A. True B. False

A. True Explanation: The layers of the TCP/IP Model correspond to certain layers of the OSI model. Since there are only 4 layers in the TCP/IP Model some of them will correspond to multiple layers of the OSI Model. Layer 1 of TCP/IP corresponds to Layers 1 and 2 of the OSI Model. Layer 2 of the TCP/IP Model corresponds directly to Layer 3 of the OSI Model. Layer 3 of the TCP/IP Model corresponds directly to layer 4 of the OSI Model. Layer 4 of the TCP/IP Model corresponds to Layers 5 - 7 of the OSI Model.

What is the protocol data unit (PDU) at layer 1 of the OSI model? A. Transport B. Bits C. Segment D. Data

B. Bits Explanation: When information is ready to be placed onto the wired or wireless transmission medium it is performed by signaling a series of ones and offs similar to a flashlight turning on and then off again in repetition. These ones and offs equate to ones and zeros in the world of computing and are called bits. This is the reason why we call the information bits when is it at the Physical Layer of the OSI Model (layer 1).

Network media such as cables and connectors reside on the Data Link Layer of the OSI Model. A. True B. False

B. False Explanation: The Physical Layer (layer 1) is where all cables and media are referenced in the OSI Model. The Data Link Layer is where devices such as Switches operate.

The TCP/IP Model includes 7 layers. A. True B. False

B. False Explanation: The TCP/IP Model has only 4 layers while the OSI Model has 7 layers

Which layer is the Data Link Layer of the OSI Model? A. Layer 3 B. Layer 2 C. Layer 6 D. Layer 1

B. Layer 2 Explanation: The Data Link Layer is the layer just above the Physical Layer (layer 1). The Data Links Layer is layer 2 which contains the MAC and LLC sub-layers and is where switches and MAC addresses reside.

The TCP/IP Network Interface Layer is also known as the ________________. A. Network Layer B. Link Layer C. Application Layer D. Transport Layer

B. Link Layer Explanation: Layer 1 of the TCP/IP Model technically has two names. It can be called either the Network Interface Layer or the Link Layer.

Layer 2 of the TCP/IP Model is known as the ______________ Layer. A. Network Interface B. Application C. Internet D. Transport

C. Internet Layer Explanation: The second layer of the TCP/IP Model is the Internet Layer which handles routing and the IP protocol

What is the protocol data unit (PDU) at layer 4 of the OSI model? A. Transport B. Bits C. Segment D. Data

C. Segment Explanation: When information arrives at the Transport Layer it includes port based information to define the protocol or application that the information is for. When information is referenced with a TCP port number it is called a Segment

A Host computer works at which layer(s) of the OSI Model. A. Layers 5-7 B. No layers C. Layers 1-4 D. All layers

D. All layers Explanation: Host computers run applications that access network resources. This is the entire reason why we need networks in the first place - so that an application on a computer can send data to an application on another computer. So, host computers work at the Application Layer and process information all the way down the OSI model encapsulating the Data into Segments, Packets, Frames, and then placing it onto the medium as bits via the network interface card.

What is the protocol data unit (PDU) at layer 2 of the OSI model? A. Packet B. Bits C. Data D. Frame

D. Frame Explanation: Frames represent encapsulation (the packaging of information) at the Data Link layer. The Frame is the last form of encapsulation before the information is placed onto the physical medium as ones and zeros.

What is the protocol data unit (PDU) at layer 3 of the OSI model? A. Packet B. Bits C. Data D. Segment

D. Frame Explanation: Frames represent encapsulation (the packaging of information) at the Data Link layer. The Frame is the last form of encapsulation before the information is placed onto the physical medium as ones and zeros.

TCP and UDP reside at this layer of the OSI Model. A. Layer 3 B. Layer 2 C. Layer 7 D. Layer 4

D. Layer 4 Explanation: Layer 4 of the OSI Model is the Transport Layer where TCP and UDP operate.

Which layer of the OSI Model is layer 3? A. Data Link B. Physical C. Presentation D. Network

D. Network Explanation: Layer 3 is the Network Layer that contains functionality such as routing, protocols such as IP, and devices such as routers.