Network+ Module 1 Networking Overview

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.

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

A. Packet Explanation: When information arrives at the Network Layer (layer 3) it includes logical addressing added to it such as the source and destination IP address. However, it can also be called a datagram if its a connection-less transmission.

This type of device uses IP addresses to determine where to send network traffic. A. Router B. Hub C. WAP D. Server

A. Router Explanation: Routers make decisions to send traffic from one network to another based on the destination IP address in the IP packet. The IP address of a host determines which network it belongs to and using this information the router can determine which local interface or neighboring router to route the traffic to.

This type of device serves as the gateway (aka default gateway) for IP traffic to leave the LAN. A. Router B. Hub C. WAP D. Server

A. Router Explanation: The device that a host must send traffic to for leaving the local LAN and talking to another network is referred to as a gateway or a default gateway. Since routers are the devices that are capable of sending traffic from one network to another network they are also the default gateway for a LAN.

The protocol data unit for the top 3 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 the Application Layer respectively. These layers all have the same PDU which is simply called data.

An Ethernet Hub is physically a star, but logically a bus. A. True B. False

A. True Explanation: A hub provides a central point that other devices physically connect to creating the focal point of a physical Star topology. However, inside of the hub the connections are wired in such a way that all the ports on the hub are connected to the same internal wire or cable. Because of this design the inner workings and logical flow of data through a hub represent a bus topology while the way that devices physically connect to the hub represent a Star topology.

Remote sharing applications use protocols such as BitTorrent to create Peer-to-Peer network among other computers running the same software. A. True B. False

A. True Explanation: BitTorrent is an example of a Peer-to-Peer (P2P) file sharing protocol which allows any computer with the BitTorrent capable software installed to join the Peer-to-Peer network and share files with the other peers (even over the internet). These types of applications are regarded as highly unsafe for use in corporate networks due to their capacity for transmitting malware and distributing company data into the public domain without the user's knowledge.

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 correespond to multiple layers of the OSI Model. Layer 1 of the TCP/IP Model 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 corresponds to Layers 5-7 of the OSI Model.

The Star topology is the most common type of topology and has a single, centralized point of failure. A. True B. False

A. True Explanation: The simplest example of a physical Star topology is a centralized hub or switch with other network nodes all connected to it. In this way, we can visualize that the centralized hub or switch is the single focal point of the Star topology and if it were to fail none of the devices connected to it would have access to the network.

This type of device provides a client with network access over wireless media. A. Wireless Access Point B. Hub C. Wired Access Point D. Switch

A. Wireless Access Point Explanation: Wireless Access Points, also known as WAP, APs, Access Points, or Wireless Aps, are the devices that wireless hosts connect to for access to the network

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 medim it is performed by signaling a series of ons and offs similar to a flash light turning on and off again in repetition. These ons 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 its at the physical layer of the OSI Model (layer 1)

Peer-to-Peer networks have a dedicated, centralized server for clients to connect to. A. True B. False

B. False Explanation: In Peer-to-Peer networks all hosts can act as both a client and a server, so there is no dedicated or centralized single server for the clients to connect to. Instead, the hosts are all peers to one another and connect to each other to access services and resources.

Modern networks must be based on either Client/Server or Peer-to-Peer, but never both. A. True B. False

B. False Explanation: In modern networks both the Client/Server and Peer-to-Peer models are used. Some network services and applications require a dedicated and centralized network, while other services and resources can be accessed directly from other hosts (peers) on the network

A physical topology defines how data flows through a network rather than how devices are physically connected to one another. A. True B. False

B. False Explanation: Logical topologies represet how data flows, while physical topologies represent the physical connections between devices

Hubs should be used instead of switches because hubs provide for better network performance than switches. A. True B. False

B. False Explanation: Switches provide much better performance than that of hubs and should always be used instead of hubs. Hubs can still be used, but rarely seen in larger enterprise networks due to their poor performance in comparison with switches.

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 the cables and media are referenced in the OSI Model. The Data Link Layer is where devices sch as Switches operate.

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

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

A network topology such as a Star, Bus or Ring can be used to represent either a logical or physical topology, but can't be used to represent both. A. True B. False

B. False Explanation: The types of network topologies can be used to represent the way devices are physically interconnected and/or how data logically flows through the network. For example, the Bus topology can be used to represent the way that devices are both physically and logically connected in the days of early Ethernet. In the same sense the Bus topology can represent how data logically flows through a modern Ethernet hub which is a physical star topology, but a logical bus topology. With an ethernet switch the topology is both a physical and logical star, so here we can see that the different types of topologies can be used to represent both physical and logical scenarios.

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 ______________. 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 2 names. It can be either called the Network Interface Layer or the Link Layer

Switches make intelligent switching decisions by learning which devices are connected to them. Which of the following types of addresses does a switch learn about from connected hosts? A. Layer 3 Address B. MAC Address C. Unicast Address D. IP Address

B. MAC Address Explanation: Switches learn the MAC address of connected hosts and keep them stored in the MAC address table

The physical connections between network devices, either wired or wireless, are known as the network_________. A. Access B. Media C. Hub D. Cable

B. Media Explanation: The connections between devices are collectively referred to as network media and individually referred to as a network medium.

This type of physical topology was used in the early days of Ethernet and if there was a break anywhere in the cable it would cause the entire Ethernet segment to go down. A. Ring B. Mesh C. Bus D. Star

C. Bus Explanation: Early Ethernet (ThickNet and THinNet) connected workstations to the network via coaxial cables that vampire tapped into a centralized and larger coaxial cable. In effect this creates a "one-cable" LAN where all workstations are connected in succession. This is a "bus" arrangement and all transmissions are received by every workstation on the network even if the transmission was destined for a single machine. An additional drawback is if a break happens in any part of the cable it causes the entire bus to break and all the hosts lose their connection to the network.

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 called a Segment.

This type of device can be local to the network or in a remote location and provides services to clients such as sharing of resources and files. A. Router B. Client C. Server D. Switch

C. Server Explanation: Servers are computers on networks that provide services to Clients. Servers can reside on the local network (such as local file servers) or on a remote network (such as web servers that host websites).

A network technician needs to connect a user's PC to the wired Ethernet Network, What is the BEST device the technician should use to connect the PC into the wired network? A. Server B. Hub C. Switch D. Wireless Access Point

C. Switch. Explanation: Switches and Hubs are used to connect wired nodes to the network. Switches are for intelligent devices that learn MAC addresses and have better performance than hubs. Therefore a switch should always be used as the best option over hubs.

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 an 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.

This type of device is a workstation used by an end user which provides the user with access to the network. A. Switch B. LAN C. WAN D. Client

D. Client Explanation: The hosts or end-user devices on a network are referred to as Clients

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.

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 which contains functionality such as routing, protocols such as IP, and devices such as routers.

A single Ethernet Switch creates a topology that is both logically and physically this type... A. Ring B. Mesh C. Bus D. Star

D. Star Explanation: The way devices physically connect to an Ethernet switch represents a Star topology, which is the same as a hub. However, the way data flows through a switch is much different than a hub which is logically a bus. In a switch each port has its own dedicated connection into the switching circuitry, so the way the data flows through a switch is the same as the way it is connected physically. In this way an Ethernet switch is both a logical Star and a physical Star.