COMPTIA Network+ (N10-008)

Which network device operates at layer 2? -Repeater -Switch -Router -Firewall

A basic switch operates at layer 2 of the OSI model. For the exam, unless they mention a "multilayer switch" or "layer 3 switch", always assume they are referencing a basic layer 2 switch. A router is a layer 3 device. A repeater is a layer 1 device. A firewall will operate layers 3 through 7, depending on the type of firewall.

Which type of network device operates at layer 1 of the OSI model and requires connected devices to operate at half-duplex using CSMA/CD?

A hub is a network hardware device for connecting multiple Ethernet devices together and making them act as a single network segment. A hub operates at the physical layer (Layer 1) of the OSI model. All devices connected by a hub are in a single collision domain and a single broadcast domain, therefore they must use half-duplex for communication and CSMA/CD.

Which of the following applies to data as it travels from Layer 1 to Layer 7 of the OSI model? -Tagging -Encapsulation -Tunneling -De-encapsulation

Data encapsulation and de-encapsulation in a computer network is a necessary process. De-encapsulation in networking is performed at the receiver side or destination side as data moves from layer 1 to layer 7 of the OSI model. As information travels up the layers of the OSI layer, information added from the sender's encapsulation process is removed layer by layer.

Define Media

Material used to transmit data over the network.

According to the OSI model, at which of the following layers is data encapsulated into a frame? -Layer 1 -Layer 2 -Layer 3 -Layer 4

The data layer, or layer 2, is the second layer of the seven-layer OSI model. The data link layer encapsulates data into frames for delivery between nodes on the same network. Data is transmitted at Layers 5, 6, and 7 of the OSI model. At Layer 4, the data is encapsulated into segments. At layer 3, the segments are encapsulated into packets. At layer 2, the packets are encapsulated into frames. At layer 1, the frames are encapsulated into bits.

What layer of the OSI model is responsible for data encryption and character set conversion, such as ASCII to UTF-8? -Layer 7 -Layer 6 -Layer 5 -Layer4

The presentation layer (layer 6) establishes the way in which information is presented, typically for display or printing. Data encryption and character set conversion (such as ASCII to EBCDIC) are usually associated with this layer. The presentation layer translates information in a way that the application layer understands. This layer also translates information from the application layer to the session layer.

Benefits of Client/Server

■ Centralized administration ■ Easier management ■ Better scalability

Network Resources

■ Client/Server Model ■ Peer-to-Peer

Media

■ Connect two devices or a device to a port ■ Made from copper cable, fiber optic cable, or radio frequency waves (WiFi) ■ Each type has strengths and limitations, such as its available bandwidth, capacity, distance that can be covered, and cost to install and maintain

Router

■ Connect two different networks together ■ Intelligently forwards traffic to and from a network based on its logical address ■ Most modern routers use Internet Protocol (IP) address to determine routing of traffic

Switch

■ Connects networked devices such as clients and servers (like a hub) ■ Switches learn what devices are on which switch ports ■ Switches only forward traffic received from a port to the destination port based on the device's MAC address ■ Provides more security and efficiently uses available bandwidth

Drawbacks to Peer-to-Peer

■ Decentralized management ■ Inefficient for large networks ■ Poor scalability

Client

■ Device end-user accesses the network with ■ Workstation, laptop, tablet, smartphone, television, server, or other terminal devices ■ Can be any device that connects to the network

Wireless Access Point (WAP)

■ Device that allows wireless devices to connect into a wired network ■ Commonly used in home, small business, and even some large enterprise networks ■ Acts as a wireless hub

Coaxial Connectors

■ F-connector ● Typically used for cable TV and cable modem connections ■ BNC ● Termed Bayonet Neill-Concelman or British Naval Connector ● Was used for 10BASE2 Ethernet networks

Drawbacks of Client/Server

■ Higher cost ■ Requires dedicated resources ■ Requires network operating system

Coaxial Cable (Coax)

■ Inner ● Insulated conductor or center wire passes data ■ Outer ● Braided metal shield used to help shield and protect the data transmission ● Provides EMI resistance due to shielding

Benefits of Peer-to-Peer

■ Lower cost ■ No dedicated resources required ■ No specialized operating system required

Hub

■ Older technology to connect networked devices, such as clients and servers ■ Can be interconnected to provide more ports, but leads to increased network errors ■ Receives information in one port and rebroadcasts it out all the other ports

Peer-to-Peer Model

■ Peers (PCs) share resources (files/printers) with each other directly ■ Administration and backup are more difficult since resources are located on a many PCs which adds to the administrative burden

Network Geography

■ Personal Area Network (PAN) ■ Local Area Network (LAN) ■ Campus Area Network (CAN) ■ Metropolitan Area Network (MAN) ■ Wide Area Network (WAN)

Wide Area Network (WAN) Link

■ Physically connects networks together (geographically dispersed - i.e. the internet is a series of WAN Links) ■ Numerous WAN links are available ● Leased lines ● DSL ● Cable ● Fiber Optic ● Satellite ● Cellular ● Microwave ■ Connects internal network to external networks, such as a SOHO network to Internet

Server

■ Provides resources to the rest of the network ■ Different servers provide different functions, such as an E-mail server, Web server, File server, Chat server, and Print server ■ Can be a dedicated server hardware/software or can be a device that is acting like a server for a particular function

Coaxial Cables

■ RG-6 ● Commonly used by local cable companies to connect individual homes ■ RG-59 ● Typically used to carry composite video between two nearby devices, such as from a cable box to the television

Twinaxial Cable

■ Similar to coaxial cable but uses two inner conductors to carry the data instead of just one

Client/Server Model

■ Uses dedicated server to provide access to files, scanners, printers, and other resources ■ Administration and backup are easier since resources are located on a few key servers

Serial Cable

■ Usually have a series of straight copper wires inside a single cable or plastic jacket ■ DB-9 or DB-25 (RS-232) ● 9-pin or 25-pin D-subminiature ● Used for asynchronous serial communications and connecting to an external modem

Types of Media

■Three categories ● Copper ● Fiber optic ● Wireless ■ Each category is divided into subcategories ■ Each has different specifications and uses