Network+ Certification Exam Questions and Answers, Exams of Biology

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Peer-to-Peer Network - answer Individual hosts don't have a specific role. Hosts both provide and consume network resources Client-Server Network - answer Hosts have specific roles assigned to them In this case, some hosts may be assigned to be servers

LAN - answer When multiple networks within the same organization are connected together, it's a LAN MAN - answer When LANs within the same city are connected together, they form a MAN WAN - answer Many networks in many different cities that are connected together, they form a WAN Internetwork - answer Connection between 2 separate networks Intranet - answer A private network that uses internet technologies but is limited to only users within the private network Extranet - answer A Intranet that is made partially available for entities outside your organization Bus Topology - answer Messages are sent to all devices connected to the bus Ring Topology - answer Messages are sent from device to device in a predetermined order until they reach the destination device

Star Topology - answer Messages are sent directly to (and only to) the destination device Mesh Topology - answer Messages are sent from 1 device to the next around the ring until they reach the destination device What are the 7 layers of the OSI Model - answer Application, Présentation, Session, Transport, Network, Data Link, Physical Application Layer - answer Responsible for integrating network services with the OS Provides an interface between the application running on the system and the rest of the network Uses HTTP, FTP, TFTP, SMTP Presentation Layer - answer Can be referred to as the formatting layer Deals with syntax, encryption, and compression

If you're using HTTP, SSL encrypts the data at the presentation layer Session Layer - answer Responsible for creating sessions between communication devices Each client connection is called a session Session layer uses a Session ID to identify unique sessions Terminates Sessions Transport Layer - answer Responsible for delivering data on a network It receives data from the upper layers. This layer is also responsible for flow control between 2 hosts Uses TCP and UDP Assigns port numbers

Network Layer - answer Responsible for moving data between system throughout the network and is where routing happens. IP Address assignment happens at this layer Uses packets (source and destination IP addresses) Data Link Layer - answer Responsible for interfacing between the physical transmission media. (the physical devices and the network layer) This layer is divided into 2 sub layers: LLC (Logical Link Control): provides the interface between the lower layers and the upper layers MAC (Media Access Control): identifies how devices can access the network medium MAC address is assigned at this layer and uses frames (Source and destination MAC are added)

CRC (Cyclic Redundancy Check): this is also added to the frame at this layer. This helps the receiving device identify errors that may have occurred during transmission. Defines the logical topology of the network. Physical Layer - answer Where we work with physical hardware Works with protocols that identify cables, connectors, and devices we can put on a network Data at this layer is just a series of bits. They become electrical impulses, light pulses, or some kind of radio wave TCP/IP Model - answer Application: Application, Presentation, Session Transport: Transport Internet: Network Network Interface: Data Link

Digital Network Signal - answer Composed of current that have distinct changes A positive volt is considered a '1' A negative volt is considered a '0' Analog Network Signal - answer A continuous electrical current that has no distinct changes, but gradual changes The wave created is adjusting the signals amplitude, or 'strength' overtime Unlike digital signals, it doesn't specifically represent bits Modulation - answer the process of encoding digital signals into an analog signal Demodulation - answer The process of converting analog signals back into digital signals Modem - answer Modulates and demodulates (turns analog signals to digital signals and digital signals to analog signals)

TCP - answer Connection-oriented The computer sending the message does its best to make sure receives the message with no errors. UDP - answer Connectionless Protocol It sends transmissions regardless of whether transmission errors occur Doesn't require destination system to acknowledge delivery Many audio and video streaming services use UDP SMTP - answer SMTP (Simple Mail Transfer Protocol): Used to send mail between email servers. POP3 - answer POP3 (Post Office Protocol v3): downloads emails from the email server and saves them on the client

IMAP - answer IMAP (Internet Message Access Protocol): mail is stored on the email server, and not locally like POP LDAP - answer LDAP (Lightweight Directory Access Protocol): allows users to access directory service information for users on their network such as name, phone number, address etc. SNMP - answer SNMP (Simple Network Management Protocol): let's administrators set up alerts to monitor the state of your network SSL - answer SSL (Secure Sockets Layer): encrypts messages being transmitted on the internet TLS - answer TLS (Transport Layer Security): a step-up from SSL. Ensures that messages being transmitted on the internet are private and tamper proof. Uses DES encryption and uses mutual handshake RJ-11 - answer Has 4 wires/2 pairs Used for phone line RJ-45 - answer Has 8 wires/4 pairs

CAT 3 - answer Supports up to 10 Mbps CAT 5 - answer supports 100/1000 Mbps CAT 5e - answer Supports 100/1000 Mbps w/ EMI protection CAT 6 - answer Supports up to 10 Gbps. Often has a solid plastic core that keeps the twisted pairs separate and prevents cables from being too tightly bent. CAT 6e - answer Supports up to 10 Gbps. Designed to provide better protection against EMI and crosstalk. Also has better performance that CAT 6 especially at 10 Gbps RG-58 - answer uses BMP connector and 10BASE Ethernet RG-59 - answer used for Cable TV primarily, uses F-Type connector RG-6 - answer used primarily for networking, uses F-Type connector, 75 Ohms of resistance (very high)

Define Fiber Optic cabling - answer Immune to EMI and interference. It is used for long-distance and high- bandwidth runs. Uses light pulses instead of electricity to transmit data Single mode Fiber - answer Thin core. Can only transfer data like half-duplex. Multi mode fiber (what is it, and what are the distances for 100 mbps, 1gbps, and 10gbps) - answer Thick core. Can transfer data like full-duplex. (send multiple light pulses at once) Transfer rates: 100 Mbps=2km. 1000Mbps= 1000m. 10 Gbps= 500m ST Connector - answer used with single mode and multimode. Bayonet connector. Push and twist SC Connector - answer used with single mode and multi- mode. Locking-tab connector. Push-in pull-out LC Connector - answer used with single mode and multimode. Plastic connector with locking tab.

MT-RJ connector - answer used with single mode or multimode: uses tabs to make sure that plug is aligned and plugged in properly. Use metal guide pins to ensure correct alignment FC Connector - answer typically used with only single mode: threaded, designed to stay security connected and not pop loose in severe environments Straight-through cable - answer Used to connect unlike devices to each other (router to switch) (PC to switch) T568A Wiring - answer GW, G, OW, B, BW, O, BRW, BR T568B Wiring - answer OW, O, GW, B, BW, G, BRW, BR Demarc - answer The point in the building where the ISP and you meet. Anything outside the demarc is the responsibility of the ISP, anything inside of it is my responsibility MDF - answer Main Distribution Frame (MDF) this is the wiring closet usually closest to the demarc and is usually on the main floor or basement

IDF - answer Intermediate distribution frame (IDF) usually uses vertical cable to connect from MDF. Usually directly above the MDF Demarc Extension - answer If you are on a higher story of a building and don't want other people looking at your data, you can run a cable from the demarc to your floor at the demarc extension then have your MDF by it. Punch Down Block - answer this is used to connect the 25 or 100-pair cable to the IDF. These can then be connected to a patch panel which has RJ-45 ports on one end, and the punch down block on the other end. 66 Block - answer has 25 rows with each row having 4 pins 110 Block - answer is more plastic vs the 66 block which uses metal clips act as metal conductors to connect the wires together

EMI - answer electrical magnetic interference: usually generated by florescent lights or anything that generates electricity like a generator or a high voltage wire. You can use Fiber-optic or STP to help get around this issue. Crosstalk - answer interference that comes from the wires within the cable itself. Alien Crosstalk - answer Happens when 2 separate cables that are near and parallel to each other pick up signal from the other wire. Attenuation - answer the loss of signal strength over distance Impedance Mismatch - answer measure of resistance within the transmission medium and is measured in ohms. The greater the impedance, the more resistance there is Smart Jack - answer A special loopback plug installed at the demarcation point for a WAN service. Allows WAN service provider to remotely run diagnostics, and test for problems. They're able to see if there is any problems with their connection to you through the demarcation.

Define a NIC - answer transmits and receives data over a network What does a Wireless NIC do? - answer converts computer data into radio waves What do Media Converters do? - answer allow you to connect two different types of wires, like UTP to fiber Define a MAC address - answer a 48-bit 12-character number that uniquely identifies a device First 6 characters identify the manufacturer ID, the last 6 characters identify the device's ID What is the Broadcast MAC address? - answer FF-FF-FF- FF-FF-FF RARP - answer RARP (Reverse ARP) is used when a device knows a destination's MAC but not it's IP Hub/repeater - answer Work like a bus topology: relaying data to all devices

Wired physically like a star because all devices connect to it centrally Because hubs don't look at and Bridge - answer A device that connects two (or more) media segments on the same subnet, and it filters traffic between both segments based on the MAC address in the frame. Switch - answer A multiport bridge that performs filtering based on MAC addresses, in addition to providing additional features not found in a bridge When learning MAC addresses for its table, it learns MAC addresses based on the source MAC of the incoming frame When a frame comes in with a destination MAC to an unknown port, the switch sends it to all the ports until one port accepts it WAP - answer Wireless Access Point any message sent to any wireless host connected to the AP can be received by all other wireless hosts

An AP is often configured as a bridge, connecting a wireless segment to a wired segment. Router - answer Makes forwarding decisions based off the IP, not the MAC like a switch would Firewall - answer Determines what network traffic is allowed to enter or leave a network Packet Filtering Firewall - answer make decisions based on the source address and the destination address within each network packet What does a Layer 3 Switch do? - answer similar to a regular switch, but like a router, it makes forwarding decisions based off of the IP of the incoming packet What happens to the MAC and IP when being transferred between routers - answer MAC address changes, destination IP never changes How do routers make forwarding decisions of packets? - answer Routers receive packets, read their headers to find addressing information, and send them on to their correct destination on the network or Internet. To send a

message from one host to another on a different network, the following process is used: The sending host prepares a packet to be sent. It uses its own IP address as the source Network layer address and the IP address of the final receiving device as the destination Network layer address. The sending host creates a frame by adding its own MAC address as the source Physical layer address. For the destination Physical layer address, it uses the MAC address of the default gateway router. The sending host transmits the frame. The next hop router reads the destination MAC address in the frame. Because the frame is addressed to that router, it processes the frame. The router strips off the frame header and examines the packet destination address. It uses the routing table to identify the next hop router in the path. The router repackages the packet into a new frame. It uses its own MAC address as the source Physical layer address and the MAC address of the next hop router as the destination Physical layer address.

The router transmits the frame. The next hop router repeats steps 4 through 7 as necessary, until the frame arrives at the last router in the path. The last router in the path receives the frame and checks the destination IP address contained in the packet. Because the destination device is on a directly connected network, the router creates a frame using its own MAC address as the source Physical layer address, and the MAC address of the destination device as the destination Physical layer address. The router transmits the frame. The destination device receives the frame. Inside the packet it finds that the destination Network layer address match CSMA/CD - answer If there is a transmission currently in progress, the computer wanting to transmit waits a random period of time, then listens again to see if the coast is clear.

If two devices transmit at the same time, a collision occurs. When this happens both devices send out jam signals so that no one else can transmit for a random period of time. This is known as a BACKOFF (Collision Detection) a. Collison - 2 stations are talking at once b. Used with half-duplex What is Full-Duplex? - answer Definition: hosts can transmit and receive at same exact time Provides double the bandwidth as half-duplex Collision detection is turned off. The device can send and receive at the same time. Requires full-duplex capable NICs. Requires switches with dedicated switch ports (a single device per port).

What is Half-Duplex? - answer hosts can only send but not receive at one time or receive and not send at one time. Collision detection is turned on. The device can send or receive in only one direction at a time. Devices connected to a hub must use half-duplex communication. What is inside the frame? (Disregard the packet) - answer The preamble is a set of alternating ones and zeros terminated by two ones (11) that mark it as a frame. The destination address identifies the receiving host's MAC address. The source address identifies the sending host's MAC address. The data is the information that needs to be transmitted from one host to the other.

Optional bits to pad the frame. Ethernet frames are sized between 64 and 1518 bytes. If the frame is smaller than 64 bytes, the sending NIC places "junk" data in the pad to make it the required minimum of 64 bytes. The cyclic redundancy check (CRC) is the result of a mathematical calculation performed on the frame. The CRC helps verify that the frame contents have arrived uncorrupted. SONET - answer A Wide area network technology that uses fiber to multiplex signals across a single wire. Describe the components or Ethernet Specifications of a time that looks like this: 10BaseT or 1000BaseFx - answer i. 10Base__ is 10Mbps, 100Base__ is Fast Ethernet, 1000Base__ is Gigabit, and 10GBase is 10 Gig speeds i. T, FL are used in 10Base (T=CAT 3,4,5; FL=fiber) ii. Tx, Fx, are used in 100Base (Tx=CAT 5 or higher, Fx=fiber) iii. T, Cx (short copper), Sx (short) used in 1000Base. (T=CAT 5e or higher; Cx= special copper of 150ohm or higher; Sx=Fiber) iv. T, SR/SW, LR/LW, ER(extended reach)/EW. Used in 10GBase. (T=Cat 6 or 7; SR/SW=multimode fiber; LR/LW

& ER/EW= Single Mode Fiber) (S=short, L=Long, E=Extended) Ethernet over HDMI - answer Can share data with entertainment devices (Xbox) with a HDMI Ethernet channel (HEC) without requiring additional Ethernet cables. Ethernet over Power Line - answer Allows for network communication over existing AC powerline. This is done by connecting an AC over powerline device into an outlet, then plugging in a network cable (UTP) into the device. Crossover cable - answer connects 2 like devices together (Like a switch to a switch) Uplink port - answer Usually used when connecting a switch to a switch (Daisy chaining) Does not provide standard crossing over function that other ports on a switch do. Rollover Cable - answer (usually has one side RJ-45 and the other side Serial)

Used to connect a workstation to a router or switch directly so the workstation can use terminal for router or switch connectivity What happens if one link in a physical bus topology goes down? - answer if a network cable goes down, the rest of the network after that device go down as well What happens if one link in a physical star topology goes down? - answer If one cable goes down, network still works fine, you just cannot communicate with the device that had its cable go down What happens if one link in a physical ring topology goes down? - answer If a device goes offline, it cannot communicate to the device after it, the device before it can't communicate with it either, other than that, it does not impact the rest of network communications What happens if one link in a physical mesh topology goes down? - answer If one cable goes down, it shouldn't affect network communication almost at all What are the 3 link lights viewable on a switch, router, or hub? - answer Link, Activity, Collision

What does the link light tell me? - answer indicates that there is a physical connection between 2 different devices a. On gigabit NICs, a solid green light indicates full gigabit speeds b. Orange light indicates probable 100 Mbps speeds c. Red light indicates there is probably a physical Layer 1 issue going on On a Activity Light, what does it mean when it is not lit, flashing, or a solid light? - answer a. Not lit: no data being sent to and from the device b. Periodic flashes of light indicate activity and probable valid connections c. Solid light indicates that there is simply a lot of traffic going on. If light is solid, but not being used, this indicates a possible NIC problem On a collision light, what does it mean when it is not lit, flashing, or a solid light? - answer a. If there is no light, that good, that means there are no collisions going on currently b. If the light is on for a little bit, that is normal as collisions happen from time to time c. If the light is steady or flashing frequently, this indicates a mal-functioning network port or that there are too many devices on the network