Test2Review

Question 1

What are the 2 types of network media transmission & examples of each?

Answer 1

Guided - copper, fiber optics.

Unguided - radio waves, wireless

Question 2

Frequency (with waves) definition, an measurement unit

Answer 2

Frequency = number of oscillations/second. Unit = Hertz.

Question 3

Coaxial cable composition.

Answer 3

Composed of 2 conductors - inner (insulated) one for data transmission, and outer braided metal shield to protect the data.

Question 4

2 types of coax cable connectors.

Answer 4

BNC & F-connector.

Question 5

2 types of twisted-pair cabling.

Answer 5

Unshielded Twisted Pair (UTP) & Shielded Twisted Pair (STP). UTP has 4 pairs of insulated copper wires and has some resistance to EMI. STP also has 4 pairs of insulated copper wires and each pair is wrapped in foil, and all 4 pairs are wrapped in wire mesh. STP is very resistant to EMI.

Question 6

Category of UTP & STP.

Answer 6

UTP = cat 6. STP = cat 7.

Question 7

What is RJ-45?

Answer 7

Used with ethernet. 8-pin connector.

Question 8

What is RJ-11?

Answer 8

Used on most home telephone networks. 4-pin connector.

Question 9

What is DB-9, and is it sync or async?

Answer 9

9-pin connector. Used to connect the serial port on a computer to a networking device. Asynchronous serial communication.

Question 10

What is USB & (sync/async)?

Answer 10

Universal serial bus. Synchronous communication.

Question 11

USB 2.0 & 3.0 data rate.

Answer 11

USB 2.0 is up to 480 mbps. USB 3.0 up to 5 gbps.

Question 12

What is fiber optic cabling?

Answer 12

Uses light from an LED or laser to transmit info through a glass fiber.

Question 13

2 categories of fiber optic cable.

Answer 13

Multimode fiber (MMF) & Single-mode fiber (SMF).

Question 14

MMF core size & usage.

Answer 14

Core size = 62.5 microns. Usage = router -> switch, switch -> switch, server -> switch

Question 15

SMF core size & usage.

Answer 15

Core size = 10 microns. Usage = routers -> switches, switches -> switches.

Question 16

Fiber optic vs copper (benefits of both)

Answer 16

Copper: cheaper, easy to install, inexpensive tools.

Fiber optic: higher bandwidth, longer distances, immune to EMI, better security, does not corrode.

Question 17

What is the ethernet standard? (IEEE….)

Answer 17

IEEE 802.3

Question 18

CSMA/CD definition.

Answer 18

Carrier Sense Multiple Access/Collision Detection

Question 19

What is carrier sense?

Answer 19

Listen to the wire and verify that it is not busy. If it is busy, keep listening until it’s free.

Question 20

What is multiple access?

Answer 20

All devices have access to the wire at the same time.

Question 21

What is collision detection?

Answer 21

If 2 devices transmit at the same time, a collision occurs. Back off & wait a random time, then try again.

Question 22

What is needed in ethernet frame for ARP & DHCP?

Answer 22

MAC address.

Question 23

How many bits in MAC address?

Answer 23

48

Question 24

What is MAC broadcast address?

Answer 24

All 48 bits are 1’s. FF:FF:FF:FF:FF:FF

Question 25

What is a HUB?

Answer 25

Takes every incoming bit on a port & repeats it on every other port.

Question 26

HUB OSI layer & topology.

Answer 26

Layer 1. Physically a star topology but logically a bus.

Question 27

What is a bridge?

Answer 27

Joins 2 or more LAN segments. Analyze source MAC addresses in frames entering the bridge & populate and internal MAC address table based on those addresses. Make intelligent forwarding decisions based on the destination MAC address in the frame.

Question 28

Why switch replace bridge?

Answer 28

Bridge makes forwarding decisions in software. Switch makes forwarding decisions in hardware using application-specific integrated circuits (ASIC). This reduces cost, has more features, and better performance.

Question 29

OSI layer of switches.

Answer 29

Layer 2.

Question 30

What are collision & broadcast domains?

Answer 30

Collision - set of all devices whose transmissions can cause collision of frames. Broadcast - set of all devices that receive a frame if one of them indicates a broadcast address in its transmitted frame.

Question 31

of collision & broadcast domains in HUB.

Answer 31

1 collision, 1 broadcast

Question 32

of collision & broadcast domains in bridge.

Answer 32

2 collision, 1 broadcast

Question 33

of collision & broadcast domains in switches

Answer 33

4 collision, 1 broadcast

Question 34

of collision & broadcast domains in routers

Answer 34

8 collision, 2 broadcast.

Question 35

What is a multilayer switch?

Answer 35

Combine features of layer 2 switches & layer 3 routers. Can make decisions based on both MAC & IP addresses.

Question 36

of collision & broadcast domains in multilayer switch?

Answer 36

4 collision, 4 broadcast.

Question 37

VPN definition.

Answer 37

VPN = virtual private network. Allows secure communication via a tunnel network over an untrusted network.

Question 38

What is a Firewall?

Answer 38

Network security appliance. Guards entrance to your network. Protects from malicious internet traffic. Can be software or hardware.

Question 39

What is DNS?

Answer 39

Domain Name System. Takes a domain name like google.com and resolves it to an IP address.

Question 40

How DNS service is established.

Answer 40

PC requests the IP address for a website. DNS server responds with the IP address. Packet is sent to the desired web server.