1 - Basic Networking

Question 1

What IEEE standard number covers all Ethernet standards?

Answer 1

802.3

Question 2

What suffixes are used for UTP cabling and Fiber cabling in informal IEEE Ethernet standard names?

Answer 2

T for UTP

X for Fiber

Question 3

What are the IEEE standard and names for Ethernet and Fast Ethernet?

Answer 3

10BASE-T (802.3)

100BASE-T (802.3u)

Question 4

What are the IEEE standard and names for both UTP and Fiber Gigabit Ethernet?

Answer 4

1000BASE-LX (802.3z) Fiber

1000BASE-T (802.3ab) UTP

Question 5

What is the IEEE standard and name for 10 Gig Ethernet?

Answer 5

10GBASE-T (802.3an)

Question 6

How many twisted pairs does 10BASE-T and 100BASE-T require?

Answer 6

2

Question 7

How many twisted pairs does 1000BASE-T require?

Answer 7

4

Question 8

Which twisted pair wire / pin numbers do Ethernet NICs and Routers use to transmit and receive on respectively?

Answer 8

Transmission on pins 1 and 2

Receive on pins 3 and 6

Question 9

Which twisted pair wire / pin numbers do Switches use to transmit and receive on respectively?

Answer 9

Transmission on pairs 3 and 6

Receive on pins 1 and 2

Question 10

What type of cable must be used to connect a PC NIC to a switch?

Answer 10

Straight through cable. (1-1, 2-2, 3-3, 6-6, etc)

Question 11

What type of cable is used for connecting nodes that use opposite pairs for transmitting? e.g. PC NIC / Router to Switch?

Answer 11

Straight through cable

Question 12

What type of cable must you use for connecting like devices that transmit on the same pins? e.g Hub, Switch to Switch (10 and 100 Mbps Ethernet)

Answer 12

Crossover cable

Question 13

In 10BASE-T and 100BASE-T which types of devices transmit on Pins 1 and 2?

Answer 13

Routers, PC NICs and Wireless access points (Ethernet interface)

Question 14

In 10BASE-T and 100BASE-T which two types of devices transmit on Pins 3 and 6?

Answer 14

Switches and Hubs

Question 15

What is auto-mdix?

Answer 15

A feature on Switches that detects when the wrong cable is used and automatically changes the logic to make the link work

Question 16

What are the layers of a Fiber Optic Cable?

Answer 16

Core, Cladding, Buffer, Strengthener, Outer jacket

Question 17

What mode of Fiber allows for multiple angles (modes) of light entering the core? What type of transmitter is used?

Answer 17

Multimode. LED

Question 18

Which mode of fiber uses a smaller core with a transmitter sending light at one angle? What type of transmitter is used?

Answer 18

Single mode. Laser

Question 19

What is SFP/SFP+?

Answer 19

Small Form Pluggable, allow customer to change transceiver as module in Switches. E.g. switch to optical fiber ethernet

Question 20

What mode of Fiber is useful for very long distances?

Answer 20

Single mode

Question 21

List the following cable modes in order of least expensive to most expensive: Multi-mode fiber, UTP, Single-mode fiber?

Answer 21

UTP, Multi-mode, Single-mode

Question 22

What does Half Duplex mean for a device?

Answer 22

The device can only send when it is not receiving a frame i.e. it cannot send and receive a frame at the same time

Question 23

What does Full Duplex mean for a device?

Answer 23

A device can send and receive at the same time

Question 24

What layer of standards does a Hub use to forward data, and how does it do this?

Answer 24

Physical layer standards. A hub repeats electronic signals out all ports (except incoming)

Question 25

What is a big downside of LAN hubs?

Answer 25

If more than one device transmits at the same time, the signals collide and become messed up

Question 26

How does CSMA/CD work?

Answer 26

Sending device listens to link until its free. Sends a frame. If device detects a collision, all devices send a jamming signal, wait a random amount of time, then try again

Question 27

How many bytes are in an Ethernet FCS? Where is it located?

Answer 27

4 bytes. In the Ethernet Trailer

Question 28

How many bytes is the Ether Type field?

Answer 28

2 bytes

Question 29

What are the two most popular Data link layer protocols for leased lines between two routers?

Answer 29

HDLC (High level data link control) and PPP

Question 30

What is the Flag field in HDLC used for and whats its Ethernet equivalent?

Answer 30

Recognizable bit pattern so receivers know a new frame is arriving. Equivalent to Preamble, SFD

Question 31

What field is proprietary to each vendor in HDLC?

Answer 31

Type field

Question 32

What function does HDLC provide?

Answer 32

HDLC frames provide a way to encapsulate network layer packet correctly so it crosses the link between routers.

Question 33

What protocol is broadcast, multi access?

Answer 33

Ethernet

Question 34

What protocol is non broadcast, point to point?

Answer 34

HDLC

Question 35

Do Serial interfaces have MAC addresses? Why?

Answer 35

No. They do not need them. Serial interfaces are only used for Point to Point links

Question 36

What is an Ethernet Line Service (E-Line)?

Answer 36

Term for the point to point Ethernet WAN service

Question 37

What is Ethernet emulation?

Answer 37

A term highlighting a link is not a literal Ethernet link from end to end

Question 38

What is EoMPLS?

Answer 38

Ethernet over Multi Protocol Label Switching. Used to create Ethernet service. Acts as if it were a simple Ethernet link between two routers

Question 39

What port does DNS use?

Answer 39

53

Question 40

What port does TCP use?

Answer 40

57

Question 41

Do Optical cables suffer from EMI?

Answer 41

No

Question 42

What is macro-bending?

Answer 42

If a fiber-optic cable is bent too much, and it prevents the cable transmitting bits