3213 Quiz 1 Flashcards

1
Q

What is ARPANET
-Type of connection, and name?

A

Computer to computer network
Wide area network

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2
Q

How does ARPANET work

A

Switched network infrastructure
Packets of fixed size

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3
Q

What is circuit switching? (Wired telephone network)
Pros/Cons?

A

Dedicated path between 1 or more links
Pros: Guaranteed QoS, fixed transmission rate, no data loss
Cons: Inefficient, and complex. One connection suffocates link vs packet switching

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4
Q

What is Packet switching (ARPANET, Internet, 3G+)
Pros/Cons?

A

No dedicated path, packets transmitted independently.
Pros: links shared by many packets, packets accepted even under heavy traffic.
Cons: No QoS guarantee, packet delay/loss during traffic, overhead encapsulation traffic.

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5
Q

LAN network topologies

A

Bus Topology
- Simple/inexpensive
- Single point of failure, collision = diminishing capacity
Ring Topology
- small frame (token) circulates dictating who can transmit data
- Fair access
- Breaks if any link fails
Star topology
- Each station connected directly to central node
- Central node broadcast and/or switch

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6
Q

Hub vs Switch?

A

Only one station can transmit otherwise collision occurs, and broadcast data to all connected computers
Switch: Sends data only to specified computers.

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7
Q

IP Addressing (Address format + Routing)

A

IP Address = Net ID + Host ID
IP Packets are routed only based on Net ID in destination IP Address
- Only has to know major networks/ smaller routing table -> Faster routing

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8
Q

What is a protocol and its data unit type?

A

Set of rules that govern how two or more entities in a layer are interacting
ex: HTTP, TCP, IP
Communicate by exchanging Protocol Data units (PDU’s)

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9
Q

What are services

A

Services wrapped in PDU’s, available at Serice Access Points (SAP)
layer n+1 transfers info by invoking services by layer n

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10
Q

What is a Data link layer?
4 Main actions

A

Attempts to provide reliable communication over physical layer(same network)
Divides stream of bits into frames
adds header to specify address of receiver (MAC)
Adds trailer to header to detect/recover lost frames
Flow control

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11
Q

What is a Network Layer
- Addressing, Routing, frag

A

Oversees delivery of packets between devices across multiple networks/links
- Logical addressing / scale to large networks
- provides routing for optimal path across large internetwork
- Fragmentation and reassembly of packets to accommodate different media.

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12
Q

What is a transport layer?
Purpose

A

Network layer gets packet to receiver, transport gets entire message to correct process on receiver.
- Reliable mechanism for process to process
- Ensures data units are delivered error free, in sequence, with no loss/dup

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13
Q

Transport Layer supporting purpose
- Addressing, segment, flow

A

Port addressing: Specifies port address to send to receiver
Segmentation and reassembly: Divide into segments containing sequence number, to reassemble message correctly, and identify/replace missing packets.
Flow and error control: Performed end to end

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13
Q

The application layer does what?

A

Provides actual service/ interface to the user

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14
Q

OSI Downfall reason?

A

TCP/IP Launched same time with 5 layer, less complex, more efficient

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15
Q

TCP/IP Address model

A

Port address: Locally unique to differentiate different applications using same IP Address

IP Address: Globally unique, corresponding node in entire internet.

Physical Address: Globally Unique, or MAC Address, used to locate on LAN

16
Q

TCP/IP Encapsulation Model

A

TCP Header contains source and destination port numbers
IP Header contains source and destination IP addresses (Transport and protocol type)
D.L Header contains source and dest. MAC addresses (network protocol type)

17
Q

Analog Data

A

Refers to info that is continuous, continuous values in some interval

18
Q

Digital Data

A

Refers to discrete states, finite/countable number of values in range

19
Q

How many links for Mesh, ring, bus, and star topology

A

Mesh = n(n-1)/2
Ring = n links
Bus = n+1 (backbone link required)
Star = n + 1 (backbone link required)

20
Q

Sine wave components

A

Simple - cannot be decomposed further
Peak amplitude
Frequency
Phase

21
Q

Phase and deg/rad conversion

A

%offset respect to time = 0
360 = 2 pi rad

radians = degrees * pi / 180

22
Q

Freq/period relation

A

Frequency = completed cycles per second
Freq = 1/T
Period = Time to complete 1 cycle
Period = 1/f
Inversely proportional

23
Q

If composite signal is periodic, decomp of signals give signals with?

A

discrete freq

24
Q

If composite signal is non-periodic, decomp of signals give signals with?

A

continuous freq

25
Q

f is referred to as? (ex: freq = 3f)
int multiples of f are referred to as?

A

fundamental frequency
harmonics

26
Q

bit interval?
bit rate?

A

time required to send single bit
number of bit intervals per second

27
Q

A digital signal has 8 levels. How many bits can be represented per level?

A

log base 2 (8) = 3
3 bits represented per level

28
Q

digital signal, with all its
sudden changes mean what?

A

composite signal with infinite # of frequencies
Note: To create a perfect square wave of a composite signal, we must add all harmonic frequencies up to infinity to flush out the square shape.
Thus infinite # of frequencies.

29
Q

Bandwidth of a composite periodic analog signal is found how?
Why not digital?

A

Difference between highest and lowest frequencies in that signal
(B = f high - f low)
Digital has infinite frequency

30
Q

A nonperiodic composite analog signal has a bandwidth of 200 kHz,
with a middle frequency of 140 kHz and peak amplitude of 20 V.
The two extreme frequencies have an amplitude of 0. What is the lowest freq, and highest?

A

low=40, high = 240

31
Q
A