Network Topology Flashcards

1
Q

What are the 2 types of communication technologies?

A

Point-to-point, multi-access

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2
Q

What is point-to-point?

A

connect precisely two computers

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3
Q

What is Multi-Access?

A

connect multiple computers over shared medium

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4
Q

What is the star network?

A

all computers connected to a central point (hub)

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5
Q

What is a ring network?

A

forms a closed loop with each computer connected to the next 1

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6
Q

how is data transmitted in ring network?

A

packets are passed around the ring until they reach the destination

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7
Q

what is a drawback of ring network?

A

if any cable is cut the network is broken

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8
Q

what happens when the data is transmitted in ring network?

A

it returns back to sender who can check for any errors
recipient makes a copy as it goes past

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9
Q

what are mechanisms to co-ordinate access?

A

full/empty slots
token passing

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10
Q

How does token work in ring network?

A

its passed around the ring from network to network basically telling it that it can send data

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11
Q

what does a computer do when it receives token?

A

waits for token to arrive
if packet is available to send then send it
pass token to next station

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12
Q

What is the bus network?

A

all computers connected to a single long wire

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13
Q

what happens if a computer sends something on bus network?

A

signal is sent to every other computer and the intended recipient can receive it

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14
Q

what needs to be ensured on bus network?

A

transmits one at a time to avoid collisions

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15
Q

What is a collision?

A

2 computers transmit at same time so packets collide and can become corrupted

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16
Q

How do we avoid collission on bus networks?

A

use access control so only 1 computer transmits at a time

17
Q

What one approach from access control?

A

time division multiplexing?

18
Q

What is TDM?

A
  • Controller synchronises machines to communicate in fixed time-slots
  • Each machine gets a fixed amount of bandwidth from the whole medium
19
Q

Advantages of TDM?

A

great for multi tenancy (everyone gets what they pay for)
bandwith shared equally

20
Q

Disadvantage of TDM?

A

doesnt use bandwith effectively

21
Q

What is DOCSIS used for?

A

for cable modem

22
Q

What is PON?

A

Passive optical network
provides connectivity over a passively split fibre network

23
Q

what do both DOCSIS and PON assume?

A

asymmetric traffic

24
Q

what is asymmetric traffic?

A

user downloads more than they send

25
Q

Whats another approach besides TDM?

A

Eventual packet delivery

26
Q

What is eventual packet delivery?

A

which basically accepts collissions will take place but can recover and eventually it will arrive