T3 - LANs and WANs: Flashcards

1
Q

Internet

A
  • is a collection of inter-connected networks
    Largest WAN
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2
Q

WAN

A
  • Any network in which the computers communicate using resources supplied by a ‘third party carrier’ such as BT
    -Covers a large geographical area
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3
Q

wans use

A

uses cables, telephone lines, satellites or radio waves to connect two or more remote locations

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4
Q

IPv4 addresses are

A

four 8-bit numbers (0-255) separated by dots

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5
Q

Newer IPv6 addresses are

A

128-bit numbers represented in hex

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6
Q

WAN stands for

A

– Wide Area Network (large geographical area)

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7
Q

Packet –

A

one unit of data sent through an IP network

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8
Q

Routing –

A

directing IP packets to their destinations

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9
Q

DNS stands for

A

– Domain Name System

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10
Q

IP address –

A

Internet Protocol address. Where packets of data are sent to or received from

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11
Q

MAC address

A

– Media Access Control address. The unique identifier of each device (or network interface card)

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12
Q

Packet switching:

A

file is broken up into data ‘packets’

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13
Q

packets contain info on

A

The IP address it is going to
The IP address it has come from
The sequence number of the packet
The number of packets in the
whole communication
Error checking data

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14
Q

Data Packets:

A

contain the same number of bytes
packets may flow through the Internet via different routes
marked with the packet number = can be reordered and checked for errors

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15
Q

Routers

A
  • any node that can route packets from one place to another
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16
Q

IP address: dynamic IP address

A
  • IP addresses will change when the router reconnects to the Internet.
    actual geographical location of a networked device can be determined by this
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17
Q

Network interface card

A
  • built into every networked device
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18
Q

Domain Name System (DNS) description

A

made up of domain names
Refers to IP address

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19
Q

A DNS server translates

A

a web address into an IP address

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20
Q

13 DNS root servers worldwide which

A

keep a complete database of all domain names and IP addresses

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21
Q

how many DNS root servers

A

13

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22
Q

When a DNS server receives a request not in its database,

A

it will pass the request on to another server until it reaches one with the matching name and IP address

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23
Q

MAC addressing -

A

assigned to each Network Interface Card (NIC) by the manufacturer = unique, never changes

24
Q

MAC addressing: When you request a web page,

A

each router along the way uses the MAC address of the next router to send the data packet on the next leg of its journey

25
Q

LAN

A
  • operates on a single site such as a school, hotel or business using their own cabling systems
26
Q

Topology

A
  • the way in which
    parts of a system are connected
27
Q

eg of topology

A

Eg Star and Mesh

28
Q

pros of networks

A

Computers can share resources such as printers
Files can be accessed through any computer in the network
Data is easy to back up as it is stored centrally on the server

29
Q

cons of networks

A

Purchasing the network hardware is expensive
Managing a large network is complicated
Viruses may be able to infiltrate the network and infect every computer

30
Q

Star Network:

A

computers and other devices (known as nodes) are all connected to a central switch

31
Q

Star Network: pros

A

Fast data transfer to the hub as each wire isn’t shared with other computers
If one cable fails the other computers are not affected

32
Q

Star Network: cons

A

Requires additional hardware such as the central switch and network cables
If the central switch fails the whole network goes down

33
Q

Full Mesh network:

A

Nodes act as routers for data in order to relay and propagate data in the network

34
Q

A partial mesh network

A

is usually used, often in conjunction with star topologies to create larger networks

35
Q

Internet -

A

combines many networks together, but many parts operate as a partial mesh

36
Q

Many LANs that connect to the Internet use a

A

star topology,

37
Q

Wireless mesh networks:

A

Only one node needs a wired Internet connection – no other cabling or infrastructure is required

38
Q

The more nodes that use the network,

A

the more routes there are for data to travel through

39
Q

A node within broadcast distance of three other nodes,

A

will have triple the standard bandwidth

40
Q

As the distance between one node and another is halved,

A

signal strength becomes four times stronger

41
Q

Mesh networks: pros

A

No single point of failure – it is resilient
Expansion and modification can be done without disrupting the network
Data can be transmitted from different devices simultaneously

42
Q

Mesh networks: cons

A
  • Can involve redundant connections
  • Expensive to install cabling if using wired connections
  • Network maintenance and administration is difficult
43
Q

Network Hardware:

A
  • NIC
    -router
    -switch
  • modem
  • WAP
    -Hub
44
Q

A Network Interface Card/Controller (NIC)

A

in your computer or device

45
Q

A router or switch,

A

which provides access to a local area network

46
Q

A modem

A

is required to connect to the Internet – this is usually combined with the router inside a single device

47
Q

A Wireless Access Point

A

connects wireless devices to a network. Many home wireless access points are part of a router

48
Q

Router:

A

Looks at the destination of packets of data and sends them to the network that is closer towards
their destination

49
Q

A home router will route packets between

A

the home LAN and the Internet

50
Q

Switch:

A

Switches connect each node (computer) in a network
They know the MAC address of all connected computers and devices
When a packet of data arrives, they can send it to the correct computer

51
Q

Hubs,

A

by comparison will send the data to all connected computers

52
Q

Ethernet: refers to

A

refers to a family of standard local networking ‘protocols’ or rules

53
Q

Ethernet describes

A

describes how devices should format data ready for transmission between computers on the same network

54
Q

Ethernet works by

A

nodes will wait until the connection is quiet before attempting to ‘speak’ or transmit
Two nodes attempting to transmit simultaneously will stop and each wait a random period before reattempting

55
Q

Transmission media:

A

way that communication is sent through the network

56
Q

Ethernet is sent through

A

twisted copper cables or fibre optic cables