Download Wired and Wireless Network_L2_Teacher_Powerpoint

1.4 WIRED AND WIRELESS
NETWORKS LESSON 2
© OCR 2016
The Big Picture:
Wired and wireless networks
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•
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Types of networks:
 LAN (local area network) & WAN (wide area network)
 The different roles of computers in a client-server and a peer-to-peer network
• Factors that affect the performance of networks
• Network topologies
The hardware needed to connect stand-alone computers into a local area network:
• Wireless access points
• Routers/switches
• NIC (network interface controller/card)
• Transmission media
The internet as a worldwide collection of computer networks:
• DNS (domain name server)
• Hosting
• The cloud
• The concept of virtual networks
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Thought for the day - Networks
At peak capacity,
Netflix uses 1/3 of all
Internet traffic in
North America!
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Starter: Recap P2P and C-S
Peer to Peer?
1 -Each computer acts as a 'host'.
Users can access files and
peripherals directly from all the
other nodes on the network.
2 -The files are stored on the hard disks of
individual network machines.
3 -Workstations cannot normally 'see' or share
data with each other directly over the
network.
4 - Users will have their own private area on
the network where they can save their files
and documents. No one else can access this
area (except the network manager/staff).
Client – Server?
5 - Each computer on the
network has equal importance
and no more privileges than any
other.
6 - All computers on the network
connect through a central hub or
switch.
7 - Very common in small offices
or at home where there are only
a few computers connected
together.
8 - There may be multiple shared folders
on a server with different access rights.
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Starter: Recap - Network Types
Network
Meaning
Example
LAN
WAN
PAN
VPN
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Starter: Recap - Network Types
Network
LAN
WAN
PAN
VPN
Meaning
Local Area Network
Wide Area Network
Personal Area Network
Virtual Private Network
Example
School
Cash Dispensers
Laptop
Mobile
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Learning Objectives
By the end of today’s lesson, you will:
• Identify the components required to create a LAN
• Describe the role of each component in a LAN
• Understand what is meant by the performance of a
network and why this is important
• Explain the factors that can affect the performance
of a network
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Transfer of data over a network:
Packets
• Data transmitted over a network is broken down into
packets.
• Each packet contains the address of the sender and
the address of the receiver (IP addresses)
• Packets will also contain a sequence number so
they can be re-packaged at the receiving end
• Packets will have a time to live (how many hops
around the network they can take before they
disappear
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Network Performance
Latency
• Network latency is how much
• Describes how much data
time it takes for a packet of
can be transferred over a
data to get from one
connection in a given time.
designated point to another.
• The speed of a network is
• Latency is measured by
measured in bits per
sending a packet that is
second.
returned to the sender; the
• Ideally you would want as
round-trip time is considered
much bandwidth as possible
the latency.
to enable as much data as
• Ideally, latency is as close to
possible to be transferred
zero as possible.
within that second
Bandwidth
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Latency
•
Network latency is any kind of delay that happens in data communication over a
network.
• So you want a network with low latency as this will mean there is less of a delay in
data communication between devices.
• Latency prevents the data from taking full advantage of the available bandwidth.
The problem could be temporary or ongoing depending on the issue.
Possible contributors to network latency include:
• Problems with the transmission medium itself.
• Errors with the router or switches as each gateway takes time to examine and
change the packet header for the next part of the packets journey.
• Anti-virus and similar security processes
• The time it takes for a packet to physically travel from its source to a destination.
• Storage delays when packets are subject to storage or disk access delays at
devices like switches and bridges.
• Software malfunctions at the user level can cause some delays from a user
perspective.
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Brainstorm
• What hardware do we need to create a LAN?
• How will the computers be connected together and
what might be required to do this?
• What do we mean by the performance of a network
and why this might be important?
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Hardware components
What is the role of the following hardware components
in a network?
• Wireless access point (WAP)
• Router
• Switch
• Network interface card (NIC)
• Transmission media
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Bandwidth
• Bandwidth is also defined as the amount of data that
can be transmitted in a fixed amount of time.
• A LAN has bandwidth in the same way as a WAN
such as the Internet has.
• Your broadband provider will give you an idea of
what your bandwidth is, often quoting the maximum
available.
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Network Hardware
• https://youtu.be/PPr9Oa_jj1Q?list=PLCiOXwirraUAv
kTPDWeeSqAKty3LAG37-
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Wireless Access Point (WAP)
• Allows for wireless devices to connect to a network
(either LAN or WAN)
• Includes connections through Wifi and Bluetooth
• WAPs provide Internet access in public places
(often known as Wi-Fi hotspots)
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Router
• An interconnection device used on networks to connect
two or more devices.
• Routers contain a routing table which has a list of IP
addresses and common routes for packets to take
• Routers examine packets IP addresses
• The router will apply a subnet mask to identify a network
and determine which network the packet should be
forwarded to
• If the packet is for this network – the router determines
which host to send the packet to
• Routers allow packets from different network types to be
exchanged
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Switch
• If two or more computers place a packet onto a
network at the same time – a data collision occurs
• A switch is an interconnection device that connects
two or more devices together and helps in solving
the issue of data collisions
• As a data packet arrives at the switch – its
destination address is examined and the switch
creates a direct connection to that device
• As far as the two devices are concerned there are
no other computers on the network (see example)
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NIC Network Interface Card
• A network interface card allows a computer to
connect to a wired network
• A NIC allows data packets to travel to and from a
computer
• A NIC contains a MAC address which is a physical
hardware address
• A NIC allows an Ethernet cable to be plugged into
this
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Transmission Media
• Ethernet (Cat 5e / Cat6)
• Known as twisted pair
• A networking standard
• Fibre optic
• Very fast cable but also more expensive (often used
with WAN or larger LANs)
• Coaxial Cable
• An older networking standard
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Show your understanding
1. Match up the hardware term and its definition on
the worksheet.
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Network performance
Measures of computer network performance are commonly stated in units of bits per
second (bps). This quantity can represent either an actual data rate or a limit to
available network bandwidth.
Modern networks support very large numbers of bits per second. Instead of quoting
10,000 or 100,000 bps, networks normally express these quantities in terms
of kilobits, megabits, and gigabits.
•1 Kbps = 1 kbps = 1 kilobit per second = 1,000 bits per second
•1 Mbps = 1,000 Kbps
•1 Gbps = 1,000 Mbps
In networking, both "kbps" with a lowercase "k" and “
Kbps" with an uppercase "K" can be used interchangeably.
https://www.youtube.com/watch?v=vTP6mdC
w1uE&list=PLCiOXwirraUAvkTPDWeeSqAKty
3LAG37-&index=12
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Show your understanding
1. Match up the hardware term and its definition on
the worksheet.
2. Create a leaflet for a networking novice to explain:
• The hardware components and their functions
• How they can get the best out of their network explain the factors that can affect the performance of
a network and how these can possibly be overcome.
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Plenary: Define Key Words
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LAN
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Packet
Wireless access point (WAP) •
Router
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Switch
Ethernet cable
Network interface card
(NIC)
Transmission media
Network performance
© OCR 2016