Transcript Networks Continued - Fox Valley Technical College

Networks Continued
What does MAN stand for?
Metropolitan Area Network
What does NAN stand for?
Neighborhood Area Network
What does LAN stand for?
Local Area Network
What does WAN stand for?
Wide Area Network
What does PAN stand for?
Personal Area Network
Name that topology!
Tree
Topologies, such as the Ring Topology, can have
redundancy built in so that if one node fails data can
travel an alternate route to the destination
5 Network Links
 A communications channel, or link, is a physical path or
frequency for signal transmissions
 Bandwidth is the transmission capacity of a communications
channel
– Broadband
– Narrowband
Chapter 5: LANs and WLANs
9
5 Communications Protocols
 A packet is a “parcel” of
data that is sent across a
computer network
– Circuit-switching
technology vs. packet
switching technology
Chapter 5: LANs and WLANs
10
Circuit Switching
• Dedicated communication path between two nodes
• Inefficient
• Path capacity dedicated for duration of connection
• example: telephone system
Packet Switching
• efficient
• Single node to node link can be shared by many
packets over time
• example: internet
5 Communications Protocols
 Rules for efficiently transmitting data from one network node
to another
– Divide messages into packets
– Affix addresses to packets
– Initiate transmission
– Regulate flow of data
– Check for transmission errors
– Acknowledge receipt of transmitted data
Chapter 5: LANs and WLANs
13
5 Communications Protocols
 Every packet that travels over a network includes the
address of its destination device
 A MAC address is a unique number assigned to a network
interface card when it is manufactured
 An IP address is a series of numbers used to identify a
network device
 IP addresses can also be obtained through DHCP
Chapter 5: LANs and WLANs
14
DHCP
Stands for Dynamic Host Configuration Protocol
It is an auto-configuration protocol used on IP networks.
Computers that are connected to IP networks must be
configured before they can communicate with other computers
on the network. DHCP allows a computer to be configured
automatically, eliminating the need for intervention by a network
administrator. It also provides a central database for keeping
track of computers that have been connected to the network.
This prevents two computers from accidentally being configured
with the same IP address
Name that topology!
Bus
5 Wired Network Basics
 A wired network uses cables to connect network devices
 Wired networks are fast, secure, and simple to configure
 Devices tethered to cables
have limited mobility
Chapter 5: LANs and WLANs
17
5 Ethernet
 Simultaneously broadcasts data packets to all network
devices
– IEEE 802.3
– CSMA/CD protocol
 Vary in speed from 10Mbps to 100Gbps
Chapter 5: LANs and WLANs
18
Ethernet
• is the most widespread wired LAN technology
5 Ethernet
On an Ethernet, data
travels on a first-come,
first-served basis. If two
workstations attempt to
send data at the same
time, a collision occurs.
That data must be
resent.
Chapter 5: LANs and WLANs
20
5 Ethernet Equipment
Chapter 5: LANs and WLANs
21
5 Ethernet Equipment
 Ethernet adapter (designed to support the Ethernet
protocols)
 Network hub
 Network switch
 Network router
 RJ45 connector
Chapter 5: LANs and WLANs
22
Hubs, Switches, & Routers
• Hub: basic networking component used to
connect computers to form a LAN
– a data packet coming from one port is sent to all
other ports
– basically organizes your cables and relays data
signals to all computers on the LAN
Hubs, Switches, & Routers
• Switch: networking device that controls the
flow of data by using the MAC address that is
placed on each data packet
– Switches divide networks into Virtual LANS (VLAN)
– becoming very popular on both small and large
networks
Hubs, Switches, & Routers
• Router: utilize a combination of
hardware/software to actually route data from
source to destination
– utilizes IP addresses
– divides large networks into logical segments
called subnets
5 Ethernet Setup
Chapter 5: LANs and WLANs
26
5 Ethernet Setup
Most routers are
configured using a
browser. You should
change the network
administrator password,
then verify that DHCP is
enabled
Chapter 5: LANs and WLANs
27
Name that topology!
Star
5 Wireless Basics
 A wireless network transports data from one device to
another without cables or wires
– RF signals
• Transceiver
– Microwaves
– Infrared light
 Slower than wired networks
 Security concerns
Chapter 5: LANs and WLANs
29
5 Bluetooth
 Bluetooth is a short-range, wireless network technology
designed to make its own connections between electronic
devices, without wires, cables, or any direct action from a
user
Chapter 5: LANs and WLANs
30
5 Wi-Fi Equipment
 If your computer is not pre-equipped with wireless circuitry,
you can purchase and install a Wi-Fi card
Chapter 5: LANs and WLANs
31
5 Sharing Files
 If you use Windows, it
automatically detects
available LANs any time
you turn on a workstation
 To connect to a shared
resource, you might be
asked for a user ID and
password
Chapter 5: LANs and WLANs
32
5 Troubleshooting
 Network problems can stem from a variety of sources
– Cables
– Signal strength
– Security
– Interference
– Network devices
– Settings
Chapter 5: LANs and WLANs
33
Name that topology!
Mesh
Security
5 Wi-Fi Security
 Wireless networks are much more susceptible to
unauthorized access and use than wired networks
 LAN jacking, or war driving, is the practice of intercepting
wireless signals by cruising through an area
Chapter 5: LANs and WLANs
36
5 Wi-Fi Security
 Wireless encryption scrambles data transmitted between
wireless devices and then unscrambles the data only on
devices that have a valid encryption key
– WEP (Wired Equivalent Privacy)
– WPA (Wi-Fi Protected Access)
– WPA2
– PSK
 Activate encryption by using a wireless network key
Chapter 5: LANs and WLANs
37
5 Encryption
 Encryption transforms a message so that its contents are
hidden from unauthorized readers
– Plaintext has not yet been encrypted
 Decryption is the opposite of encryption
– Cryptographic algorithm
– Cryptographic key
Chapter 5: LANs and WLANs
38
5 Encryption
 Weak vs. strong encryption
 AES (Advanced Encryption Standard)
– standard adopted by the U.S. government
 Encryption methods can be broken by the use of expensive,
specialized, code-breaking computers
– Brute-force method
Chapter 5: LANs and WLANs
39
5 Encryption
 Public key encryption (PKE) eliminates key-distribution
problem, by using one key to encrypt a message and
another key to decrypt the message
Chapter 5: LANs and WLANs
40
PKE (Public Key Encryption)
• You can think of it as a locked front door to a
building, and the door has a mail slot
– Mail slot is exposed and accessible to the public;
its location (street address) is like the public key
– Anyone knowing the address can go to the door
and drop a message through the slot
– Only the person possessing the matching private
key (owner of the building) can open the door and
read the message
War Driving
• the act of searching for wireless networks by a
person in a moving vehicle using a portable
computer or PDA
Story on war driving:
http://www.fbi.gov/news/stories/2004/nove
mber/war_spammer111004
HTTPS
You may have seen HTTPS at the
beginning of the URL while doing
online shopping, banking, etc.
HTTPS stands for Hypertext Transfer
Protocol Secure
It utilizes the SSL/TLS protocol to
provide encrypted communication
and secure identification of a network
web server
Name that topology!
Ring