Transcript Internet Connection Types

Internet Connection Types
•
Connect to the Internet
through:
–
–
–
–
modem
local-area network
cable modem
Digital Subscriber Line
(DSL) connection. DSL is a very
high-speed connection that uses
the same wires as a regular
telephone line.
More definitions of DSL…
• DSL ( Digital Subscriber Line ) is a
method of high-speed data
transfer over ordinary copper
telephone lines. xDSL refers to
different variations of DSL, such as
ADSL, HDSL, SDSL and RADSL.
• *homework: find out what the above acronyms means!
GATEWAY
• A system (hardware-software
combination) that links otherwise
incompatible networks to
communicate with one another.
• The term often refers to the server
computer that links a LAN to the
Internet.
Router
•
Central switching device in a packet-switched network that
directs and controls (routes) the flow of data.
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A traditional router routes packets within a single address
NAT router directs datagrams between different address
realms.
•
NAT router sits on the border between two adress realms and
performs such "transparent routing" by modifying addresses
in IP headers, so that when packets enter another address
realm they can be valid and routed properly.
•
Routers are differentiated from data communications
switches by the ability to perform higher-level functions
necessary to the interconnection of different networks.
NOW, What is NAT???
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Network Address Translation
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NAT (Network Address Translation) is an IETF standard that
enables LANs to use one set of private IP addresses for
internal traffic an another set of IPs for external traffic.
• A NAT device makes all IP address translations where the LAN
meets the WAN.
• NAT permits a large number of LAN users to share one
external IP address,
• and adds some network security, since private IP address
ranges are not routable outside the LAN.
NAT continued
• The following 3 blocks of the IP address space have been
reserved by the Internet Assigned Numbers Authority (IANA)
for private Intranets:
– 10.0.0.0 - 10.255.255.255 (class A, 10/8 prefix)
– 172.16.0.0 - 172.31.255.255 (class B range, 172.16/12 prefix)
– 192.168.0.0 - 192.168.255.255 (class C range, 192.168/16
prefix)
ETHERNET
• Is an IEEE data communications protocol originally
developed for premises and local access networks (IEEE
802.3).
• It was originally developed for peer-to-peer
communications using shared media over relatively
short distances.
• Ethernet has been substantially improved over the
years and now operates in a wide variety of settings.
Ethernet is currently the most widely deployed LAN
protocol in the world.
• Some of the newer variants of the standard include;Fast
Ethernet - Ethernet at 100 Megabits per second.Gigabit
Ethernet (Gig-E) - Ethernet at 1000 Megabits per second.
bandwidth
• Is the amount of data that can be carried in a given
time period over a network.
• More technically, bandwidth is the width of the range
of frequencies that an electronic signal occupies on a
given transmission medium.
• In digital systems, bandwidth is usually expressed as
– bps (bits per second),
– Kbps (Kilobits/second or
– Mbps (Megabits / second).
• In analog systems, it's the number of cycles of
change per second, or hertz.
Homework!!!!
You can do this in the lab
• Read the below sites:
– http://computer.howstuffworks.com/wireless-network2.htm
– http://www.webopedia.com/TERM/8/802_11.html
– http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci783003,00.ht
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