Transcript ITED 328 Lecture 4 12 Feb 2004

ITED 328 Lecture 4
12 Feb 2004
Loosely covering Chapter 5
Internet and LAN Technology
Section 1 - Networks
A quick over view of networking in
general.


A network is a combination of computer,
cables, NICs, and software.
Each connection is called a "Node".
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Reasons to use a network:
Use of an
application by
multiple users.
Share files.
Transfer files.
Access information
and files.
Share printers ( or
other resources).
Use electronic mail
(email).
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NETWORK DEVICES:
Network file server ( or servers).
Network host computers.
Individual workstations.
Hubs
Routers
Gateways
Bridge
Repeaters
Transmission media.
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More on devices:
Hub- device that connects computers together.
Routers connect two broadcast networks (at layer 3
the Network layer).
Gateways connect multiple computers so they can
access the network it at the same time. Connects
networks that use different protocols( at layer 7, the
gateway layer).
Bridges connect LANS at the data link layer.
Transmission media: fiber optic, coaxial, twisted pair,
also air.
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Network configurations
(a.k.a. topology)
STAR
RING
Bus
Peer to Peer
(how we are going to do our next lab !)
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Network Protocols
A method of coordinating
communications on a network.
Different types

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Low Level PROTOCOLS - no guarantee
data is received.
Mid level PROTOCOLS – Limited control
Higher level PROTOCOLS User has control.
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LOW LEVEL PROTOCOLS
Token Ring is a Local Area Network (LAN) protocol.
The Token Ring protocol was first developed by IBM.
Token Ring is standardized in IEEE 802.5 that was
published in 1985. The protocol deals with the
problem of collision, which is defined as a state were
two stations transmit at the same time. In order to
avoid the situation of collision there was a need to
control the access to the network. This kind of
control is possible by the use of a control
(permission) called token. The token is passed from
one station to another according to a set of rules.
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Token Ring continued…………..
Only the station in possession of the
token is allowed to transmit data. Each
station repeats the data, checks for
errors, and copies the data if
appropriate. When the data is returned
to the sending station, it removes it
from the ring. The token Ring protocol
supports priorities in transmission.
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Token Ring continued…………..
2 ways to implement: Star or Ring
Source
http://www2.rad.com/networks/1996/to
knring/toknring.htm#Topology
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Ethernet
Ethernet is communication over a single cable shared
by all devices on the network. Once a device
attached to this cable, it had the ability to
communicate with any other attached device. This
allows the network to expand to accommodate new
devices without requiring any modification to those
devices already on the network.
Source
http://computer.howstuffworks.com/ethernet2.htm
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FDDI
Fiber Distributed Data Interface
Used to connect two or more LANs over
long distances ( i.e. transcontential).
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MID LEVEL PROTOCOLS
Initiate communications, send and
receive data, can terminate
communications.
NetBIOS, TCP/IP
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High Level Protocols
Client /Server
Unix / Linux LANS
TCP/IP
telnet
ftp
rlogin, rcp,rsh, ping
NFS - Network Files System
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Software used for networks
Novell, Windows NT Advanced Server
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The Seven layers of the OSI
7
6
5
4
3
2

1
Application
Presentation
Session
Transport
Network
Data link layer
(sub layers Logical Link and MAC)
Physical (hardware layer)
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Misc Info
How the data is sent: Frames and
Packets!
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THE INTERNET
IP address 32 bit host address of a computer on the
network
Class A - high bit 0, 7-bit network number, 24-bit
host number. n1.a.a.a 0 <= n1 <= 127
Class B - high 2 bits 10, 14-bit network number, 16bit host number. n1.n2.a.a 128 <= n1 <= 191
Class C - high 3 bits 110, 21-bit network number, 8bit host number. n1.n2.n3.a 192 <= n1 <= 223
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IP Addresses
Dynamic or static IP Address
IP Address
network host subnet
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More Misc Info ……
Domain name or fully qualified domain name
is a way for all the computer in the world to
have a unique name on the internet. (
STARTED by DARPA)
Different domains: *.com *.edu, *.gov,
*.net , *.org , *.mil, *.info , *.biz , *.int
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How to be connected:
DIAL UP via phone and modem
DSL - Digital Subscriber Line
DSS - Direct Satellite Service
Wireless
Broad band - covers frequencies from
audio to video
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Standards to Know of:
IEEE 802.11
IEEE 802.11 has many subsections:
802.11 a is for radio-based LAN protocol
which speaks OFDM at 5GHz, one of the two
wi-fi protocols.
802.11b is wireless local area networks
(WLAN) standard protocol which speaks DSSS
at 2.4GHz. 802.11b is one of the two wi-fi
protocols. It operates at 11 megabits per
second (Mbps).
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802.11 Continued ……
An IEEE wireless local area network
(WLAN) standard protocol, expected to
be approved in June 2003. 802.11g
offers wireless transmission over
relatively short distances at up to 54
megabits per second (Mbps).
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