network

apprehensiveheehawNetworking and Communications

Oct 25, 2013 (3 years and 9 months ago)

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Data
Communications

Networking and Telecommunications

topics for the Business Student



What is the difference between
telecommunications and a network?


TELECOMMUNICATIONS

-

the




of




over public or private networks




NETWORK



t





connected together using


/protocols so that they can work together
.



What are the benefits of a network?

1.
The ability to





with others


is the most popular form of network communications

2.
The ability to share


D






Software


Peripheral devices and other resources


Processing power




What is the most basic way to
differentiate networks?


L




Network (LAN)
--
Connects
computers in relatively



W



Networks (WAN)

--

Connects computers dispersed

among a number of buildings, or

even in different cities.

Biggest WAN =


P




Network (PAN)

--
Wirelessly connecting small

personal devices, really

By

Wireless Topology


Computers are connected by





to
a wireless




(which is directly
connected to a wired LAN)


Must be within a certain number of feet from the access
point to

communicate

wirelessly

(35
-
300 feet

depending on

the technology

being used)

Comparing Wired to Wireless

Wired Network




Communications occur using
a wired media.



F



Tends to be more



L



and hard to
move around (bound to the
wire). Limited by walls,
furniture, infrastructure.



Should be able to easily
handle multiple users



F



work



All of the work tools that you
need probably are available

Wireless Network


Communication occurs using


signals and base station. Limited by
obstructions.



S


: rarely reaches max
speeds that could be available



Inherently


: security features not
turned on: easier to have data packets
captured
.



M


.
Relatively easy to connect to.
Must be within range of hotspot (base station)



One person could monopolize the base
station with huge data transfers: slowness for
everyone
.



Computer can be



, but work
tools needed may not be available when
needed.



Bluetooth vs Wi
-
Fi (802.11)


802.11

802.11b

Provides transmission speeds of up to 11 mbps, 300 feet inside, 800 feet outside.

802.11g

Provides transmission speeds of up to mbps, at a indoor

802.11a

Uses a radio frequency than

standards b & g and other electronic devices
(
kinda

like taking a less crowded route: it will be faster since no one is using it)

802.11n

Still being

developed: expected to
provide transmission speeds over mbps
using MIMO technology ( ):


Allows
for wireless
communications within a




:
2
megabits
per second, up to 30
feet.


Less expensive than Wi
-
Fi chips,



, easier to build
into small devices than run on batteries such as cell phones, palm
-
top computers, and other PDAs.


Called a “personal area network” (PAN) technology.



Business networks use



(Wi
-
Fi/Wireless Fidelity) while
individuals might create their own




network
using B


Bluetooth

Walt Mossberg Chief Technology columnist for the
WallStreet

Journal


Q: I’m wondering about wireless specs for a
laptop. I suspect the “n” version of Wi
-
Fi is best
but “g” is adequate. Any advice would be
appreciated.


A. It depends on how and where you intend to use
your laptop’s wireless connectivity. The “n”
version of Wi
-
Fi can be much faster than “g” and
can have much greater range. However, the speed
difference won’t matter much if your sole use is
connecting to the Internet with a typical home or
public hotspot service, since the maximum speed
of these services is almost always well below “g”
and “n” capabilities. But if you are streaming
video at home or backing up large files wirelessly
among computers and networked hard disks on a
home network, you’d be much better off with “n,”
assuming all devices involved support it. The
same goes for range. In a small apartment, it likely
won’t matter. In a large home, it could.


802.11 wireless standards explained

http://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htm

http://info.cba.ksu.edu/bkovar/wireless.htm

What are Protocols and what is the
difference between them?


Protocol
-

a



that specifies the


as well as the





during transmission



Following a certain






, allows
for interoperability


Interoperability
-

the capability of two or more computer
systems to share data and resources, even though they are
made by different manufacturers



Two primary communications protocols are TCP/IP
and Ethernet


TCP/IP is used for


Ethernet is used by computers in a


to communicate

Ethernet


Ethernet
-

a physical and data layer
technology for LAN networking

Ethernet


Defines the




standards used in a
LAN.



Used to describe the


W




(Co
-
axial, twisted
-
pair, fiber
-
optic)


How bits are physically transmitted using those media


Access control rules


Data transmission speeds



Details







and works on the
principle of




and




Helps insure the compatibility of different devices so that
many people can attach to a common cable.

Transmission Control Protocol/
Internet Protocol


Transmission Control Protocol/Internet
Protocol (TCP/IP)
-

provides the technical







as well as
for large numbers of private network



The TCP/IP protocol suite is made up of over






protocols.


The two





are TCP and IP


TCP provides for


IP provides the

mechanism

TRANSMISSION CONTROL
PROTOCOL / INTERNET PROTOCOL
(TCP / IP)


Allows computers to regardless of
their or hardware.



Transmission Control Protocol


Breaks information into data packets


Reassembles packets when received


Checks for lost packets


Internet Protocol


Each computer given a unique IP address


Used to


209.1.144.212

TCP/IP’s four
-
layer reference model


The layer allows users and applications to access



F protocol (FTP)


Simple protocol (SMTP)



T provides terminal emulation that allows a “ terminal with






” to be able to connect to a
host computer (which will control everything).



H




protocol (HTTP)


Simple network management Protocol (SNMP)


TCP/IP’s four
-
layer reference model


The layer handles



The layer handles the packets (





, etc.)


The layer details how is


through the networking


How Does the Internet Work??

http://www.howstuffworks.com/web
-
server.htm

#1

#2 Browser communicates with to get


#3 Browser
connects to
specific server,
uses GET request
to ask for file you
wish to see.

#4 Server sends
HTML text to
your browser.
HTML tags are
read and page
displayed.

209.1.144.212

What is a VPN?


You can build your own

wired network or you

can



from a

national provider.



Virtual private network

(VPN)
-

a way to use the telecommunication
infrastructure (e.g.,



) to provide secure
access to an organization’s network


T



software is used to create a


connection between two different servers (











).


Data packets are


Network Data Transfer Process: How does it happen?


Network operating system at the source divides the message to be sent
into segments of predetermined length called


Network operating system at the source uses a communications
protocol to


Network Operating System at the source sends packets over the
network.


Packets are routed as necessary through the network depending on the
transmission mediums, transmission signal characteristics and access
control methods.


Network Operating system at the destination receives packets over the
network.


Network Operating system at the destination







by looking at the
communication protocol information. Requests retransmission of any
missing data.

Connecting
Networks

Router

The connection between a LAN and a larger

network is usually accomplished using a

device called
a


.
Routers are used to





. They also
“sit”

(
serving as a gatekeeper both into and out of your
network
). They are intelligent
connecting
devices
that
examine
each packet of data it
receives and then decides which way to send it
onward toward its destination


Router

WAN or Backbone

LAN

LAN

Routers are responsible


for that

messages take from the sending

computer to the destination computer.

Wide Area Network

R

R

R

R

R

R

R

R

R

R

R

R

R

Packet Switched Network

Data is packaged in



for transmission.

Each packet follows



through


the network.

P



occurs
when the
sending computer
divides a message
into a number of
efficiently sized
units called
packets, each of
which contains
the address of the
destination
computer.


WANs

High Speed Backbone

Once a network is linked
to a



, it
becomes part of the
Internet community.

Backbone is

usually a type

of network that has

What are the
different types of
LANs?

P

Each user can share a
portion their
computer’s

with
other LAN users


C

Only resources on
specific computers called
“servers”

can be
shared

Client/Server Networks


Client

-

a computer that is designed to


from a server


Server
-

a computer that is dedicated to providing
information in response to external requests



Client/server network
-

model for applications in
which the takes place on a


, while the
is handled by the

The Client/Server Model

Data Management

Presentation

Business Logic

Storage and management of the data


needed by the application

Actual business rules implemented


The




to the application

Client/Server Model: A Business
View

The different Client/server implementations differ
according to:


1.
Where the processing for the



2.
Where the processing of




occurs


3.
Where the








(DBMS) and





are located

Flexible Applications

Server

Client

Data Management

Business Logic

Presentation

Business Logic

Data Management

Presentation

Business Logic

Any Combination is Possible

Design Server

Client

Production Server

Business Logic

Data Management

Presentation

Data Management

Business Logic

Client/Server Advantages


Application can be structured to match organizational
requirements since it is both


C
an change the implementation of this model as the organization
changes in size since the Client/Server model provides the







to whatever




is




Data access is


regardless of where the data is stored.



Separate programs are more easily maintained and can be
reused.



One





for all of the



and
easier to

Client/Server Disadvantages


All shared resources reside on computers
call “servers”


If a disaster occurs on the server all the data is in
jeopardy


If the server malfunctions,



Expensive


Usually require expensive hardware and extra staff to
manage


Only of client/server costs are tied up in



The remaining is in the form of
-

both
IT professionals and knowledge workers.

Current Events in

Information Technology

Researchers explore scrapping and
rebuilding the Internet


In order to address the problems that were not
envisioned when the Internet was initially created,
some are suggesting rebuilding the Internet using a



approach.



S


The Internet was designed to be open and flexible and all
users were assumed to be trustworthy. Internet protocols
were not designed to authenticate users and their data.
Firewalls and spam filters are now being used to control
security.


Solution: data not passed along until



Mobility


Initially, computers were fixed in location so IP addresses were assigned to
devices in a fixed location. Wireless mobile computing is presenting challenges
related to data flow.


Solution: R




so that addresses are based on the device,
rather than the location.



Ubiquity (also called Pervasive Computing)


When the Internet was first designed, there were relatively few computers
connected to it. The addressing system has become strained due to the
proliferation of personal computers and mobile devices.


Solution: assign






and have those same
devices connected to an addressed gateway, which is then connected to routers
and the rest of the Internet


Result is fewer devices to keep track of and improved efficiency.



These changes may happen over the next 10
-
15 years. They





(expected to cost




as computer hardware and software and Internet
infrastructure are replaced)