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Each of the devices on the network can be thought of as a node , and each node has a unique address. The manner in which addresses are assigned willvary from one type of network to another, but in all cases, the address of each device must be unique so as to distinguish it from the other devices.

Addresses are numeric quantities that are easy for computers to work with, but are not easy for humans to remember. Therefore, some networks also providenames that humans can more easily remember than numbers.

Modern networks transfer data using a concept known as packet switching . This means that the data are encapsulated into packets that are transferred fromthe source to the destination. It is necessary to extract the data from one or more packets at the destination and use it to reconstruct the original message.

Communication Protocol

In order for two or more computers connected to a network to be able to exchange data in an orderly manner, they must adhere to a mutually acceptablecommunication protocol. The protocol defines the rules by which they communicate.

Teaching your children to say please and thank you involves teaching them something about a protocol. If they occasionally forget to sayplease, however, they will probably get the cookie anyway.

If a computer protocol requires the participating computers to say please, and they forget to say please, they probably won't get the cookie.

There are many protocols available. For example, the HTTP protocol defines how web browsers and servers communicate and the SMTP protocol defines how emailis transferred (we will write programs that implement part of the HTTP protocol) .

Note here that I have been discussing application protocols that operate at the surface level. We will also be making mention of lower-level protocols thatoperate below the application level. Fortunately, as high-level Java programmers, we don't have to be too concerned about the lower-level protocols.We'll let the systems people worry about them.

Network Layers

Networks are logically separated into layers ranging from the Application Layer at the top to the Physical Layer at the bottom. The technical details of network layering are beyond the scope of this module.Fortunately, you will be able to write useful network programs using Java without understanding the details of network layering.

The Application Layer is the layer that delivers data to the user. The layers below that are involved with getting data from the Application Layer at one end of the conversation to the Application Layer at the other end. For the most part, we will be concerned only with the Application Layer .

Clients and Servers

In these modules, we will be concerned with networked communications that involve client computers and a server computers. How do we know which is which?

For the purposes of our studies, it will be sufficient to say that the client always initiates the conversation, and the server waits and listens for a client to initiate a conversation.

IP, TCP, and UDP

We need to know something about the following acronyms:

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
I'm not good at math so would you help me
what is the problem that i will help you to self with?
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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