Network Programming, TFRS, TCP, UDP,TFMCC

8/12/2019 Network Programming, TFRS, TCP, UDP,TFMCC

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Network ProgrammingAssignment #01

Name:Muhammad Shan Anwer MalikRegistration No:SP11-BCE-034Submitted to: Amber Madeeha ZebSubmission Date: 28th Feb 2014


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What is network Application?

Answer:Network applications use a client-server architecture, where

the client and server are two computers connected to the network. The

server is programmed to provide some service to the client.

The client is typically a desktop, laptop or portable device like an

Apple iPhone. The server can be any of these, but is typically a

computer in a data center.

In most (though not all) network applications, the client computer

runs a Web client program like Firefox or Internet Explorer, and the

server runs a Web server program likeApacheor Internet Information

Server. Shared data would be stored on the server or a computer it

could access.

Note that the user of a network application might be a computer, not a

person. For example, a computer might query the server in a vendingmachine, checking to see if it was low on Doctor Pepper or Coke.

Search engine companies like Google run client programs that

constantly scan the Web, checking for new pages which can be indexed.

Any application which makes use of network to do its functionalities

is called network application. The network may be a small network or

it may be a network of networks called the internet. Network

application do their functionalities according to some protocols. A

protocol is the special set of rules that end points in a

telecommunication connection use when they communicate. Protocols

specify interactions between the communicating entities.

Two well known examples of network applications are:

Skype:

Skype is a software program of IM, it allows users to make telephone

calls over the Internet to other Skype users free of charge and to

landlines and cell phones for a fee. Additional features include

instant messaging, file transfer, short message service, video

conferencing and its ability to circumvent firewalls.

Skype uses a proprietary Internet telephony (VoIP) network,it use TCP

and UDP to communicate.

Dropbox:

Dropbox is a file hosting servicethat offers cloud storage, file

synchronization, and clientsoftware.

Dropbox uses SSL (for data transfers) and AES-256 for storage.
http://en.wikipedia.org/wiki/File_hosting_servicehttp://en.wikipedia.org/wiki/Cloud_storagehttp://en.wikipedia.org/wiki/File_synchronizationhttp://en.wikipedia.org/wiki/File_synchronizationhttp://en.wikipedia.org/wiki/Client_(computing)http://en.wikipedia.org/wiki/Client_(computing)http://en.wikipedia.org/wiki/File_synchronizationhttp://en.wikipedia.org/wiki/File_synchronizationhttp://en.wikipedia.org/wiki/Cloud_storagehttp://en.wikipedia.org/wiki/File_hosting_service


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What are various protocols for development of network applications?

Answer:

First let ask ourselves a few questions.

What is a protocol?

A protocol is the special set of rules that end points in a

telecommunication connection use when they communicate. Protocols

specify interactions between the communicating entities.

There are a lots of protocols for the development of network

applications. Many of them are in the development stage like TFRC,

TFMCC and some of them already a standard and is used by many network

applications like TCP, VOIP, UDP, HTTP, FTP, IPv4, IPv6 etc. The ones

which are very important in the world of socket programmingare TCP/IP

and UDP/IP. The structures of these protocols are used almost

everywhere in the world of socket programming and the ones which are

becoming popular when it comes to socket programming these days are

TFRCand TFMCC.

Some of the very important protocols are mentioned below:

IP: The Internet Protocol (IP) is the method or protocolby

which datais sent from one computer to another on the Internet. Each

computer (known as a host) on the Internet has at least oneIP

addressthat uniquely identifies it from all other computers on the

Internet.

When you send or receive data (for example, an e-mail note or a Webpage), the message gets divided into little chunks called packets.

Each of these packets contains both the sender's Internet address and

the receiver's address.

TCP: TCPis a connection oriented protocol which is used to reliably

send data making use of the sequence numbers and acknowledgements to

send and receive data between two network applications. TCP makes use

of IP called the internet protocol to send and receive data. The

sessions are established using the socket address which is composed of

port number of individual applications and the IP address of the

communicating devices. TCP make sure that the data units are

transferred reliably while IP is makes sure that actual and desired

receiver gets the data.

For example, when an HTMLfile is sent to you from a Web server, the

Transmission Control Protocol (TCP) program layer in that server

divides the file into one or more packets, numbers the packets, and
http://searchnetworking.techtarget.com/definition/protocolhttp://searchdatamanagement.techtarget.com/definition/datahttp://searchwindevelopment.techtarget.com/definition/Internethttp://searchcio-midmarket.techtarget.com/definition/hosthttp://searchwindevelopment.techtarget.com/definition/IP-addresshttp://searchwindevelopment.techtarget.com/definition/IP-addresshttp://searchsoa.techtarget.com/definition/HTMLhttp://whatis.techtarget.com/definition/serverhttp://whatis.techtarget.com/definition/serverhttp://searchsoa.techtarget.com/definition/HTMLhttp://searchwindevelopment.techtarget.com/definition/IP-addresshttp://searchwindevelopment.techtarget.com/definition/IP-addresshttp://searchcio-midmarket.techtarget.com/definition/hosthttp://searchwindevelopment.techtarget.com/definition/Internethttp://searchdatamanagement.techtarget.com/definition/datahttp://searchnetworking.techtarget.com/definition/protocol


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then forwards them individually to the IP program layer. Although each

packet has the same destination IP address, it may get routed

differently through the network. At the other end (the clientprogram

in your computer), TCP reassembles the individual packets and waits

until they have arrived to forward them to you as a single file.

UDP: UDP or User Datagram Protocol is a connectionless non reliable

protocol which is used usually used for the most Real Time

applications. Like TCP,UDP is also very important in the world of

socket programming which shows its importance for the development of

network applications. UDPis faster than TCPbecause it adds less

overheads as oppose to TCPwhich used sequence numbers and

acknowledgements which slows down the speed of data transfer. It is

mainly used for Real Time applications like online streaming, Voice

over internet protocol etc. because in real time application even if

you miss a few packets of data it does not make much of a problem. Forexample in a network application where a live streaming of a video is

involved if one of the frame gets missed during the transmission it

does not create any sort of a problem or headache for the person

watching the live streaming.

TFRC: TCP-Friendly Rate Control (TFRC) is a congestion

controlmechanism designed for unicastflows operating in an Internet

environment and competing with TCPtraffic. The goal is to compete

fairly with TCP traffic on medium timescales, but to be much less

variable than TCP on short timescales.

TCP congestion controlworks by maintaining a windowof packets that

have not yet been acknowledged. This window is increased by one packet

every round trip timeif no packets have been lost, and is decreased

by half if a packet loss is detected. Thus TCP's window (and hence

throughput) is a function of the losses observed in the network and

the round trip time experienced by the flow.

The idea behind TFRC is to measure the loss probability and round trip

time and to use these as the parameters to a model of TCP throughput.

The expected throughput from this model is then used to directly drive

the transmit rate of a TFRC flow.

TFMCC: TFMCC is an equation-based multicast congestion control

mechanism that extends the TCP-friendly TFRCprotocol from the unicast

to the multicast domain. The key challenges in the design of TFMCC lie
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in scalable round-trip time measurements, appropriate feedback

suppression, and in ensuring that feedback delays in the control loop

do not adversely affect fairness towards competing flows

FTP:FTPor file transfer protocol is a commonly used protocol for

exchanging files over any network that supports the TCP/IP protocol

such as the Internet or an intranet. There are two computers involved

in an FTP transfer: a server and a client. The FTP server, running FTP

server software, listens on the network for connection requests from

other computers. The client computer, running FTP client software,

initiates a connection to the server. Once connected, the client can

do a number of filemanipulation operations such as uploading files to

the server, download files from the server, rename or delete files on

the server and so on. Any software company or individual programmer is

able to create FTP server or client software because the protocol is

an open standard. Virtually every computer platform supports the FTP

protocol. This allows any computer connected to a TCP/IP based network

to manipulate files on another computer on that network regardless of

which operating systems are involved if the computers permit FTP

access.

SSL: Another protocol used by network applications typically a Web

Browser is SLL.The Secure Socket Layer (SSL) and Transport Layer

Security (TLS) is the most widely deployed security protocol used

today. It is essentially a protocol that provides a secure channel

between two machines operating over the Internet or an internalnetwork. In todays Internet focused world,the SSL protocol is

typically used when a web browser needs to securely connect to a web

server over the inherently insecure Internet.

HTTP: Short for HyperText Transfer Protocol, HTTP is a set of

standards that allow users of the World Wide Web to exchange

information found on web pages. When wanting to access any web page

enter http:// in front of the web address, which tells the browser to

communicate over HTTP. For example, the full URL for Computer Hope is

http://www.google.com. Today's modern browsers no longer require HTTP

in front of the URL since it is the default method of communication.

However, it is still used in browsers because of the need to access

other protocols such as FTP through the browser.


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SMTP:

Mail delivery from a client application to the server, and from an

originating server to the destination server, is handled by the Simple

Mail Transfer Protocol (SMTP).

The primary purpose of SMTP is to transfer email between mail servers.

However, it is critical for email clients as well. To send email, the

client sends the message to an outgoing mail server, which in turn

contacts the destination mail server for delivery. For this reason, it

is necessary to specify an SMTP server when configuring an email

client.

One important point to make about the SMTP protocol is that it does

not require authentication. This allows anyone on the Internet to send

email to anyone else or even to large groups of people. It is this

characteristic of SMTP that makes junk email or spam possible. Modern

SMTP servers attempt to minimize this behavior by allowing only known

hosts access to the SMTP server. Those servers that do not impose such

restrictions are called open relay servers.

Telnet:

Telnet is a user command and an underlying TCP/IPprotocolfor

accessing remote computers. Through Telnet, an administrator or

another user can accesssomeone else's computer remotely. On the

Web, HTTPand FTP protocols allow you to request specific files from

remote computers, but not to actually be logged on as a user of that

computer. With Telnet, you log on as a regular user with whatever

privileges you may have been granted to the

specific applicationand dataon that computer.
http://searchnetworking.techtarget.com/definition/TCP-IPhttp://searchnetworking.techtarget.com/definition/protocolhttp://whatis.techtarget.com/definition/accesshttp://searchwindevelopment.techtarget.com/definition/HTTPhttp://searchsoftwarequality.techtarget.com/definition/applicationhttp://searchdatamanagement.techtarget.com/definition/datahttp://searchdatamanagement.techtarget.com/definition/datahttp://searchsoftwarequality.techtarget.com/definition/applicationhttp://searchwindevelopment.techtarget.com/definition/HTTPhttp://whatis.techtarget.com/definition/accesshttp://searchnetworking.techtarget.com/definition/protocolhttp://searchnetworking.techtarget.com/definition/TCP-IP


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How the importance of network applications increase with the present

trends in technologies?

Life has been made simple and world has been made a pleasurable place

by the advent of the networks and computers. We could not imagine a

day without Internet.

We are presently living in a world where technology changes many

folds within a few days or we can easily say that trends in

technologies gets changed in the blink of an eye.

Internet Banking has changed the banking industry itself and it

is no longer confined to the branches were one has to approach the

bank in person, to withdraw cash or deposit a cheque or request a

statement of accounts. It allows customers to conduct financial

transactions on a secure way. Electronic Bill Payment and Fund

transfer between Customers is made easier.

Introduction of intelligent and high tech gadgets including

mobile phones computers are putting their effect on the market of

network applications. The mobility introduced in devices and the

trends of cheap technology for everyone has poured technology in the

pocket of every individual. In these circumstances it is difficult to

find a person who does not have an idea of the importance of network

applications.

E-education is also known as e-learning and online education has

created a revolution in education. In this competing world the

students have to learn a lot. Everything cannot be taught by a teacheror in school. To face big challenges in life students take up extra

learning which can be done thorough computers. Communication plays a

pivotal role in our life. Communicating with the people overseas was a

Herculean task before the arrival of computers. Today just by a click

we can communicate directly with the people in any part of the globe.

Computer today have become very user friendly even a 3 year old kid

can operate it.

Without network applications the communication between

individuals is impossible, the communication using network

applications plays the backbone role in most of the businesses aroundthe world. The network applications have become the part of our lives

and can be considered as basic needs of humans these days. Take the

example of apps like whatsapp, viber, skype, facebook app, gmail,

google drive, dropbox, filezilla and the list goes on and on. A few

apps just mentioned can simply explain the importance of network

applications alone. The introduction of high speed internet has


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introduced new trends of streaming videos, songs etc. Downloading

files have become quicker than going to the market and buying a DVD.

Technologies become old within days by the introduction of new

technologies. In recent past we used to buy floppy disks to get a

small amount of space which was in KBs and now we have hard drives

which are in sizes of tera, peta and sometimes exa bytes which are

1/3rd of the sizes of the floppy disks. In the recent past we used to

connect to the internet using dialup connections which were like

54Kbps and now we can have download speeds in Giga bytes. Situations

like this have made world a big market for the developers of network

applications. There is no other field these days which has more

business and job opportunities than network applications development.

Often you will hear techno and even fresh graduates and students

talking about the trends of becoming applications developer or web

designer or networking expert. The trends have changed so quickly that

the world is stunned. Internet through the use of differenttechnologies is the pioneer in the latest changes in the trends of

technologies. Becoming a network application developer seems to be the

best option and can be putted on the top of the list. Network

applications plays such a vital role that our banks, educational

institutes, individuals and even defense are making use of them for

their benefits and progress.


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Explain the working of at least three different network applications.

EMAIL:

Working:Email is delivered using a client/server architecture. An

email message is created using a mail client program. This program

then sends the message to a server. The server then forwards the

message to the recipient's email server, where the message is then

supplied to the recipient's email client.

To enable this process, a variety of standard network protocols allow

different machines, often running different operating systems and

using different email programs, to send and receive email.

Mail delivery from a client application to the server, and from an

originating server to the destination server, is handled by the Simple

Mail Transfer Protocol (SMTP).

The primary purpose of SMTP is to transfer email between mail servers.

However, it is critical for email clients as well. To send email, the

client sends the message to an outgoing mail server, which in turn

contacts the destination mail server for delivery. For this reason, it

is necessary to specify an SMTP server when configuring an email

client.

One important point to make about the SMTP protocol is that it does

not require authentication. This allows anyone on the Internet to send

email to anyone else or even to large groups of people. It is this

characteristic of SMTP that makes junk email or spam possible. Modern

SMTP servers attempt to minimize this behavior by allowing only known

hosts access to the SMTP server. Those servers that do not impose such

restrictions are called open relay servers.

There are two primary protocols used by email client applications to

retrieve email from mail servers: the Post Office Protocol (POP) and

the Internet Message Access Protocol (IMAP).


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SKYPE: Skype, like many other VoIP (Voice over Internet Protocol)

clients available, has changed the way we think about communication

and keeping in touch with loved ones over great distances.

Working: Skype used Voice over internet protocol which uses internet

for its application. VOIP makes use of the SIP to make its messages in

the form of packets. VOIP use of the same network which we use for

email and web surfing to send the packets.

VIOP utilizes the resources so efficiently to send text, voice, images

and even likes videos in high quality.

Computers or special hardware devices like Skype phones are used to

send and receive message packets which are send over the internet

making use of the IP. The voice signal which is analog gets samples,

quantized and encoded into digital. The digital signal is then passed

onto the compressor which compresses the signal so that it could be

sent even using a slower connection.

The digital signal is then derivated into small message parts so that

they could be fixed in packets. Then the destination and source

headers are putted onto the packets so that they could be sent over

the internet.

The receiving end must reconstruct the packets sequentially for ideal

reproduction, which does not happen on most public networks, which are

prone to congestions during peak hours. Latency and packet loss can

render the receiving end to be unable to reconstruct the completeaudio stream resulting in blank audio space for short periods.

Transfer of files:Transferring files by making the use of internet is

another very important application of networks. In recent past we

would only use networks to transfer files within a local network. But

due to the evolution or introduction of high speed internet and file

transfer protocols it is possible for us to send huge files over the

internet

Working:

FTPor file transfer protocol is a commonly used protocol for

exchanging files over any network that supports the TCP/IP protocol

such as the Internet or an intranet. There are two computers involved

in an FTP transfer: a server and a client. The FTP server, running FTP

server software, listens on the network for connection requests from
http://www.makeuseof.com/tags/skypehttp://www.makeuseof.com/tags/skype


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other computers. The client computer, running FTP client software,

initiates a connection to the server. Once connected, the client can

do a number of filemanipulation operations such as uploading files to

the server, download files from the server, rename or delete files on

the server and so on. Any software company or individual programmer is

able to create FTP server or client software because the protocol isan open standard. Virtually every computer platform supports the FTP

protocol. This allows any computer connected to a TCP/IP based network

to manipulate files on another computer on that network regardless of

which operating systems are involved if the computers permit FTP

access.

Documents

Network Programming, TFRS, TCP, UDP,TFMCC