This is Networking presentation On sliding window protocol and little about some mix topic like Email, WWW, DNS and dns working, future of w3

1. NETWORKING PRESENTATIONS
Presented By: Pushkar kumar
Presented to: Swati maam
Course: BCA 3rd year (aft.)

2.  Sliding window protocol:
• It is a feature of packet-based data transmission protocols.
• It used for reliable and sequential delivery of data frames, such as in the
data link layer(OSI layer 2) as well as in transmission control
protocol(TCP).
• They are also used to improve efficiency when the channel may include
high latency*.
• Latency: It measures the time, it takes for some data to get to its
destination across the network.

3. • In this protocols, multiple frames can be sent by sender at a time
before receiving an acknowledgement from the receiver.
• The term sliding window refers to the imaginary boxes to hold frames .
It is also known as windowing.
Working Principle:
• In these protocols, the sender has a buffer called the sending
window and the receiver has buffer called the receiving window.
• The size of the sending window determines the sequence number of
the outbound frames.
• If the sequence number of the frames is an n-bit field, then the range
of sequence number that can be assigned is 0 to 2𝑛−1.
• The Sequence numbers are numbered as module 0-n . For example, if
the sending window size is 4, then the sequence number will be 0,
1,2,3,0,1,2,3,0,1 and so on.

4. Sender Receiver
0 1 2 3 4 0 1 2 3 4
0 1 2 3 4 0 1 2 3 4
0 1 2 3 4 0 1 2 3 4
Data 0
Ack 0
Data 1
Ack 1
Moves to right when Ack.
received
Moves to right when Ack.
Sends
For Example: Suppose that we have buffer of sender window and receiver
window of size 2.

5. Types of sliding window:
1. Go- Back-N ARQ(Automatic Repeat reQuest).
2. Selective Request ARQ.
 Go- Back – N ARQ provides for sending multiples frames before receiving the
acknowledgement for the first frame.
 It uses the concept of sliding window, and so is also called sliding window
protocol.
 If the acknowledgement of the frame is not receive within the time period,
all the time period, all frames starting from that frame are retransmitted.
 Selective Repeat ARQ: This protocol also provides for sending multiple
frames before receiving the ack. For the first frame.
 However, here only the erroneous or lost frames are retransmitted, while
the good frames are received and buffered.

6.  E-mail:
 It is define as the transmission of massage on the Internet.
 It is one of the most commonly used feature over communication
network that may contain text, files, images, or other attachments.
 Email message are conveyed through email servers.
 It uses multiple protocols within the TCP/IP suite. For example, SMTP
is a protocol used to send message where other protocols are IMAP
or POP used to retrieve message from a mail server.
 If any one want to login to your mail account, you just need to enter a
valid email address, password, and the mail server used to send and
receive message.

7. Email messages include three components, which are as
follows:
o Message envelope: It depicts the email’s electronic format.
o Message header: It contains email subject line and sender/ recipients
information.
o Message body: It comprises image, text, and other file attachments.
 E-mail Address: Each user of email is assigned a unique name for his
email account. This name is known as E-mail address.
 E-mail is generally of the form username@domainname. For example,
Pushkar@iimmieducatio.com is an E-mail address where Pushkar is
username and iimmieducation.com is domain name.
 The username and the domain are separated by @ symbol.
 E-mail address are not case sensitive.
 Spaces are not allowed in e-mail address.

8. Message Header
The first five lines of an E-mail message is called E-mail header. The header part
comprises of following fields:
 From : It includes the email address of sender who sends the email.
 Date & Time : This field carry actual date and time of when email is send.
 To: In this field we include recipient email address whom we want to send
email.
 Subject: This is known as subject part of email to be send.
 CC : stands for Carbon copy.
 BCC: stands for Black Carbon Copy..

9. Difference between Cc and Bcc
Cc Bcc
A field in Gmail that makes the
recipients see the other receipts
who receive the email
A field in Gmail that makes the
recipients invisible to other
recipients of the email
Stands for carbon copy Stands for blind carbon copy
Allows a recipient to know to
whom a copy of an email has
been sent
Prevents the recipient from
getting to know to whom a copy
of an email has been sent

10. Advantages of Email
There are many advantages of email, which are as follows:
o Cost-effective: Email is very cost effective service to communicate with other as
there are several email services available to individual and organization for free of
cost.
o Speed and simplicity: Email can be composed very easily with the correct
information and contacts.
o Mass Sending: We can send a message easily to large number of people
through email.
Disadvantages of Email
o Impersonal
o Misunderstandings
o Malicious Use
o Accidents Will Happen
o Spam
o Information Overload

11. DNS:
 It is a host name to IP address translation service.
 It is distributed implemented in a hierarchy of name servers.
 It is an application layer protocols for massage exchange between clients and
servers.
 Requirement:
Every host is identified by the IP address but remembering number is very
difficult for the people and also the IP addresses are not domain name to IP
address. So DNS is used to convert the domain name of the website from
their numerical IP address.
Domain name System Architecture:
The Domain name system Architecture consists of Domain Names, Domain
Name Space, Name Servers

12. Domain Names
• Domain name is a symbolic string associated with an IP address.
• There are several domain name available; some of them are generic such as
com, edu, gov, net, ect. While some country level domain names are in, us,
au, za etc.
Domain Name space
• The domain name space refers a hierarchy in the internet naming structure.
Name Server
• Name server contains the DNS database. This database contains of various
names and their corresponding IP addresses.
• Types of Name Server
Following are the three types of Name server that manages the entire Domain
Name System:
• Root Server
• Primary Server
• Secondary server

13. DNS Working
DNS translates the Domain name into IP address automatically. Following are
steps includes in Domain resolution process:
• When we type www.google.com into the browser, it asks the local DNS
server for Its IP address.(local DNS is at Internet services provider(ISP)).
• When local DNS server does not find the IP address of requested domain
name then it forwards the request to the root DNS server and again enquires
about IP address of it.
• The root DNS server replies with delegation that I do not know the IP
address of www.google.com but know the IP address of DNS Server.
• The local DNS server asks the .com DNS server the same question.
• The .com DNS server also replies the same as root DNS.
• Then google.com DNS server replies with IP address of www.google.com
• Now the local DNS sends the IP address of www.google.com to the computer
that sends the request.

14. WWW stands for World Wide Web. It may be define as all the resource and user on
the internet that are using the Hypertext Transfer Protocol (HTTP).
The world wide web is a universe of network-accessible information. In simple word
we can say that World Wide Web is a way of exchange information between
computer on the internet, it is a vast collection of interactive multimedia resources.
Internet and Web is not the same thing: Web uses internet to pass over the
information.
Evolution
World Wide Web was created by Timothy Berners Lee in 1989 at CERN in
Geneva. World Wide Web into existence as a proposal by him, to allow
researchers to work together effectively and efficiently at CERN. Eventually it
become World Wide Web.

15. WWW Operation
WWW works on client-server approach. Following steps explains how the Web
works:
1. User enter the URL (say, http://www.facebook.com) of the web page in the
address bar of web browser.
2. Then Browser requests the Domain Name Server for the IP address
corresponding to www.facebook.com.
3. After receiving IP address, browser sends the request for web page to the web
server using HTTP protocol which specifies the way the browser and web
server communicates.
4. Then web server receives request using HTTP protocol and checks its search
for the requested web page. If found it return it back to the web browser and
close the HTTP connection.
5. Now the web browser receives the web page, It interprets it and display the
contents of web page in web browser’s window.

16. Future
 There had been a rapid development in field of web. It has its impact in
almost every area such as education, research, technology, commerce,
marketing etc. so the future of web is almost unpredictable.
Thank you !!