computer project holidays homework main protocols described

1. Protocols in computer network
As we all know that rules are very
important and required for the smooth
functioning of every institution.
Similarly, in a computer system we
have PROTOCOLS are nothing but the
rules and regulations in the context of
a computer system. They can be
implemented by hardware, software or
a combination of both.
WHAT EXACTLY IS A PROTOCOL?
 Rules and conventions explaining how something must be
done.
 Used to describe how devices can communicate.
 Protocol also defines the format of data i.e. to be
exchanged....

2. TCP/IP
It is the most important protocol consisting of a set of communication
protocols. Transmission control protocol (TCP) and the Internet
Protocol (IP) were the first networking protocol. Its functionality is
organized into four abstraction layers which are used to sort all
related protocols according to the scope of networking involved.
In computer networking, we have a process called Encapsulation which
is used to provide abstraction of protocols and services. It is a method
of designing Modular Communication in which a system is divided into
small parts called modes or logically separate functions in a network
are abstracted from their underlying structures by inclusion or
information hiding. In general, an application (the highest level of the
model) uses a set of protocols to send its data down the layers, being
further encapsulated at each level.

3. The four abstract layers are arranged as follow:
APPLICATION LAYER
It is where applications create user data and communicate this data to
other applications on another or the same host. This uses services
provided by the lower layers, especially the Transport Layer.
TRANSPORT LAYER
It performs host-to-host communications on either the same or
different hosts and on either the local network or remote networks.
INTERNET LAYER
The internet layer has the task of exchanging datagrams across network
boundaries.
LINK LAYER
It defines the networking methods within the scope of the local
network link on which hosts communicate without intervening routers.

4. POP3 IMAP SMTP
POP3 stands for Post Office
Protocol. POP3 allows an email
client to download an email from an
email server. The POP3 protocol is
simple and does not offer many
features except for download. Its
design assumes that the email
client downloads all available email
from the server, deletes them
from the server and then
disconnects. POP3 normally uses
port 110.
SMTP stands for
Simple Mail Transfer
Protocol. SMTP is used
when email is
delivered from an
email client, such as
Outlook Express, to an
email server or when
email is delivered
from one email server
to another. SMTP uses
port 25.
IMAP stands for Internet Message Access Protocol. IMAP shares many
similar features with POP3. It, too, is a protocol that an email client can
use to download email from an email server. However, IMAP includes
many more features than POP3. The IMAP protocol is designed to let users
keep their email on the server. IMAP requires more disk space on the
server and more CPU resources than POP3, as all emails are stored on the
server. IMAP normally uses port 143.

5. VoIP
Voice over IP or VoIP is a methodology and
group of technologies for the delivery of voice
communications and multimedia sessions over
IP networks. It has been implemented in
various ways using both proprietary protocols
and protocols based on open standards.
WORKING OF VoIP
VoIP systems employ session control and signaling protocols to control the
signaling, set up and teardown of calls. They transport audio streams over IP
networks using special media delivery protocols that encode voice, audio, video
with audio codecs, and video codecs as Digital audio by streaming media. Various
codecs exist that optimize the media stream based on application requirements
and network bandwidth; some implementations rely on narrowband and
compressed sheet, while others support high fidelity stereo codecs.
 PSTN (Public Switched Telephone network) is the world's collection of interconnected
voice-oriented public telephone networks, both commercial and government-owned.
 For option 2, no internet is provided because connectivity is dedicated to voice data
which assures high quality calls.

6. RTSP
The Real Time Streaming Protocol (RTSP) is a network control protocol designed
for use in entertainment and communications systems to control streaming
media servers. The protocol is used for establishing and controlling media
sessions between end points. Streaming media is multimedia that is constantly
received by and presented to an end-user while being delivered by a
provider. The transmission of streaming data itself is not a task of RTSP. Most
RTSP servers use the Real-time Transport Protocol (RTP) in conjunction
with Real-time Control Protocol (RTCP) for media stream delivery. However,
some vendors implement proprietary transport protocols. While similar in some
ways to HTTP, RTSP defines control sequences useful in controlling multimedia
playback. While HTTP is stateless, RTSP has state; an identifier is used when
needed to track concurrent sessions. Like HTTP, RTSP uses TCP to maintain an
end-to-end connection and, while most RTSP control messages are sent by the
client to the server, some commands travel in the other direction (i.e. from
server to client).

7. HTTPS
HTTPS, also known as HTTP secure is a protocol for secure communication
over a computer network which is widely used
on internet. The main motivation for HTTPS
is authentication of the visited website and
protection of the privacy and integrity of the
exchanged data. HTTPS creates a secure
channel over an insecure network. This ensures reasonable protection
from eavesdroppers and man-in-the-middle attacks, provided that
adequate cipher suites are used and that the server certificate is verified and
trusted.
How does HTTPS work?

8. DMCP
The Dynamic Host Configuration Protocol (DHCP) is a standardized network
protocol used on Internet Protocol (IP) networks.
When a computer or other networked device connects to a network, the DHCP
client software sends a broadcast query requesting necessary information. Any
DHCP server on the network may service the request. The DHCP server manages
a pool of IP addresses and information about client configuration parameters
such as default gateway, domain name, the name servers, and time servers.
On receiving a request, the server may respond with specific information for
each client, as previously configured by an administrator, or with a specific
address and any other information valid for the entire network and for the time
period for which the allocation (lease) is valid. A client typically queries for this
information immediately after booting, and periodically thereafter before the
expiration of the information. When a DHCP client refreshes an assignment, it
initially requests the same parameter values, but the DHCP server may assign a
new address based on the assignment policies set by administrators.

9. ICMP
The Internet Control Message Protocol (ICMP) is used by network devices, like
routers, to send error messages. ICMP can also be used to relay query messages.
It is assigned protocol number 1. ICMP messages are typically used for
diagnostic or control purposes or generated in response to errors
in IP operations. ICMP errors are directed to the source IP address of the
originating packet.
UDP
UDP stands for User Datagram Protocol .In UDP, the receiver does not
generate an acknowledgement of packet received and in turn, the sender does
not wait for any acknowledgement of packet sent. UDP provides two services not
provided by the IP layer. It provides port numbers to help distinguish different
user requests and, optionally, a checksum capability to verify that the data
arrived intact. UDP is unreliable and connectionless.

10. FTP
The File Transfer Protocol (FTP) is
used to transfer computer files between a
client and server on a computer network. It
is the simplest and most secure way to
exchange files over the internet. FTP is
built on client-server model architecture
and uses separate control and data connections between the client and the
server. FTP users may authenticate themselves with a clear-text sign-in
protocol, normally in the form of a username and password, but can connect
anonymously if the server is configured to allow it. FTP may run
in active or passive mode, which determines how the data connection is
established. In both cases, the client creates a TCP control connection from a
random, usually an unprivileged, port N to the FTP server command port 21.
 In active mode, the client starts listening for incoming data
connections from the server on port M. It sends the FTP command PORT
M to inform the server on which port it is listening. The server then
initiates a data channel to the client from its port 20, the FTP server
data port.
 In situations where the client is behind a firewall and unable to accept
incoming TCP connections, passive mode may be used. In this mode,
the client uses the control connection to send a PASV command to the
server and then receives a server IP address and server port number
from the server, which the client then uses to open a data connection
from an arbitrary client port to the server IP address and server port
number received.

11. ARP
The Address Resolution Protocol (ARP) is a protocol used by the Internet
Protocol (IP) to map IP network addresses to the hardware addresses used by a
data link protocol. The protocol operates below the network layer as a part of
the interface between the OSI network and OSI link layer. It is used the most
commonly used link layer protocol for (LANs) is Ethernet and is used to
support a range of network
layer protocols, including IP.
The address is "resolved"
using a protocol in which a
piece of information is sent by
a client process executing on
the local computer to a server
process executing on a remote
computer. The information received by the server allows the server to uniquely
identify the network system for which the address was required and therefore
to provide the required address. This process ends when the client receives a
response from the server containing the required address. Below is the Format
of an ARP message used to resolve the remote MAC Hardware Address (HA):
It is basically a model that characterizes and standardizes
the communication functions of a telecommunication or
computing system. Its main goal is to operate communication
systems with standard protocols. The model partitions a
communication system into abstraction layers that are
somewhat similar to the ones we learned about earlier.

12. TELNET
Telnet is an application layer protocol used on the Internet or local area
networks to provide a bidirectional interactive text-oriented communication
facility using a virtual terminal connection. User data is interspersed in-
band with Telnet control information in an 8-bit byte oriented data connection
over the Transmission Control Protocol (TCP). It is also known as the first
Internet.
In the old days, you had to physically walk to a server in order to access its data.
Even if the server had the hardware power to do multiple things at the same
time, you were blocked from using it at its full and you had to wait for others to
finish their work first. In many circumstances we couldn't even touch the actual
server.
Telnet brought extraordinary change. Using it meant you could simultaneously
connect multiple users to a single server. In order to connect to the server,
people only needed access to a terminal, which could be the simplest and
cheapest computer available. This computer didn't need to have powerful
hardware, it only needed a network connection and a text based interface.

13. NAME - PRIYA
CLASS - 10-C
ROLL NO. – 26
COMPUTER PROJECT FILE
PROTOCOLS
SUBMITTED TO –
MS. GEETU MA’AM