3. Session Layer
• The Session Layer is the 5th layer in the Open System
Interconnection (OSI) model. This layer allows users on
different machines to establish active communications
sessions between them. It is responsible for establishing,
maintaining, synchronizing, terminating sessions between
end-user applications.
4. FUNCTIONS
• Session Layer works as a dialog controller through which
it allows systems to communicate in either half-duplex
mode or full duplex mode of communication.
• This layer is also responsible for token management,
through which it prevents two users to simultaneously
access or attempting the same critical operation.
• This layer allows synchronization by allowing the process
of adding checkpoints, which are considered as
synchronization points to the streams of data.
5. PROTOCOLS
• AppleTalk Data Stream Protocol (ADSP): ADSP is that type of protocol
which was developed by Apple Inc. and it includes a number of features that
allow local area networks to be connected with no prior setup.
• Real-time Transport Control Protocol (RTCP): RTCP is a protocol which
provides out-of-band statistics and control information for an RTP (Real-time
Transport Protocol) session.
• Point-to-Point Tunneling Protocol (PPTP): PPTP is a protocol which
provides a method for implementing virtual private networks.
• Password Authentication Protocol (PAP): Password Authentication
Protocol is a password-based authentication protocol used by Point to Point
Protocol (PPP) to validate users.
6. • Remote Procedure Call Protocol (RPCP): Remote Procedure
Call Protocol (RPCP) is a protocol that is used when a computer
program causes a procedure (or a sub-routine) to execute in a
different address space without the programmer explicitly coding
the details for the remote interaction.
• Sockets Direct Protocol (SDP): Sockets Direct Protocol (SDP) is
a protocol that supports streams of sockets over Remote Direct
Memory Access (RDMA) network fabrics.
8. • The presentation layer is located at the sixth level of the
OSI model, it is responsible for the delivery and formatting
of information to the application layer for further
processing or display.
• This type of service is needed because different computer
architectures use different data representations.
• In contrast to providing transparent data transport at the
fifth level, the presentation layer handles all issues related
to data presentation and transport, including translation,
encryption, and compression.
9. FUNCTIONS
• Presentation layer format and encrypts data to be sent
across the network.
• This layer takes care that the data is sent in such a way
that the receiver will understand the information (data)
and will be able to use the data efficiently and effectively.
• This layer manages the abstract data structures and
allows high-level data structures (example- banking
records), which are to be defined or exchanged.
10. PROTOCOLS
• Apple Filing Protocol (AFP): Apple Filing Protocol is the
proprietary network protocol (communications protocol) that offers
services to macOS or the classic macOS.
• Lightweight Presentation Protocol (LPP): Lightweight
Presentation Protocol is that protocol which is used to provide ISO
presentation services on the top of TCP/IP based protocol stacks.
• NetWare Core Protocol (NCP): NetWare Core Protocol is the
network protocol which is used to access file, print, directory, clock
synchronization, messaging, remote command execution and
other network service functions.
11. • Network Data Representation (NDR): Network Data
Representation is basically the implementation of the presentation
layer in the OSI model, which provides or defines various primitive
data types, constructed data types and also several types of data
representations.
• External Data Representation (XDR): External Data
Representation (XDR) is the standard for the description and
encoding of data.
• Secure Socket Layer (SSL): The Secure Socket Layer protocol
provides security to the data that is being transferred between the
web browser and the server.
13. • The Application Layer is topmost layer in the Open
System Interconnection (OSI) model.
• This layer provides several ways for manipulating the data
which actually enables any type of user to access network
with ease.
• This layer is basically highest level of open system, which
provides services directly for application process.
14. FUNCTIONS
• Application Layer provides a facility by which users can
forward several emails and it also provides a storage
facility.
• This layer allows users to access, retrieve and manage
files in a remote computer.
• It allows users to log on as a remote host.
• This layer provides access to global information about
various services.
15. PROTOCOLS
• TELNET: Telnet stands for Telecommunications Network. This protocol is
used for managing files over the Internet. It allows the Telnet clients to
access the resources of Telnet server. Telnet uses port number 23.
• DNS: DNS stands for Domain Name System. The DNS service translates the
domain name (selected by user) into the corresponding IP address. For
example- If you choose the domain name as www.abcd.com, then DNS must
translate it as 192.36.20.8 (random IP address written just for understanding
purposes). DNS protocol uses the port number 53.
• DHCP: DHCP stands for Dynamic Host Configuration Protocol. It provides IP
addresses to hosts. Whenever a host tries to register for an IP address with
the DHCP server, DHCP server provides lots of information to the
corresponding host. DHCP uses port numbers 67 and 68.
16. • FTP: FTP stands for File Transfer Protocol. This protocol helps to transfer
different files from one device to another. FTP promotes sharing of files via
remote computer devices with reliable, efficient data transfer. FTP uses port
number 20 for data access and port number 21 for data control.
• SMTP: SMTP stands for Simple Mail Transfer Protocol. It is used to transfer
electronic mail from one user to another user. SMTP is used by end users to
send emails with ease. SMTP uses port numbers 25 and 587.
• HTTP: HTTP stands for Hyper Text Transfer Protocol. It is the foundation of
the World Wide Web (WWW). HTTP works on the client server model. This
protocol is used for transmitting hypermedia documents like HTML.
17. • NFS: NFS stands for Network File System. This protocol allows
remote hosts to mount files over a network and interact with those
file systems as though they are mounted locally. NFS uses the
port number 2049.
• SNMP: SNMP stands for Simple Network Management Protocol.
This protocol gathers data by polling the devices from the network
to the management station at fixed or random intervals, requiring
them to disclose certain information. SNMP uses port numbers
161 (TCP) and 162 (UDP).
19. • We’ll be taking a look at the role of communication pattern
in keeping us stuck in relationship problems.
• This is the final post in a series that looks at the process
by how we get stuck in arguments.
• Other posts in this series have explored the role that
personal differences, emotional sensitivities, and external
stressors play in creating and maintaining relationship
problems
21. What is TCP/IP?
• TCP/IP stands for Transmission Control Protocol/Internet Protocol,
is a standard Internet communications protocols that allow digital
computers to communicate over long distances.
• TCP is the component that collects and reassembles the packets
of data, while IP is responsible for making sure the packets are
sent to the right destination.
• The TCP/IP model is a concise version of the OSI model. It
contains four layers, unlike seven layers in the OSI model.
23. Network Access Layer
• This is the bottom-most layer of the TCP/IP model architecture
• It is a combination of the Data Link and Physical Layer of the OSI
model
• The physical transmission of data takes place at this layer
• Once the frames are transmitted by a network, encapsulating the
IP datagram into these frames is done in this layer
• Also, the mapping of IP address into physical address is done
here
• Mainly, the function of this layer is to transmit the data between
two devices, connected in a network
24. Internet Layer
• It is the second layer of the TCP/IP model and this layer is
parallel to the Network Layer of the OSI Model, in terms of
the structure
• Sending the data packets to their destination network is
the main function of the Internet layer
• The logical transmission of data takes place at this level
25. Host-To-Host Layer
• This layer is parallel to the transport layer of the OSI Model
• The error-free delivery of data is the main function of this layer
• There are two main protocols present in this layer:
-TCP: Another integral part, the Transmission Control Protocol is a
reliable communication protocol. It manager the flow of data, i.e. the
sequence and segmentation of the data
-UDP: It is a connection-free protocol which makes it cost-effective
but less reliable.
26. Application Layer
• The topic three layers of the OSI Model: Application, Presentation and
Sessions, when combined together, they perform similar functions as the
Application Layer of the TCP/IP model
• node-to-node communication based on the user-interface occurs here
• Multiple protocols are present in this layer, a few common ones have been
mentioned below in brief:
-HTTP: Hypertext Transfer Protocol is used to manage the communication
between the server and web browsers
-NTP: Network Time Protocol can set one standard time source in our computer,
which enables sync between the server and the user
-TELNET: Telecommunication Network is used to have access to files present of
the Telnet network and manage them on internet
-FTP: File Transfer Protocol, as the name suggests allows easy transferring of
files
