Computer Network Tutorial

Introduction of Computer Network Types of Computer Network Network Topology Computer Networking Architecture Transmission Modes (Data Flow) Basic Networking Devices Integrate Services Digital Network (ISDN)


OSI Model TCP/IP Model

Physical Layer

Digital Transmission Analog Transmission Transmission Media Switching

Data Link Layer

Error detection and Error correction Data Link Control Multiple Access Aloha

Network Layer

Network Layer - Logical Address Address Mapping Unicast Routing Protocol

Transport Layer

Process to Process Delivery User Datagram Protocol Transmission Control Protocol Stream Control Transmission Protocol Session Layer and Presentation Layer

Application Layer

Domain Name System Application Protocol E-mail Cryptography


Classes of Routing Protocols Classification of Routing Algorithms Controlled Access Protocols in Computer Networks Differences between IPv4 and IPv6 Fixed and Flooding Routing Algorithms Advantages and Disadvantages of Fibre Optics Cable APIPA Difference between Active and Passive FTP Fiber Optics and its Types Method of Joining and Fusion of Fiber Optic Cable Define Framing in Computer Network Disadvantages of Computer Network Mesh Topology Diagram in Computer Network Ring Topology in Computer Network Star Topology in Computer Networks 4G Mobile Communication Technology Advantages and Disadvantages of LAN Advantages and Disadvantages of MAN Advantages and Disadvantages of WAN Application Layer in OSI Model Cyclic Redundancy Check Example Data link layer in OSI model Difference between Transport and Network Layer Hamming Code Example Network Layer in OSI Model Session Layer in OSI Model Transport Layer in OSI Model Two Port Network in Computer Networks Uses of Computer Networks What is Computer Network What is Framing in a Computer Network Advantages and Disadvantages of Bus Topology Difference between Star Topology and Bus Topology Subnetting in Computer Network Subnetting Questions and Answers What is Bus Topology What is Network Topology and Types in Computer Networks Access Control in Networking Basic Characteristics of Computer Network Benefits of SOCKS5 Proxy in Computer Networks Computer Network viva Questions Difference between BOOTP and RARP Difference Between Network Topologies and Network Protocols Difference between NFC and RFID Difference Between Point-to-Point Link and star Topology Network Differences Between MSS and MTU Differences Between Trunk Port and Access Port Different Modes of Communication in Computer Networks MIME Protocol in Computer Networks Modes of Communication in Computer Networks Network Attack in Computer Network Port Address in Networking Simplest Protocol in Computer Network Sliding Window Protocol in Computer Network Stop And Wait Protocol in Computer Networks TCP 3-Way Handshake Process in Computer Networks What is a Proxy Server What is APPN What is ICMP Protocol What is Point-to-Point Protocol What is Port Address in Networking What is the HDLC Protocol What is VRRP Protocol Difference Between Analog and Digital Signals Difference Between Hub and Repeater Difference between Repeater and Switch Difference Between Transparent Bridge and Source Routing Bridge Source Routing Bridge in Computer Networks Transparent Bridge in Computer Networks Transport Protocol in Computer Networks Types of CSMA in Computer Networks What is Wired and Wireless Networking Network Security in Computer Network Disadvantages of Extranet Difference Between TELNET and FTP Define Protocol in Computer Networks Guided Transmission Media in Computer Network What is a Gateway in a Computer Network IGMP in Computer Networks LAN Protocols in Computer Networks MAN Meaning in Computer Modulation Techniques in Computer Networks Switching in DCN TCP/IP Applications What is IGMP? What is Modem in Networking What is Non-Persistent CSMA Difference between Cell Splitting and Cell Sectoring Forouzen Computer Network

Session Layer and Presentation Layer

Session Layer and Presentation Layer

Session Layer

The fifth layer is the Session layer in the OSI model, which controls connections between many computers. It manages, establishes, and terminates the session connection between two communication hosts. The figure shows below.

Session Layer and Presentation Layer

Major functions of the Session Layer

  • Dialog control: In the session layer, it permits two systems to enter a dialog that permits the communication between two processes in either half-duplex mode and full-duplex mode.
  • Synchronization: It allows us to incorporate checkpoints into the data stream. For example, suppose the system is sending a message of 1000 bits, it inserts the checkpoints after every 50 bits and to ensure that each 50 bits unit is received and acknowledged individually. In this case, if a crash happens during the transmission of 453 bit, that only needs to be a retransmission of 401 to 453. Previous of 401 bits are not required to re-sent.
  • Token Management: The session layer stops two hosts from attempting the same operation at the same time.

Necessary protocols of the session layer 

  • Remote procedure call protocol (RPC) 
  • Point-to-Point Tunneling Protocol (PPTP)
  • Session Control Protocol (SCP)
  • Session Description Protocol (SDP)

Presentation Layer

The sixth layer is the Presentation Layer in the OSI model. In the Presentation layer, it deals with the syntax and semantics information which exchanges between two systems. The figure shows below.

Session Layer and Presentation Layer

Major functions of the Session Layer

  • Translation: It converts a message to compatible bit-streams before being transmitted. Because various computers use various encoding methods, it is responsible for interoperability between these various encoding methods, which is changing the message into a standard format.
  • Encryption: Encryption means to transform the original message into another form, that will not be readable by others.
  • Compression: In Compression, Reduces the number of bits to be transmitted over the network.