Skip to main content

Session Layer

Session Layer(Layer 5): This layer lies between the Transport layer and the Presentation layer. It allows users of different machines to set sessions between them. It establishes, maintains and synchronizes the interaction among communicating devices. It manages communication sessions, i.e. continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes.


The functions of the session layer are:


  • Dialog Control: The session layer allows two systems to enter into a dialog. It allows the communication between the two processes in either half-duplex or full duplex.
  • Synchronization: It allows long transmissions to resume after a checkpointing.

Comments

Popular posts from this blog

Configuring 2 backend servers and a load balancer with HAProxy

A load balancer is a device that distributes the traffic across a cluster of servers. In computing, load balancing improves the distribution of workloads across multiple computing resources, such as computers, a computer cluster, network links, central processing units, or disk drives.As a result, it improves responsiveness and increases the availability of applications.  For load balancing, we need to install LAMP server on backend servers and HAProxy on the load balancer. HAProxy is a free, open source software that provides a high availability load balancer and proxy server for TCP and HTTP based applications that spread requests across multiple servers. Here we will make two backend servers and one load balancer. At two backend servers enter the following commands— $sudo apt-get install apache2 $sudo apt-get install mysql-server $sudo apt-get install php libapache2-mod-php php-mysql $sudo gedit /var/www/html/index.html (Make some changes in t

Devices used in each layer of OSI Model

Pic: Wikipedia 1.Physical Layer- Bits: Hubs, Repeaters, Fibers, Cables, Microwave, Radio, etc. 2.Data Link Layer- Frames: Bridges, 2-Layer Switches, Ethernet, WiFi AP's 3.Network Layer- Packets: Routers, 3-Layer Switches. 4.Transport Layer- Segments: Load Balancers/Firewalls. 5.Session Layer- Data:  Load Balancers/Firewalls/Computers. 6.Presentation Layer- Data: Load Balancers/Firewalls/Computers. 7.Application Layer- Data:  Load Balancers/Firewalls/Computers.

Modes of Data Communication

Modes of Data Communication refers to the direction of data flow from sender to receiver or vice-versa. There are basically three modes of data communication:- 1. Simplex: In this mode the communication is unidirectional . Only one of the two devices on a link can transmit and the other can only receive .i.e data travels in one direction. Example: radio, television, loudspeaker 2. Half-Duplex: In this mode, each device on the link has   the ability to both transmit and receive, each at a time . When one device is sending, the other can only receive and vice versa. Example: walkie-talkie 3. Full-Duplex: In full-duplex mode, both the devices can transmit and receive simultaneously .i.e data can travel in both directions at the same time. Here the communication is bidirectional . Example: Telephone