Nice Place

T he top Application Layer of the OSI Reference Model is responsible for making a request to access the information resource - a Computer. With the Session Control Layer,  the access to information resource is performed.  The link of the user Computer ( featured in Application Layer) is established with a Computer ( a Computer that's part of the Session and located at the other end ) that can provide information to the user.  The Computer that's located at the other end comes in the picture as a result of activities that are directed by the Session Control Layer. ____________________________________ Note: It must be noted that a Session underlines the existence of at least two objects. In a Session - the  objects can speak  ( transmit ) or listen ( receive ). When one speaks, the other listens and vice vice versa. _____________________________________ In other words, with the help of the Session Control Layer, connection establishment with a Computer that stores...

T he Presentation Control Layer is a part of the OSI Reference Model. It is the second Layer from the top.  This Layer provides services to the Application/User Layer that lies above.  The presentations to the Application/User Layer are controlled by the Presentation Control Layer. Exchange of information occurs between the Application/User Layer and the Presentation Control Layer. The Application/User Layer requires to be supported with  suitable Data. The Presentation Control Layer supports the Application/User Layer to perform interpretation of Data. The support required by the Application/User Layer to perform interpretation arises because of different forms of Data.  Yes, a piece of Data can be represented in various ways. The various forms of Data present a variety of Data before us. It is to mention that the Application/User Layer is presented with Computer Program and Data. The Presentation Control Layer is responsible for these presentations. Computer Progra...

Circuit Switching is the simplest way in which Computer-to-Computer communication is achieved. The basic elements of Circuit Switching are: ( A ) Computers or Nodes ( B ) Communication Line Data transmitted by a Computer is carried over the Communication Lines. Communication Lines deliver  transmitted data to the receiver ( a Computer). Once a Computer is ready to transmit data, a Communication Line is established. This Line connects the transmitter  to the receiver. _________________________ //Data Directed by Digital Transmitter// //Travel Swiftly to Thankful  Receiver// _________________________ Now, the actual communication begins. The data to be transmitted is divided into Blocks. The Transmitter sends the Blocks on a Communication Line. The Blocks are sent in order.  _____________________________ //Data Sent Block by Block// //Receiver Is the Place to Flock// _____________________________ When all Blocks reach the receiver, the Communication Line  is relea...

A message is a piece of information. It is not communicated in real time. Messages are stored in a storage medium as Message Queues.  Messages are forwarded using Computer Systems. Forwarding messages helps to convey the content to the other end. The forwarded Messages Queue up on the receiver side. We can say Message is an alternative to real time dialogue.  Because it is useful and wise Message Queues are supported. The Queue can be used as per the requirement. Message based communication is a requirement of modern technology. The advanced techniques of communication and data handling have given us the concept of Message Queue. Message Queue is a place where a number of Messages are kept waiting. Message Queues are very helpful as a Message can be picked anytime from these Queues. It is not necessary that incoming Messages be handled immediately.  Whenever there is a requirement, the information that is in the Message Queue can be used. So, a Queue of Messages can be us...

Network Protocol is a set of rules ( guidelines ) to help movement of information on a network. These rules have been given the form of agreement. We are happy that an agreement has materialized to help communication. We are talking about Computer-to-Computer communication.  Indeed Network Protocol lends a helping hand, when information exchange between Computers is performed.  The Network Protocol is available in standardized form. Those interested have worked to provide ways to let Computers communicate. The work product called Protocol is available with us. It serves to benefit when the Protocol is accepted as a guideline by the Computers willing to communicate. The rules specified by Network Protocol serve to guide. It is very essential to follow the guidelines. The follow up  of  Network Protocol guarantees successful communication.  Yes, the success of Computer-to-Computer communication is determined by the Protocol follow up. The Computers that communicat...

  A distribution of Computers may serve as a grid for a group or Cluster of Computer Applications. In the Cluster of Computer Applications the Applications are similar in many ways.  The Applications forming the Applications Cluster are distributed across Computers located at different locations. These locations are specified. We cannot talk about any location. Actually, the Cluster of Applications is supported by an arrangement of Computers. This arrangement of Computers is systematized using Distributed Architecture. Applications are scaled or measured. Such measurement is performed to know if an Application can become a  member of a group.  Applications that are measured or scaled to be similar are grouped. The measurement results from careful observations. Statistical analysis is part of such recording of observations.  A huge size of data resulting from statistical analysis of Applications is very attentively studied. The results of such studies unfold many...

Interface Message Processor ( IMP ) is a special purpose Computer. The Processor plays a vital role in Host-to-Host communication. IMP is placed between Host Computers.  IMP helps Hosts to exchange information. IMPs ( Interface Message Processors ) form a group. The group dedicates itself towards reliable transmission of Packets. _________________________ Note: An Interface Message Processor can be supposed to have a face. Firstly this supposed face of IMP is in the direction of the first Host, which sends the  message. Secondly, this face is turned towards the other Host.  Now, the IMP,  with its face turned around, communicates with this other Host.  Transformed message from IMP is communicated to this Host. __________________________ Message ( a piece of information ) sent from the Host ( source of information  ) is transformed into Packets. Transformation of the message into Packets is performed by an IMP. These Packets are forwarded to the receiver H...

Wide-Area Network is a Network of Computers spread across cities,  countries, continents, and the world. The Network is present over a wide area indeed. WAN can be thought to be an information system. This information system is based on Computers. These Computers are somehow connected. A LAN ( Local Area Network ) may be connected on WAN ( Wide-Area Network). LANs are marked by Personal Computers ( PCs ) or microcomputers. These Personal Computers ( PCs ) become a part of WAN. Mainframe Computers may also be connected on WAN. WAN supports Mainframe Computers as well. WAN Computers use communication media to connect with each other. Communication media is used to share information. Communication media supported by WAN are: A ) Lines or Trunks  B ) Satellites  C) Microwave D) Medium and Long Range Radio Waves WAN communication takes time. Information travels from one Computer to another. There is some delay in this communication process. It is natural because such activity ...

Application of Power can make a thing rise. Indeed, the use of power makes sense. It gives simplicity in our attempt to represent numbers. It leads to achievement of mathematical solutions very easily and quickly. ______________________________ Note: Power is also called exponent. ______________________________ A number is given a power when it is needed. It can be said that the number has been raised to a numeric value. Any number that is given power as '0' is equal to '1'. In Mathematics '2' to the power '4' means that the number '2' must be multiplied by itself '4' times. This is written as 2^4 , or 2 × 2 × 2 × 2, which equals 16. With a power a number becomes more powerful. Power is a type of qualification for a number. The task of writing numbers has simplified and become easy with the Power concept.  Large numbers are difficult to write. Another point is that such numbers are difficult to read. The  Power concept is really very help...

Packet means a segment of information. This segment of information has a size. Yes, the size is that of the information that lies in the packet. We know that the size of information is expressed in bytes.  Information travels through Networks in the form of packets. In a particular collection all the packets have equal size. If we talk of packets elsewhere, then size may be different.  Packets can be sent over telecommunications lines. Such activities result in assured delivery of packets to the receiver. Yes, such transportation over physical links is reliable.  At a time only one packet can be sent over a telecommunications line. When the line becomes free, the next packet can be sent. When a packet is sent over a communication line, communication may succeed or fail. The success or failure of the communication process is related to transmission of previous and subsequent packets. This is true in cases where communication uses physical connections such as telecommunicat...

Multi-Tier Architecture of Computers is focused on multi-level arrangement of computing units. It is our goal to study how Computers are used levelwise. According to capacity and requirements we place Computers in three different tiers. The different requirements that should be met primarily by the Computers at three levels are: 1 ) 1st Tier: Satisfactory Speed and Memory Capacity  2 ) 2nd Tier: High Processing Speed 3 ) 3rd Tier: Large Storage ____________________________ First Tier: The Computer at the First Tier starts the communication process. In the First Tier there is a user Computer. It is also called Client Computer ( Thin Client). The Client needs service. It frames its requirement(s). The requirement is forwarded to the Computer at the Second Tier. After forwarding its requirement, the Client Computer waits for the response ( reply ). The response ( reply ) is expected from the Second Tier Computer to which service request has been forwarded.  ______________________...

A Communication Subnetwork ( Subnet ) is a typical subpart of a Network. The Subnetwork Computers are of high capacity. The subnetwork activities are carefully monitored. Advanced Computers are used as nodes. These are called Hosts. Such Computers are interconnected with communication links forming a Communication Subnetwork.  Subnetwork Computers have high speed and large storage. Such Computers may have additional processors, besides the main processing unit. The data to be processed may be of complex nature. The size of data handled here is large. Intensive operations are performed to process data. It must be said that Advanced Processors are of much use here. Inflow of data to the Communication Subnetwork from outside causes the size of data to be large. Data from outside  has to be handled by the Subnetwork. The memory capacity of Subnetwork Computers is well suited for large size data. Subnetwork links may distribute the inflow of data to several Subnetwork Computers. Th...

Local-Area Networks ( LANs ) are restricted to a small area. Such Networks may be established within a building. Computers that are part of Local-Area Networks are Personal Computers ( PCs ) or microcomputers. These Computers are connected to each other. Simple communication lines connect these Pers Networks bring people together. When people join  hands teamwork becomes possible. The structural composition of LANs simplifies teamwork. In other words, LAN hardware supports teams having similar processing requirements. LAN Computers readily support personalization of tasks allocated to professionals.  Office staff can work together and share information. This improves the efficiency of the entire workforce. It has been noted that here all the Networked Computers are Personal Computers. They are of equal capacity. Mostly LAN users have similar tasks. If situations allow, a user is independent to access any Computer to serve his purpose. LAN users can exercise the option of secu...

A Point-to-point Network is a communication Network. Existence of several points is recorded in a Point-to-point Network. These points are important locations and are called nodes. Here information is passed from previous point to  next point. We mean from node to node.  Let us suppose that information is at the first point ( node ) of a Point-to-point Network. The information at the first point has a size. It has to go from first point to second point. To go from the first point to the second, a communication line is needed. This communication line should be free enough to carry the size of information at the first point.  Now, one more requirement exists. The second point of a Point-to-point Network is the point to receive information from the first point. This        point should have enough memory space. This space should be enough to fit the size of information at the first point.  If a node in a Point-to-point Network has large storage capac...

Network Architecture has two aspects:  A ) Design: The design is drawn in detail. The detailed plan is carefully prepared. B ) Implementation: The implementation is properly effected. The Network is given a concrete shape. In the study of Network Architecture the theoretical approach is useful for Network Design related issues. The practical approach to Network Architecture focuses on actual Networking activities. The practical aspects of the concrete Network implementation is very interesting. Network Architecture is not the same for all the Networks. Factors that affect Network Architecture are: 1 ) Nodal Configuration: Configuration of Computers used as nodes of the Network greatly affects Network Architecture. All the nodes may be having the same configuration. In this case the nodes are actually peers. If out of two nodes, one is  having a high configuration and another one is having minimal configuration, then a different case results.   2 ) Network Service: Network...

Networks are designed to serve. They are used for practical purposes in the following fields: Healthcare: Hospitals, Nursing Homes, Pathological Laboratories use Computer Networks to meet health requirements of the people. The healthcare professionals and assistants closely cooperate for a healthy society. The professionals and assistants come together using Networks. It can be said that Networks keep the healthcare units in functional state. Educational Institutions: These institutions use Networks for many purposes. Student admissions, teaching work, laboratory work, and project report generation are possible using Networks. Teachers refer to online tutorials and their valued classroom  sessions are admired by the student community.   Government Agencies: Government programmes work at different levels. The lower level activities are reported to high ranking officers. These reports are carefully studied. After making the study at the officers' level fresh instructions are gi...