Notes for BSc CSIT

Network topology Network topology refers to how the nodes and links in a network are arranged. A network node is a device that can send, receive, store, or forward data. A network link connects nodes and may be either cabled or wireless links. Understanding topology types provides the basis for building a successful network. There are a number of topologies but the most common are bus, ring, star, and mesh: A bus network topology is when every network node is directly connected to a main cable. In a ring topology, nodes are connected in a loop, so each device has exactly two neighbors. Adjacent pairs are connected directly; non-adjacent pairs are connected indirectly through multiple nodes. In a star network topology, all nodes are connected to a single, central hub and each node is indirectly connected through that hub.  A mesh topology is defined by overlapping connections between nodes. You can create a full mesh topology, where every node in the network is connected to every ot...

 Disaster recovery (DR)   Disaster recovery (DR) is an area of security planning that aims to protect an organization from the effects of significant negative events. DR allows an organization to maintain or quickly resume mission-critical functions following a disaster. A disaster can be anything that puts an organization's operations at risk, from a cyberattack to equipment failures to natural disasters. The goal with DR is for a business to continue operating as close to normal as possible. The disaster recovery process includes planning and testing and may involve a separate physical site for restoring operations. The recovery point objective (RPO) differs from the recovery time objective (RTO):- Recovery point objective (RPO) and recovery time objective (RTO) are two important measurements in disaster recovery and downtime. RPO is the maximum age of files that an organization must recover from backup storage for normal operations to resume after a disaster. The recov...

 Virtualization is one of the key components of the cloud computing paradigm, especially in infrastructure as a service model where the mentioned technology is essential to provide a large set of computing resources. Some experts even define cloud computing as simple as virtualized hardware and software plus advanced monitoring and resource management technologies. To say it straight and clear, without virtualization, cloud computing would leave the data unstable, uncontrolled, and unsafe. It is an important and probably an inseparable element of cloud computing services. Virtualization allows us to consolidate multiple physical components so that they can be managed in one place. With the help of virtualization, organizations have better visibility and also greater control of their infrastructure making security management simpler for the cloud. It is due to virtualization that cloud computing services are so cost-effective. Moreover, it is also responsible for the simplicity of d...

 A service-oriented architecture is essentially a collection of services. These services communicate with each other. The communication can involve either simple data passing or it could involve two or more services coordinating some activity. The reality in IT enterprises is that infrastructure is heterogeneous across operating systems, applications, system software, and application infrastructure. Some existing applications are used to run current business processes, so starting from scratch to build new infrastructure isn't an option. Enterprises should quickly respond to business changes with agility; leverage existing investments in applications and application infrastructure to address newer business requirements; support new channels of interactions with customers, partners, and suppliers; and feature an architecture that supports organic business. SOA with its loosely coupled nature allows enterprises to plug in new services or upgrade existing services in a granular fashio...

 Elastic IP address An Elastic IP address is a static IPv4 address designed for dynamic cloud computing. An Elastic IP address is associated with your AWS account. With an Elastic IP address, you can mask the failure of an instance or software by rapidly remapping the address to another instance in your account.  An Elastic IP address is a public IPv4 address, which is reachable from the Internet. If your instance does not have a public IPv4 address, you can associate an Elastic IP address with your instance to enable communication with the Internet; for example, to connect to your instance from your local computer.  Elastic IP addresses are used by AWS to manage its dynamic cloud computing services. Within the AWS infrastructure, customers have virtual private clouds (VPCs). Within the VPCs, users have instances. The Elastic IP address is what is used to advertise the data within the instance to the public internet. Works: Each EIP can be assigned to one instance, in whi...

  Service-oriented architecture (SOA)  Service-oriented architecture (SOA) references a set of principles and methodologies applied by software engineers to design and develop software in the form of interoperable services. Services are usually built in the form of components that can be reused for different purposes than originally intended. For this reason, the interfaces are often defined in a practical manner, allowing use across varying applications and multiple platforms. The principal characteristics of SOA are described in more detail here: SOA is black-box component architecture. The black box lets you reuse existing business applications; it simply adds a fairly simple adapter to them. You don’t need to know every detail of what’s inside each component; SOA hides the complexity whenever possible. SOA components are loosely coupled. Software components are loosely coupled if they’re designed to interact in a standardized way that minimizes dependencies. One loosely co...

 Service-oriented architecture (SOA)  Service-oriented architecture (SOA) references a set of principles and methodologies applied by software engineers to design and develop software in the form of interoperable services. Services are usually built in the form of components that can be reused for different purposes than originally intended. For this reason, the interfaces are often defined in a practical manner, allowing use across varying applications and multiple platforms. We can characterize SOA as follows: • In SOA, Services should be independent of other services. Altering a service should not affect the calling service. • Services should be self-contained. When we talk about Register Customer service it means, the service will do all the necessary work for us, we are not required to care about anything. • Services should be able to define themselves. Services should be able to answer the question of what it does? It should be able to tell the client what all operations...

  Jericho cloud cube model  Jericho Forum is an international independent group of information security leaders & their focus is on how to protect and secure cloud networks. They put forward a model that helps to categorize a cloud network based on four-dimensional factors. The Jericho Cloud Cube Model describes the multidimensional elements of cloud computing, framing not only cloud use cases, but also how they are deployed and used. The Cloud Cube Model, established and developed by the Jericho Forum, assists in categorizing cloud networks based on four dimensions: Internal/External Proprietary/Open Perimeterised/De-perimeterized  Insourced/Outsourced Four-Dimensional model: 1. Physical Location of Data: Data can be stored inside or outside, which ultimately establishes the organization's boundaries. 2. Ownership: Ownership can be proprietary or open; it not just measures the ownership of technology but also its interoperability, data use, and ease of data transfer,...

   The relationship between SOA and cloud architecture, To begin, it is crucial to highlight that Service-Oriented Architecture may be used with or without cloud computing. As more firms move file storage to the cloud, it makes sense to employ cloud computing and Service-Oriented Architecture together. Cloud computing enables users to quickly and easily develop services suited to their clients without needing to consult an IT staff. One disadvantage of combining SOA and Cloud is that some factors, such as security and availability, are not assessed. The integration of current data and systems into the cloud solution is a significant problem for enterprises when combining cloud computing and Service-Oriented Architecture. For the transition to be seamless, there must be continuity from beginning to end. It is also crucial to remember that not every IT function can be outsourced to the cloud. CLOUD DESIGN AND IMPLEMENTATION USING SOA Elasticity, self-service provisioning, standa...

 Thread is different from the task in the following ways:- A t ask  describes a program that may need input files and generate output files as a result of its execution and applications are a collection of tasks. Tasks are submitted for execution, and their Output data is gathered at the conclusion. The way tasks are produced, the sequence in which they are executed, and whether they need data interchange to distinguish the application models that come under the task programming umbrella.  A Task may be used to indicate what you want to perform, and then that Task may be attached to a Thread. Threads are utilized to finish the task by splitting it up into pieces and executing them individually in a distributed system. A  thread  is a fundamental unit of CPU utilization that consists of a program counter, a stack, and a collection of registers. Threads have their program and memory areas. A thread of execution is the shortest series of programmed instructions tha...

 Cloud Computing   Cloud Computing is the delivery of on-demand IT resources (such as the Internet, database, Server, Big-Data, etc ) implemented on the internet to process, manage and store data. In cloud computing, we can pay for only those resources which we have used. Benefits of Cloud Computing: Data backup and Storage of data Powerful  server capabilities Incremental  Productivity Cost-effective and Time-saving Agility (Access to a broad range of technology) Elasticity  The differentiating public cloud from the private cloud. Public Cloud :  The cloud services which are exposed to the public and can be used by anyone are called public clouds. The public cloud is owned, managed, and operated by businesses, universities, and government organizations. In the public cloud, data centers are located anywhere on the internet.  P rivate Cloud:  The cloud services which are private in the internal network within the organizations and selected users i...

  BUSINESS AND CONSUMER APPLICATIONS  Cloud computing innovations are likely to help the commercial and consumer sectors the most. On the one hand, the ability to convert capital expenses into operating costs makes clouds an appealing alternative for any IT-centric business. On the other hand, the cloud's feeling of ubiquity in terms of accessing data and services makes it appealing to end-users. Furthermore, because cloud technologies are elastic, they do not necessitate large upfront investments, allowing innovative ideas to be easily converted into products and services that can readily scale with demand.

 Architecture of Cloud computing Cloud computing is utility-oriented and Internet Centric way of delivering IT services on demand. cloud computing architecture includes  i) infrastructure as a service i)platform as service  iii) software as a service From the figure above, we will discuss i) infrastructure as a service ii)platform as service iii) software as a service  iv) user-level middleware v) User application  vi) core middleware vii) system infrastructure. 1. IAAS It provides access to fundamental resources such as physical machines, virtual machines, virtual storage, etc. Characteristics: virtual machines with pre-install s/w virtual machines with preinstall os  on-demand availability of resources Allow copying of the particular data at different locations. resources can be easily scaled up and down. 2. PAAS :  platform as a service offers the runtime environment for the application. It offers development and deployment tools Required to develop...

  BIOLOGY: PROTEIN STRUCTURE PREDICTION (PSP) Cloud computing is a new technology that allows users to access a variety of computer services on demand. It gives users easy access to a pool of higher-level services and other system resources. Cloud computing has become more important in the realms of geology, biology, and other scientific studies. The finest example of a study area that uses cloud technologies for processing and storage is protein structure prediction. A protein is made up of peptide bonds that connect lengthy sequences of amino acids. The varied structures of proteins aid in the development of novel therapeutics, and Protein structure prediction is the prediction of various sequences of proteins based on their three-dimensional structure. Protein primary structures are created first, and secondary, tertiary, and quaternary structures are predicted from the fundamental structure. Protein structural predictions are made in this manner. Protein structure prediction em...

  Applications that can benefit from cloud computing 1) Scientific Applications Scientific applications have been run on both traditional high-performance computing (HPC) systems such as supercomputers and clusters, as well as high throughput computing (HTC) platforms such as Grids, for many years. Many businesses have employed classical HPC to assist tackle a range of problems since they have access to enormous quantities of computer power. Although these systems were often built to solve a specific problem, a growing number of SMEs and even university departments began to use general-purpose HPC systems. Scientists, engineers, system administrators, and developers have been investigating HPC Cloud environments to take advantage of what Cloud Computing has to offer them as new growing technology. Running complex scientific applications has become more accessible to the research community thanks to the popularity of Cloud Computing, which allows researchers to access on-demand comp...