JITHA'S CL-CY LEVEL 1 REPORT

29 / 3 / 2025

TASK 7: OSI

Objectives:

1. Research and create a simple visual representation or diagram of the OSI model using a cloud-based diagramming tool like Draw.io.
2. Learn about the OSI architecture along with the protocols, switching, routing, handshakes, and IP addressing.
3. Write a brief explanation of each layer of the OSI model and how it relates to cloud computing!

Learnings:

OSI (Open Systems Interconnection) model describes seven layers that computer systems use to communicate over a network. It was designed by ISO in 1984.

1. Application layer provides services for network applications with the help of protocols to perform user activities like for file transfer FTP(File Transfer Protocol), for web surfing HTTP(S)(Hypertext Transfer Protocol(Secure)), for emails SMTP(Simple Mail Transfer Protocol) etc.
2. Presentation layer receives data(which will be in the form of characters and numbers) from application layer, then reduces it into computer understandable binary form (Translation), further reduces the bits(Data compression), encrypts the data at the sender’s end(Encryption) and decrypts it at the receiver’s end(Decryption).
3. Session layer helps in authentication, authorisation and session management with the help of APIs like NETBIOS(Network Basic Input Output System).
4. Transport layer controls the reliability of communication through segmentation, flow control and error control(by checksum) and performs both connection oriented as well as connectionless transmission of data via TCP(Transmission Control Protocol) and UDP(User Datagram Protocol)
5. Network Layer receives data segments from Transport layer. These data segments will now be called packets. Functions of this layer include : logical addressing(IP addressing), routing(moving of data from source to destination based on logical addressing and mask) and path determination(choosing best possible path for data delivery, using protocols like OSPF(Open Shortest Path First), BGP(Border Gateway Protocol), IS-IS(Intermediate System to Intermediate System) etc.)
6. Data Link Layer receives data packets from network layer and further adds header and tailer to form frame. With CSMA(Carrier-sense multiple access) method, it controls data transmission by preventing collisions and managing access to communication media shared by devices on a network. Tail of the frame generally contains bits which are used to detect errors in the received data.
7. Physical layer transmits the binary data(0s and 1s) in the form of signals between devices through cables or wireless media like LAN cable, optical fibre, air etc.

TASK 8: IaaS, PaaS and SaaS

Objective:

Learn about the types of cloud computing service models and write a brief explanation of each.

Learnings:

Cloud computing refers to the delivery of computing services over the internet

Types of Cloud Computing service models:

Infrastructure as a Service (IaaS)

• Provides virtualized computing resources like servers, storage, and networking
• Users have control over operating systems, applications, and storage.
• Examples: Amazon Web Services (AWS) EC2, Google Compute Engine, Microsoft Azure.

Advantages:

• Scalability: Easily scale up/down based on demand.
• Cost-Effective: Pay only for what you use.
• Full Control: You manage OS, storage, deployed apps, etc.
• No Hardware Maintenance: Infrastructure is managed by the provider.

Disadvantages:

• Management Complexity: Requires skilled personnel to manage and configure.
• Security: You're responsible for securing your own apps and data.
• Vendor Lock-in: Switching providers may be difficult.

Applications:

• Hosting websites or applications
• Storage, backup, and recovery
• High-performance computing (HPC)
• Development and testing environments

Platform as a Service (PaaS)

• Delivers a platform that allows developers to build, test, and deploy applications without managing the underlying infrastructure.
• Examples: Google App Engine, Microsoft Azure App Service, Heroku.

Advantages:

• Speed: Quick development and deployment of apps.
• No OS Maintenance: Provider manages OS, runtime, and middleware.
• Built-in Tools: Database, DevOps, analytics, etc., are included.

Disadvantages:

• Limited Control: Less control over underlying infrastructure.
• Vendor Lock-in: Custom features may not be portable.
• Runtime Restrictions: Limited to languages and frameworks supported by the provider.

Applications:

• Application development frameworks
• Business analytics and intelligence
• API development and management

Software as a Service (SaaS)

• Offers software applications over the internet on a subscription basis.
• Examples: Microsoft 365, Salesforce, Google Workspace.

Advantages:

• No Installation Needed: Access via browser or app.
• Automatic Updates: Always up-to-date.
• Accessibility: Accessible from anywhere with internet.

Disadvantages:

• Limited Customization: Can't tweak core functionality.
• Data Security: Sensitive data stored offsite.
• Dependency: You're at the mercy of the provider’s uptime and policies.

Applications:

• Email, collaboration tools, CRM
• Document management
• Accounting and billing systems