1. 3/11/20211 IT 202: Web Technology (WT) Pramit Mazumdar

2. Topics 4-layered OSI (TCP/IP model) Protocols in Application layer Web applications Benefits of web applications Client-server architecture Thin and Thick clients 2

3. Web Protocols Internet protocol suite  Also known as the TCP/IP protocol  The TCP and IP driven design encapsulates the functions of the 7 classic OSI layers in only 4 layers 3

4. Web Protocols (cont’d) Internet protocol suite  Application layer (ex: HTTP): Contains protocols for all protocol- specific data communication services at a process-to-process level  Transport layer (TCP): Handles host-to-host communication  Network/Internet layer (IP): Connects local networks, establishing internetworking  Data Link layer (Ethernet): Communicates for the local network 4

5. Web Protocols (cont’d) 5 Two Internet hosts connected via two routers and the corresponding layers used at each hop

6. Web Protocols (cont’d) 6 Example of protocols at various layers

7. Web Protocols (cont’d) Other web/application protocols,  FTP  SFTP  SSH  SMTP  HTTP  HTTPS  SSL  Telnet 7

8. Web Protocols (cont’d) Other web/application protocols  FTP: File transfer protocol – protocol for file transfer across systems  SFTP: Secure FTP – protocol to run FTP securely  SSH: Secure shell protocol – establishes a secure peer-to-peer connection across computers  SMTP: Simple mail transfer protocol – protocol for email exchange 8

9. Web Protocols (cont’d) Other web/application protocols  HTTP: Hypertext transfer protocol – application protocol for web site and web service level data exchange  HTTPS: Secure HTTP – protocol to run HTTP securely  SSL: Secure socket layer – establishes a secure socket connection across computers  Telnet: Telephone network protocol – used in early days of networking to connect across computers 9

10. Web Applications Applications that run on the web Structures using three primary tiers  Front tier  Middle tier  Back end database tier Can be interactive 10

11. Web Applications Front tier:  considers design and presentation aspects to users. Middle tier:  contains business intelligence and carries out the requisite processing. Back end database tier:  it is responsible for storing and managing data. 11

12. Web Applications (cont’d) Benefits  Browser-based  No complex deployment process at client end  Application is expected to work as long as  the client has a web browser  can connect to application portal  Require little to no disk space on client machine 12

13. 3/11/202113 Thank You