ITEC 4020 - L2: Internet Protocols

Latency

The time it takes for data to travel from the source computer to the destination.

Bandwidth

The rate at which data can be transmitted, measured in bits per second.

Message Transmission Time

The sum of latency and data size divided by transfer rate.

OSI Model

Seven-layer network model including Application, Presentation, Session, Transport, Network, Data Link, and Physical.

Application Layer (OSI)

Defines communication requirements for specific applications such as HTTP, FTP, and SMTP.

Presentation Layer (OSI)

Handles data representation and encryption to ensure independence across systems.

Session Layer (OSI)

Manages connections, reliability, and recovery between applications.

Transport Layer (OSI)

Provides end-to-end reliability using TCP or UDP.

Network Layer (OSI)

Handles routing and addressing of packets using IP.

Data Link Layer (OSI)

Manages direct transmission between nodes on the same link, using protocols like Ethernet or PPP.

Physical Layer (OSI)

Transmits raw bits using electrical, optical, or radio signals.

TCP/IP Stack

Simplified four-layer model consisting of Application, Transport, Internet, and Network Interface.

TCP (Transmission Control Protocol)

Reliable, connection-oriented transport protocol that retransmits lost packets.

UDP (User Datagram Protocol)

Unreliable, connectionless transport protocol where packets may follow different routes.

IP (Internet Protocol)

Adds source and destination addresses to packets and handles routing.

HTTP (HyperText Transfer Protocol)

Client-server protocol where clients send requests and servers return responses, typically over port 80.

HTTP 1.0

Connectionless protocol where the server closes the connection after each request.

HTTP 1.1

Connection-oriented protocol where the server keeps the connection open for multiple requests.

HTTP Methods

Includes GET, HEAD, POST, PUT, DELETE, TRACE, and OPTIONS.

GET (HTTP Method)

Requests a resource whose URL follows.

HEAD (HTTP Method)

Similar to GET but returns only headers such as size and type.

POST (HTTP Method)

Sends user data to the server, commonly used with forms.

PUT (HTTP Method)

Stores or updates data at a specific resource location.

DELETE (HTTP Method)

Removes the resource specified by the URL.

TRACE (HTTP Method)

Echoes the request for diagnostic purposes.

OPTIONS (HTTP Method)

Returns the HTTP methods supported by the server.

Servlet

A Java class that handles HTTP requests and responses, typically via doGet() and doPost() methods.

doGet()

Servlet method that handles HTTP GET requests.

doPost()

Servlet method that handles HTTP POST requests.

HttpServletRequest

Java object containing client request data, such as parameters and sessions.

HttpServletResponse

Java object for sending data back to the client, such as setting content type or writing output.

Session Tracking

Technique to maintain user state across requests using cookies or HttpSession objects.

HttpSession

Java class for maintaining client-specific session data.

Java Server Pages (JSP)

Technology combining HTML with Java code, compiled into servlets for dynamic web content.

JSP Directives

Define page settings, compilation instructions, and custom libraries.

JSP Actions

Predefined tags that encapsulate functionality, such as jsp:include.

JSP Scriptlets

Java code embedded within JSP using

JSP Tag Libraries

Reusable custom tag extensions used in JSP pages.

JSP Scopes

Application, Page, Request, and Session object lifetimes within JSP execution.

MVC Architecture

Software design pattern dividing application into Model (data/logic), View (UI), and Controller (request handling).

Servlet as Controller

Servlets manage user input and forward results to views in MVC architecture.

JSP as View

JSP pages provide presentation and user interface in MVC architecture.

JavaBeans as Model

Reusable Java components that store data and business logic in MVC applications.