Sunday, 25 May 2014
Friday, 16 May 2014
Tutorial 2
Open Systems Interconnection (OSI) is a standard description for transmitting messages between any two points in a telecommunication network. The purpose of the OSI is to guide product implementors and ensure the product will work consistently with other products. OSI consist of seven layer that were The application layer, The presentation layer, The session layer, The transport layer, The network layer, the data-link layer and lastly The physical layer. Each layer having difference special and related functions. These layers are separated into two group. the upper four layer are used whenever a message passes from or to a user. The lower three layers are used whenever the message passes through the host computer. The seven layers are:
Layer 7: The application layer
This layer is which the comunication partners are identified, quality of service is identified, user authentication and privacy is considered and any constraints on data syntax are identified.
Layer 6: The presentation layer
This layer is part of an operating system that converting outgoing and incoming data from one presentation format to another. This layer are also name as syntax layer.
Layer 5: The session layer
This layer sets up, coordinates, and terminates conversations, exchanges, and dialogs between the application at each end. It deals with session and connection coordination.
Layer 4: The transport layer
This layer will ensure the complete data transfer. It manage the end to end control and error checking.
Layer 3: The network layer
This layer handles the routing and forwarding of data. It make sure the data is send to the right destination on the outgoing transmission and incoming transmission at the packet level.
Layer 2: The data-link layer
This layer provides synchronization for the physical level and does bit-stuffing for strings of 1's in the excess of 5. It furnishes transmission protocol knowledge and management.
Layer 1: The physical layer
This layer conveys the bit stream through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier.
Server-side code and Client-side code
In web applications contain the client and server. The client is like the web browser. The server is a web application server at a remote location that will process web requests and send pages to the client. There are several server-site technologies that can be used when developing web applications. Server-side processing is used to interact with permanent storage like databases or files. The server will render pages is first requested and when pages are posted back to the server. Server-side code required a long time to process unlike the Client-side code. Client-side code also having more interactive application and less overhead on the web server. Client side code is ideal for when the element of the page to be changed without contact the database. Client-side code form a validation alerts but Server-side code validating data prior to saving. moreover, Client-side code calculations based on page values but Server-side code filtering data by permissions. In Client-site code the layout positioning can be change but in server-site code must be deleting data or remove. Client-site code set values to input areas and server-site code working with sensitive data.
Application server and web services
Web services are services with standard interfaces that just expose a behavior. Web applications are full blown browser-based applications that also include an interface. Web services are granular. Web application are complete holistic functions that are bound into a single application. A web application is an application that is accessed through a web browser running on client's machine whereas a web service is a system of software that allow different machines to interact with each other through a network. Web server do not necessarily have a user interface, while a web application is a complte application with a GUI. Web services can be used to communicate or transfer data between web application running on different platforms.
The web application example is Google Documents, Meebo and Slide Rocket.
The Web Services example is Web service mocking, Web service inspection and Web service load test.
Layer 7: The application layer
This layer is which the comunication partners are identified, quality of service is identified, user authentication and privacy is considered and any constraints on data syntax are identified.
Layer 6: The presentation layer
This layer is part of an operating system that converting outgoing and incoming data from one presentation format to another. This layer are also name as syntax layer.
Layer 5: The session layer
This layer sets up, coordinates, and terminates conversations, exchanges, and dialogs between the application at each end. It deals with session and connection coordination.
Layer 4: The transport layer
This layer will ensure the complete data transfer. It manage the end to end control and error checking.
Layer 3: The network layer
This layer handles the routing and forwarding of data. It make sure the data is send to the right destination on the outgoing transmission and incoming transmission at the packet level.
Layer 2: The data-link layer
This layer provides synchronization for the physical level and does bit-stuffing for strings of 1's in the excess of 5. It furnishes transmission protocol knowledge and management.
Layer 1: The physical layer
This layer conveys the bit stream through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier.
Server-side code and Client-side code
In web applications contain the client and server. The client is like the web browser. The server is a web application server at a remote location that will process web requests and send pages to the client. There are several server-site technologies that can be used when developing web applications. Server-side processing is used to interact with permanent storage like databases or files. The server will render pages is first requested and when pages are posted back to the server. Server-side code required a long time to process unlike the Client-side code. Client-side code also having more interactive application and less overhead on the web server. Client side code is ideal for when the element of the page to be changed without contact the database. Client-side code form a validation alerts but Server-side code validating data prior to saving. moreover, Client-side code calculations based on page values but Server-side code filtering data by permissions. In Client-site code the layout positioning can be change but in server-site code must be deleting data or remove. Client-site code set values to input areas and server-site code working with sensitive data.
Application server and web services
Web services are services with standard interfaces that just expose a behavior. Web applications are full blown browser-based applications that also include an interface. Web services are granular. Web application are complete holistic functions that are bound into a single application. A web application is an application that is accessed through a web browser running on client's machine whereas a web service is a system of software that allow different machines to interact with each other through a network. Web server do not necessarily have a user interface, while a web application is a complte application with a GUI. Web services can be used to communicate or transfer data between web application running on different platforms.
The web application example is Google Documents, Meebo and Slide Rocket.
The Web Services example is Web service mocking, Web service inspection and Web service load test.
Thursday, 15 May 2014
Static vs Dynamic Websites
There is two type of website we are using: Static and Dynamic Websites. There are many static websites on the internet we use but we won't be easily know that is it the website is static website or not. Static website can only be updated by someone with high knowledge about website development. There are many small company using static website because static website is easy and fast to develop. Static website is also cheap to develop or host. Static Websites having advantage as well as disadvantage. Static websites require the user to having a high knowledge about creating a websites and also require a web expertise to update the site. The site is not so useful to the user compare to dynamic websites. Static website is also very stagnant compare to the dynamic websites. In the other hand, The dynamic websites is a much more functional websites and easier to update the content or data compare to static websites. Dynamic websites can also work as a system to allow staff or users to collaborate. If there are new content or added information, the websites will bring people back to the site and helps in the search engines. The disadvantage for dynamic website is it will much slower compare to static websites and it is very costly to develop and hosting. There are many static websites from the last decade but now there are more and more people or user realise the advantages of dynamic websites that is more useful for user so the websites now is mostly a dynamic websites.
Static website
Dynamic websites
Friday, 9 May 2014
Tutorial 1
Hypertext Transfer Protocol (Http)
Hypertext Transfer Protocol Secure (Https)
When we are request of some information through the browser, there are two type of transfer. The packet-switched Network is a more commonly use for data. The address information send from web server will break into many small packets and each packets will contain of the address information that the client request . When using Packet-Switched Network, the client's HTTP request will break down to small piece and transfer to ISP or Name server then transfer again to the Web server. The request will regroup and form a correct request and the web server will will send the HTML document back to ISP or name server. The HTML document will break down into small piece and send back to the client browser and recompiled back into the original data and message in correct sequence. Then the HTML document or any website will shown correctly.
Different between Cellular transmission 3G and 4G
3G is a digital broadband service that uses packet data transmission. this makes us to surf the Web and get the email on our cell phone quickly and easily. The 4G technology will actually 10 times faster than 3G. The Cellular transmission speeds have a lot of variables like the underlying technology, the carrier, the location of the cell tower,and the amount of congestion on the network. The 4G technology speed now is almost similar as DSL connection. The voice and data will be transmitted separately with 3G but transmitted together with 4G so 4G will be much faster response time.The 3G cellular transmission will become very slow after the usage of the client finish compare to 4G. The limitation of 3G is requires close base stations and very expensive. However, the limitation of 4G is the operation area.
Hypertext Transfer Protocol means for the underlying protocol used by the World Wide Web. HTTP actually stand for how messages or information are formatted and transmitted from the browser to the Web servers in response to various commands. When we enter a HTTP command on a browser, it is actually
sending a command to the Web server to directly send or transmit the Web page that we request. We can also call HTTP as stateless protocol because each command is executed independently.
Hypertext Transfer Protocol Secure (Https)
Hypertext Transfer Protocol Secure short form as (Https) is almost same as the Hypertext Transfer Protocol but it was secure by a socket layer call (SSL) for security purpose. Hypertext Transfer Protocol Secure is normally use for online banking or any investment website so that the client privacy will be protected. If someone was trying to capture others people credit card number or any private information via HTTPS that he or she enter before, the data would send back to the SSL encryption and it would be unrecognizable. We can know that the website is using Hypertext Transfer Protocol Secure when the web address start with https://.
Packet-Switched Network
Different between Cellular transmission 3G and 4G
3G is a digital broadband service that uses packet data transmission. this makes us to surf the Web and get the email on our cell phone quickly and easily. The 4G technology will actually 10 times faster than 3G. The Cellular transmission speeds have a lot of variables like the underlying technology, the carrier, the location of the cell tower,and the amount of congestion on the network. The 4G technology speed now is almost similar as DSL connection. The voice and data will be transmitted separately with 3G but transmitted together with 4G so 4G will be much faster response time.The 3G cellular transmission will become very slow after the usage of the client finish compare to 4G. The limitation of 3G is requires close base stations and very expensive. However, the limitation of 4G is the operation area.
Activity 1
Hypertext is text displayed on a computer with references to other text that the reader can immediately access.Moreover, Hypermedia is a computer-based information retrieval system that enables a user to gain or provide access to audio and video recording, photograph and graphics related to a particular system. TCP or IP establishes the connection to the web server. As i mention, Hypertext Transfer Protocol enables the web server software and the client software to communicate though all browser. HTTP communication consist of 2 phases, the request phase and the response phase. There are two parts in HTTP communication between all the type of browser and the web server. It was the header and the body.
HTTP Request having 4 general form that was HTTP method Domain part of the URL HTTP ver. , Header fields, blank line, Message body. The common methods is shown below:
HTTP Request Phase
HTTP Request having 4 general form that was HTTP method Domain part of the URL HTTP ver. , Header fields, blank line, Message body. The common methods is shown below:
GET
|
Fetch a document
|
POST
|
Execute the document using the data in the body
|
HEAD
|
Fetch just the header of the document
|
PUT
|
Store a new document on the server
|
DELETE
|
Remove a document from the server
|
The client using any type of browser and type in any website of domain name and the HTTP Request will summit the data to the ISP or Name Server and translate the domain name to IP address and the HTTP Request will send again to the web server like Apache, IIS, Unix, Linux and NT. After responded from the web server, the web server will send the HTML document along with the HTTP Respond to the ISP or Name Server. after the TSP or Name Server get the HTTP Respond and HTML document, ISP or the Name Server will sent the Respond along with the document to the browser which the client asked.
HTTP Response Phase
Server Response is in the form of status line like (HTTP /1.1 200 OK). The status contain response header fields, Blank line and the Response body. The status code contain of 3 digit of number and the first digit specifies the general status. There are 5 Sever Response as shown below:
First Digit
|
Category
|
1
|
Informational
|
2
|
Success
|
3
|
Redirection
|
4
|
Client Error
|
5
|
Server Error
|
The client request with any type of browser will send to the ISP or Name Server with translating the Domain Name to the IP address. The ISP or Name Server will send the IP address that they change to the Web Server and Get the HTML document from the Web Server. After the Web Server get the HTML document, they will sent the document along with the HTTP Respond back to the ISP or Name Server and the ISP or Name Server send the document that the client request to their browser. The client will normally get the Response of 200 means that they get their HTML document as they requested. If the browser show 300 means that further action need to be taken to complete the request. If the client does not get the document as they want, the browser that the client use will show with 400 (Client Error) or 500 (Server Error). the Response of 400 means the client type a wrong domain name. If the browser show the Response of 500 means the server cant complete the task and it may be cause by the server is temporarily down.
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