Chapter 2 - Application Layer

Question 1

Application Architecture

Answer 1

the way in which the functions of the application layer software are spread among the clients and servers in the network.

Question 2

What are the five general functions of an application program?

Answer 2

Data storage, data access logic, application logic, presentation logic, and services logic.

Question 3

Host-based architecture

Answer 3

An application architecture in which the server (or host computer) performs most of the work.

Question 4

Client-based architecture

Answer 4

An application architecture in which the work is shared between teh servers and clients.

Question 5

Cloud-based architecture

Answer 5

An application architecture in which the cloud provides services (software, platform, and/or infrastructure) to the client.

Question 6

Thin-client architecture

Answer 6

Places little or no application logic on the client

Question 7

Thick-client architecture

Answer 7

Places all or almost all of the application logic on the client.

Question 8

Server farm

Answer 8

A cluster of computers linked together so that they act as one computer.

Question 9

Software as a Service (SaaS)

Answer 9

A cloud computing model in which an organization outsources the entire application to the cloud provider and uses it as any other application that is available via the browser (thin client).

Question 10

Multitenancy

Answer 10

rather than having many copies of the same application, there is only one application that everybody shares, yet everybody can customize it for his or her specific needs.

Question 11

Platform as a Service (PaaS)

Answer 11

The organization manages the application and its own data but uses the database software (data access logic) and operating system provided by the cloud provider.

Question 12

Peer-to-Peer (P2P) Architectures

Answer 12

All computers act as both a client and a server. Therefore, all computers perform all four functions: presentation logic, application logic, data access logic, and data storage

Question 13

Infrastructure as a Service (IaaS)

Answer 13

The cloud provider manages the hardware, including servers, storage, and networking components. The organization is responsible for all the software, including operating system (and virtualization software), database software, and its applications and data.

Question 14

Why are almost all new applications today client-server?

Answer 14

They provide the best scalability, or the ability to increase/decrease server capacity; they are the most reliably; they are the cheeapest.

Question 15

What is the standard protocol for communication between a Web browser and a Web server?

Answer 15

Hypertext Transfer Protocol (HTTP)

Question 16

What are the three parts of an HTTP request from a Web browser to a Web server?

Answer 16

1) The request line, which stards with a command, provides the Web page, and ends with the HTTP version number that the browser understands.

2) The request header, which contains a variety of optional information

3) The request body, which contains information sent to the server

Question 17

What are teh three parts of an HTTP resposne from the server to the browser?

Answer 17

1) The response status, which contains the HTTP version number the server has used, a status code, and a reason phrase

2) The response header, which contains a variety of optional information, such as the Web server being used, the date, and the exacft URL of the page in the response

3) The response body, which is the Web page itself.

Question 18

What is the most commonly used emails tandard?

Answer 18

Simple Mail Transfer Protocol (SMTP)

Question 19

What are the two parts of an SMTP packet?

Answer 19

1) The header, which lists source and destination email addresses as well as the address itself, date, subject, etc.

2) The body, which is the word DATA, followed by the message itself.