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Q6-3 How Does the Cloud Work?

WSDL/SOAP Web Service Protocols 257
http, https,
Application layer smtp, ftp
protocols
Internet Protocols
(TCP/IP Protocol
Internet ‘plumbing’ 4 more layers Architecture)
protocols of protocols
Figure 6-14
Protocols That Support Web
Services

Internet Protocols: http, https, smtp, and ftp
The only Internet protocols that you as a business professional are likely to encounter are those
at the top, or the application layer of the TCP/IP architecture, shown in Figure 6-14. Hypertext
Transfer Protocol (http) is the protocol used between browsers and Web servers. When you use
a browser such as Microsoft Edge, Safari, or Chrome, you are using a program that implements the
http protocol. At the other end, at the New Zealand hotel mentioned earlier, for example, there is
a server that also processes http. Even though your browser and the server at the hotel have never
“met” before, they can communicate with one another because they both follow the rules of http.
Similarly, in Figure 6-13, the browsers send and receive service requests to and from the commerce
server using http.
As you will learn in Chapter 10, there is a secure version of http called https. Whenever you
see https in your browser’s address bar, you have a secure transmission and you can safely send
sensitive data like credit card numbers. When you are on the Internet, if you do not see https, then
you should assume that all of your communication is open and could be published on the front
page of your campus newspaper tomorrow morning. Hence, when you are using http, email, text
messaging, chat, videoconferencing, or anything other than https, know that whatever you are
typing or saying could be known by anyone else.
Two additional TCP/IP application-layer protocols are common. smtp, or Simple Mail
Transfer Protocol, is used for email transmissions (along with other protocols). ftp, or File
Transfer Protocol, is used to move files over the Internet. Google Drive and Microsoft OneDrive
use ftp behind the scenes to transmit files to and from their cloud servers to your computer.

WSDL, SOAP, XML, and JSON

To wrap up the discussion, we will briefly consider four standards used extensively for Web
services and the cloud. Those standards and their purpose are as follows:

WSDL (Web Services A standard for describing the services, inputs and outputs, and
Description other data supported by a Web service. Documents coded
Language) according to this standard are machine readable and can be used
by developer tools for creating programs to access the service.
SOAP A protocol for requesting Web services and for sending
(no longer an acronym) responses to Web service requests.

XML A markup language used for transmitting documents.
(eXtensible Markup Language) Contains much metadata that can be used to validate the
format and completeness of the document, but includes
considerable overhead (see Figure 6-15a).
JSON A markup language used for transmitting documents.
(JavaScript Object Notation) Contains little metadata and is preferred for transmitting
volumes of data between servers and browsers. While the
notation is the format of JavaScript objects, JSON documents
can be processed by any language (see Figure 6-15b).