Exercise 6.1

Create a diagram that shows the basic sequence of events involved in an HTTP interactive session. Include the following key elements.

• Client & Server
• DNS
• Proxies
• TCP/IP Connections
• HTTP requests & responses
• HTML Forms

Identify the likely implementations of the protocol running on the various nodes/objects.

Exercise 6.2

Explain the following HTTP topics with respect to your diagram.

1. Identify and explain the request methods & response codes.
2. Is state important for web apps? If so, how can it be implemented? If not, explain why not.
3. Explain the purpose and implementation of caching.
4. Identify and explain the techniques commonly used to secure the communications and to perform authentication & authorization.