HTTP (The Hypertext Transfer Protocol)
User Agent
Kind of browser
Tim Berners-Lee
Knighted by Queen Elizabeth for his invention of the World Wide Web. He also invented HTTP and HTML.
Transport
Make client-server connections and optionally control transmission speed, check for errors, etc
Content-Type
Mime type
Accept
Mime types which browser can accept
Content-Length
Number of bytes
Query
Query string for a CGI program
Weak entity tag
Changes only when semantics of entity-body changes
Strong entity tag
Changes when any portion of resource changes
Application
Do useful work like Web browsing, email, and file transfer
Content-Language
English, for example
Physical
Specify what medium connects two nodes, how binary ones and zeros are differentiated, etc
Scheme
The protocol you are using
HTTP: hypertext transfer protocol
The rules governing the conversation between a Web client and a Web server
Server
Type of server
Port
TCP port number that protocol server is using
Path
Path and filename reference of object on server
Data Link
Route data packets within the local area network
Internet
Route packets between networks
Post
Sends information to be stored on server or as input to script
Put
Sends new copy of existing object to server
Communication
Server tells client what type of information is coming before information arrives
Parameters
Any specific parameters that object needs
Content-Encoding
Data compression
Date
Date and time
Expires
Date when file becomes invalid
Last-Modified
Date when last modified
HTML: hypertext markup language
Definitions of tags that are added to Web documents to control their appearance
Delete
Deletes object
Lower Layers
Handle communication between the client and server
Host
Host name or IP number
Fragment
Reference to a subset of an object
Head
Returns information about object
Get
Returns object
If-Modified-Since
Returns object only if more recent than given date Otherwise returns status code 304
Network Protocol
The set of rules governing a conversation between a client and a server
Protocol
The set of rules governing a conversation between people
Gateways
Translates from one protocol or service to another
Authorization
User password
Scripts
• Translates input from client • Calls other programs • Translates output from programs and returns it to client