Ch. 2 - Application Layer Flashcards
HTTP
HyperText Transfer Protocol - the protocol used for transmitting web pages over the Internet
TLS
Transport Layer Security provides encrypted TCP connections, data integrity, and end-point authentication.
Stateless HTTP
Server maintains no information about past client requests.
Web client
Browser that requests, receives (using HTTP protocol), and “displays” Web objects
Web server
Sends objects (using HTTP protocol) in response to requests.
Web page objects
e.g. HTML files, JPEG images, Java applets, audio files, etc.
Why are protocols that maintain “state” complex?
- Past history must be maintained
- If server/client crashes, their views of “state” may be inconsistent and must be reconciled
What are the two types of HTTP connections?
Non-persistent HTTP:
- At most one object is sent over a TCP connection
- Downloading multiple objects requires multiple connections
Persistent HTTP:
- Multiple objects can be sent over a single TCP connection between client and server.
Socket
Process that connects an application with a network protocol.
P2P Architecture
No always-on server; arbitrary end-systems directly communicate; peers request service from other peers, provide service in return; peers are intermittently connected and change IP addresses
Client-Server Architecture
Client computers use a centrally administered, always-on server to share data, data storage space, and devices.
Process
A program that is running within an end system
FTP
File Transfer Protocol: uses a TCP-based network to pass files from host to host.
Web Cache
A file that stores copies of Web pages to make frequently accessed pages load faster. (a.k.a. Proxy Server)
Define CDN
Content Delivery Network: a network of servers that deliver web content to users from locations closest to them, improving performance and reliability.