Lecture 3. Application Layer. B1Chapters 15 Flashcards
(18 cards)
Q: Which layers of the OSI model correspond to the TCP/IP application layer?
A: The application, presentation, and session layers of the OSI model.
Q: What is the main purpose of the application layer in networking?
A: It provides the interface between end-user applications and the underlying network to transmit messages.
Q: Name some of the most widely used application layer protocols.
A: HTTP, FTP, TFTP, IMAP, DNS.
Q: What are the main functions of the presentation layer?
A:
Formatting or presenting data
Data compression
Data encryption and decryption
Q: What does the session layer do?
A:
Creates and maintains dialogs (sessions) between applications
Handles setup, coordination, and termination of sessions
Keeps data properly synchronized and organized during communication
Q: What is HTTP and what type of protocol is it?
A: HTTP (HyperText Transfer Protocol) is a request/response protocol for web communication.
Q: What are the three common HTTP methods and their purposes?
A:
GET: Requests data from a server (e.g., asks for a web page)
POST: Submits data to a server (e.g., form data)
PUT: Uploads or replaces resources on a server (e.g., file upload)
Q: What are the main protocols used for email?
SMTP: Used to send emails
POP and IMAP: Used by clients to receive emails
Q: What is the purpose of DNS?
A: DNS (Domain Name System) translates human-readable domain names into numeric IP addresses.
Q: What are some tools or commands to interact with DNS?
A:
- nslookup (command to query DNS)
- ipconfig /displaydns (shows DNS cache on Windows)
Q: What is DHCP and what does it do?
A: DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, gateways, and other network parameters to devices.
Q: What is FTP and what are its basic commands?
A: FTP (File Transfer Protocol) is used to transfer files between computers.
- ftp <ip>: Open FTP session
- dir: List all directories and files on the server
- get: Download files from the server
- put: Upload files to the server</ip>
Q: What is TFTP and how does it differ from FTP?
A: TFTP (Trivial File Transfer Protocol) is a simpler protocol than FTP, typically used for transferring small files without authentication.
Q: What is SMB and what is it used for?
A: SMB (Server Message Block) is a protocol for sharing files, printers, and other resources over a network.
What is the role of the application, presentation, and session layers in client-server communication?
- Application layer: Provides user interface and application services
- Presentation layer: Ensures data is in a usable format (formatting, encrypting, compressing)
- Session layer: Manages sessions, establishes and maintains connections
Q: Why were domain names created?
A: To provide a simple, recognizable way for humans to access networks, instead of using numeric IP addresses.
Q: What is the interface that the application layer provides?
A: The interface between user/business applications and the network.
Q: What is the function of an email server and client?
A:
- Email server: Stores emails and manages their transmission
- Email client: Communicates with the server to send and receive messages
