W2 - Application Layer I Flashcards
What are the main components of the Internet?
Hosts, communication links, packet switches, and protocols.
What are communication links determined by?
Bandwidth, which can include fiber, copper, radio, and satellite.
What do packet switches do?
They forward packets of data through routers and switches.
What is the Internet?
A network of interconnected networks connected through ISPs.
What controls message exchanges on the Internet?
Protocols such as TCP, IP, and HTTPS.
What are RFCs and IETF in the context of Internet standards?
RFC: Request for Comments, which define protocols and standards. IETF: Internet Engineering Task Force, which develops and promotes these standards.
What is a protocol in networking?
A set of rules defining the format, order of messages sent and received, and the actions taken on message receipt.
What are the six protocol layers listed in the document?
- Hosts 2. Routers 3. Links of various media 4. Applications 5. Protocol 6. Hardware & Software
What are the main protocol stack layers in the ISO/OSI model?
Application, Transport, Network, Link, Physical, Presentation, Session
What does the link layer handle?
Data transfer between neighboring network elements via communication mediums like Ethernet, 802.11, and PPP.
What does the physical layer manage?
Transmission of bits on the wire.
What is the function of the presentation layer?
Allows applications to interpret data through encryption, decryption, and compression.
What is the role of the session layer?
Synchronization, checkpointing, and recovery of data exchange.
What are examples of network applications?
FTP, SMTP, HTTPS.
What must a network application be capable of?
Running on different client systems and communicating over the network.
What is a Client-Server architecture?
An architecture where: The server is always on with a permanent IP address. Clients communicate with the server and do not communicate directly with each other.
What is Peer-to-Peer (P2P) architecture?
An architecture without an always-on server where peers communicate directly and scale by adding new peers.
What is a process in networking?
A program running within a host that communicates either via inter-process communication (within the same host) or messages (between hosts).
What is the difference between a client process and a server process?
Client process: Initiates communication. Server process: Waits to be contacted.
What is the role of a socket in communication?
It is the interface through which a process sends and receives messages.
What information does an addressing process require?
A 32-bit IP address, IP addresses of both machines, and port numbers.
What does the App-Layer Protocol define?
- Types of messages exchanged (e.g., request, response). 2. Message syntax. 3. Message semantics. 4. Rules for message processing. 5. Open protocols for interoperability.
What transport service features do applications need?
Data integrity, throughput, timing, and security.
What are the main features of TCP?
Reliable transport, flow control, congestion control, and connection-oriented setup.
What does TCP not provide?
Timing, minimum throughput guarantees, and security.
What are the characteristics of UDP?
Unreliable data transfer without reliability, flow control, congestion control, timing, throughput guarantee, security, or connection setup.
Why is standard TCP considered insecure?
It sends cleartext passwords that traverse the Internet in plaintext.
How does TSL/SSL secure TCP?
By providing encrypted TCP connections, data integrity, and endpoint authentication.
Where is SSL implemented?
At the application layer through libraries that encrypt cleartext passwords before transmission.
