Application Layer l

Question 1

What is a protocol?

Answer 1

A set of rules or procedures for transmitting data between devices

Question 2

5 layer protocols

Answer 2

Application
Transport
Network
Link
Physical

Question 3

Application layer

Answer 3

End-user interaction; supports apps (HTTP, FTP)

Question 4

Transport layer

Answer 4

Process data transfer (TCP, UDP)

Question 5

Network layer

Answer 5

Routes data from source to destination (IP, routing protocols)

Question 6

Link layer

Answer 6

Local data transfer between neighbouring network elements (MAC, Ethernet, WiFi)

Question 7

Physical layer

Answer 7

Any physical component on the wire (copper/optical cable)

Question 8

Presentation layer

Answer 8

Translates data (encrypt/decrypt, compression)

Question 9

Session layer

Answer 9

Manages sessions between apps; opening/closing mechanism

Question 10

TCP & UDP

Answer 10

no encryption, cleartext passwords sent into socket traverse Internet in cleartext

Question 11

TLS/SSL

Answer 11

provides encrypted connection (https), data integrity, end-point authentication

Question 12

TCP service

Answer 12

reliable delivery, flow/congestion control, does not provide timing or security, connection oriented, slower speed, resends lost packets

Question 13

UDP service

Answer 13

unreliable data transfer, connectionless, faster speed, no error checking

Question 14

What happens when you visit a secure website?

Answer 14

1. Application Layer uses HTTP
2. TLS encrypts HTTP data
3. TCP ensures reliable delivery of that encrypted data