1.5 Layering & Encapsulation

Question 1

5 layers of internet

Answer 1

1. application
2. transport
3. network
4. link
5. physical

Question 2

application layer definition

Answer 2

1st (top) layer of internet

the application’s distributed pieces exchange messages with each other

relies on services from the transport layer

supports network apps (HTTP, IMAP, SMTP, DNS)

Question 3

transport layer definition

Answer 3

2nd layer of internet

sends application-layer messages from one process to another

takes a message from the application layer and adds additional info to create a new data unit called a segment

TCP, UDP

Question 4

network layer definition

Answer 4

3rd layer of internet

transports data between hosts

encapsulates segments (from transport layer) with a new header to create a datagram

Question 5

link layer definition

Answer 5

4th layer of internet

communication link transfers data between 2 network devices

encapsulates datagram (network layer) to create a frame

WiFi, ethernet

Question 6

physical layer definition

Answer 6

5th (bottom) layer of internet

bits “on the wire” - controls the sending of bits on the link

Question 7

encapsulation definition

Answer 7

the process of taking a data unit from a higher layer and adding info to create a new data unit