CHAPTER 1 KEY TOPICS

Question 1

What is Same-layer interaction on different computers?

Answer 1

The 2 computers use a protocol to communicate with the same layer on another computer.

Question 2

What is Adjacent-layer interaction on the same computers?

Answer 2

On a single computer, one layer provides a service to a higher layer

Question 3

What are the 4 steps if Larry uses Ethernet to forward an IP packet to Router R1?

Answer 3

1. Larry encapsulates the IP packet between an Ethernet header and Ethernet trailer, creating an Ethernet frame
2. Larry physically transmits the bits of the frame using electricity over the Ethernet cabling.
3. Router R1 physically receives the electrical signal over a cable, and re-creates the same bits by interpreting the meaning of the electrical signals.
4. Router R1 deencapsulates the IP packet from the Ethernet frame by removing and discarding the Ethernet header and footer.

Question 4

Describe the path for basic routing between 2 workstations of 2 separate networks.

Answer 4

1. Workstation 1 sends data to Router 1.
2. Router 1 acts as a post office and determines which route to forward the data to.
3. Router 2 receives the data and determines the route to send it to reach workstation 2

Question 5

What are the 5 steps of encapsulation?

Answer 5

1. Create and encapsulate the application data with any required application layer header.
2. Encapsulate the data supplied by the application layer inside a transport layer header.
3. Encapsulate the data supplied by the transport layer in side a network layer (IP) header.
4. Encapsulate the data supplied by the network layer inside a data link layer header and footer.
5. Transmit the bits.

Question 6

Identify the TCP/IP message in the Transport layer of the TCP/IP module.

Answer 6

Segment

Question 7

Identify the TCP/IP message in the Network layer of the TCP/IP module.

Answer 7

Packet

Question 8

Identify the TCP/IP message in the Data link of the TCP/IP module.

Answer 8

Frame

Question 9

how many layers are there in the OSI module?

Answer 9

7

Question 10

What are the 7 layers of the OSI model?

Answer 10

Application, Presentation, Session, Transport, Network, Data link, Physical

Question 11

What are the 4 layers of the 4-layer TCP/IP Model?

Answer 11

Application, Transport, Internet, Link

Question 12

What are the 5 layers of the 5-layer TCP/IP Model?

Answer 12

Application, Transport, Network, Data link, Physical

Question 13

What are 6 benefits to using a layered protocol specification?

Answer 13

Less complex, 
Standard interfaces, 
Easier to learn, 
Easier to develop, 
Multivender interoperability, 
Modular engineering

Question 14

What is deencapsulation?

Answer 14

The process in which a device interprets the lower layer headers, removes the previous header to reveal the next higher PDU.

Question 15

What encapsulation?

Answer 15

The process of taking data from a higher layer and placing a header and sometimes a trailer of the next lower layer.

Question 16

What is protocol data unit (PDU)?

Answer 16

A generic term for the header, data, and sometimes trailer of a layer.