Networking - TCP/IP

Exercise :: TCP/IP - TCP/IP

  • TCP/IP - TCP/IP
11. 

Which of the following is the decimal and hexadecimal equivalents of the binary number 10011101?

A. 155, 0x9B
B. 157, 0x9D
C. 159, 0x9F
D. 185, 0xB9

Answer: Option B

Explanation:

To turn a binary number into decimal, you just have to add the values of each bit that is a 1. The values of 10011101 are 128, 16, 8, 4, and 1. 128 + 16 + 8 + 4 + 1 = 157.

Hexadecimal is a base-16 number system. The values of hexadecimal are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F-16 characters total, from which to create all the numbers you'll ever need. So, if 1001 in binary is 9, then the hexadecimal equivalent is 9. Since we then have 1101, which is 13 in binary, the hexadecimal answer is D and the complete hexadecimal answer is 0x9D.


12. 

Which statements are true regarding ICMP packets?

  1. They acknowledge receipt of a TCP segment.
  2. They guarantee datagram delivery.
  3. They can provide hosts with information about network problems.
  4. They are encapsulated within IP datagrams.

A. 1 only
B. 2 and 3
C. 3 and 4
D. 2, 3 and 4

Answer: Option C

Explanation:

Internet Control Message Protocol (ICMP) is used to send error messages through the network, but they do not work alone. Every segment or ICMP payload must be encapsulated within an IP datagram (or packet).

13. 

Which of the following are layers in the TCP/IP model?

  1. Application
  2. Session
  3. Transport
  4. Internet
  5. Data Link
  6. Physical

A. 1 and 2
B. 1, 3 and 4
C. 2, 3 and 5
D. 3, 4 and 5

Answer: Option B

Explanation:

This seems like a hard question at first because it doesn't make sense. The listed answers are from the OSI model and the question asked about the TCP/IP protocol stack (DoD model). However, let's just look for what is wrong. First, the Session layer is not in the TCP/IP model; neither are the Data Link and Physical layers. This leaves us with the Transport layer (Host-to-Host in the DoD model), Internet layer (Network layer in the OSI), and Application layer (Application/Process in the DoD).

14. 

Which layer 4 protocol is used for a Telnet connection?

A. IP
B. TCP
C. TCP/IP
D. UDP

Answer: Option B

Explanation:

Although Telnet does use TCP and IP (TCP/IP), the question specifically asks about layer 4, and IP works at layer 3. Telnet uses TCP at layer 4.

15. 

Which statements are true regarding ICMP packets?

  1. ICMP guarantees datagram delivery.
  2. ICMP can provide hosts with information about network problems.
  3. ICMP is encapsulated within IP datagrams.
  4. ICMP is encapsulated within UDP datagrams.

A. 1 only
B. 2 and 3
C. 1 and 4
D. All of the above

Answer: Option B

Explanation:

ICMP is used for diagnostics and destination unreachable messages. ICMP is encapsulated within IP datagrams, and because it is used for diagnostics, it will provide hosts with information about network problems.