Networking - Internetworking

Exercise :: Internetworking - Internetworking

  • Internetworking - Internetworking
11. 

How does a host on an Ethernet LAN know when to transmit after a collision has occurred?

  1. In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.
  2. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.
  3. You can improve the CSMA/CD network by adding more hubs.
  4. After a collision, the station that detected the collision has first priority to resend the lost data.
  5. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.

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

Answer: Option D

Explanation:

Once transmitting stations on an Ethernet segment hear a collision, they send an extended jam signal to ensure that all stations recognize the collision. After the jamming is complete, each sender waits a predetermined amount of time, plus a random time. After both timers expire, they are free to transmit, but they must make sure the media is clear before transmitting and that they all have equal priority.

12. 

Which of the following types of connections can use full duplex?

  1. Hub to hub
  2. Switch to switch
  3. Host to host
  4. Switch to hub
  5. Switch to host

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

Answer: Option D

Explanation:

Hubs cannot run full-duplex Ethernet. Full duplex must be used on a point-to-point connection between two devices capable of running full duplex. Switches and hosts can run full duplex between each other, but a hub can never run full duplex.

13. 

Acknowledgments, sequencing, and flow control are characteristics of which OSI layer?

A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 7

Answer: Option C

Explanation:

A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably. A reliable connection is defined by a virtual circuit that uses acknowledgments, sequencing, and flow control, which are characteristics of the Transport layer (layer 4).

14. 

Which fields are contained within an IEEE Ethernet frame header?

  1. Source and destination MAC address
  2. Source and destination network address
  3. Source and destination MAC address and source and destination network address
  4. FCS field

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

Answer: Option A

Explanation:

An Ethernet frame has source and destination MAC addresses, an Ether-Type field to identify the Network layer protocol, the data, and the FCS field that holds the answer to the CRC.

15. 

What type of RJ45 UTP cable do you use to connect a PC's COM port to a router or switch console port?

A. Straight-through
B. Crossover cable
C. Crossover with a CSU/DSU
D. Rolled

Answer: Option D

Explanation:

To connect to a router or switch console port, you would use an RJ45 UTP rolled cable.