Cisco’s exams can be a lot of hard work- we know. But the worst thing you can do to yourself is to simply look up the answers to exam questions. Not only do you not learn anything- but you’re hurting your future in the process.
Instead, shouldn’t you get a helpful hint and get pointed in the right direction of where to look for an answer? That way, you can keep your dignity, hopes for the future, and of course your grade. The questions below are from the CCNA 1 module 6 exam- but instead of straight answers, we reason out why the answers are correct. If any type of math or decision making is involved, we leave that up to you (But we will of course give you the resources you need to complete the question.)
Refer to the exhibit. Host A is communicating with host F. What happens to a frame sent from host A to host F as it travels over the Ethernet segments?
A) The frame format is modified as it passes through each switch.
B) The frame format remains the same across each Ethernet segment.
C) The frame format is modified as the media speed changed at switch B and switch E.
D) The frame format is modified as the media material changes between copper and fiber at switch C and switch D.
More Info: How the Network Access Layer Works
Explanation: The frame format is not modified at any point to its destination, so B is the correct answer.
2. How many hexadecimal digits are in a MAC address?
A) 2
B) 8
C) 12
D) 16
E) 32
More Info: A Guide to Network Math
Explanation: Hexadecimal is outlined in the above article, and we will find from reading it that there are 12 digits in a hexadecimal MAC address. C is the correct answer.
3. What are three functions of a NIC in a PC? (Choose three.)
A) A NIC connects the PC to the network media.
B) A NIC detects collisions on the Ethernet segment.
C) A NIC checks the formatting of data before it is transmitted.
D) A NIC passes the contents of selected frames to the upper OSI layers.
E) A NIC acknowledges and retransmits data that was not received properly.
F) A NIC discards frames when the destination IP address does not match the local host.
More Info: What is a Network Interface Card?
Explanation: The NIC connects a PC to network media, so A is correct. It also detects collisions, so B is also correct. A NIC is too dumb of a device to check formatting, so C is incorrect. NICs do indeed pass information to upper OSI layers, so D is correct. D and E are both untrue since NICs do not have these responsibilities.
4. At what layer of the OSI model does a MAC address reside?
A) 1
B) 2
C) 3
D) 4
E) 7
More Info: How the Network Access Layer Works
Explanation: The second layer of the OSI model is the Data link layer (which corresponds to the TCP/IP network access layer). We know that the data link layer is responsible for MAC address capability, so B is the correct answer.
5. A router has an Ethernet, Token Ring, serial, and ISDN interface. Which interfaces will have a MAC address?
A) serial and ISDN interfaces
B) Ethernet and Token Ring interfaces
C) Ethernet and ISDN interfaces
D) Token Ring and serial interfaces
More Info: (none)
Explanation: The MAC address is reserved for the Ethernet and Token Ring interfaces, so B is correct. Serial and ISDN interfaces do not require MAC addresses, so the remaining answers are incorrect.
6. In an Ethernet LAN, how does the NIC know when it can transmit data?
A) An Ethernet NIC transmits data as soon as the frame is received.
B) An Ethernet NIC transmits data as soon as the NIC receives a token.
C) An Ethernet NIC transmits data when it senses a collision.
D) An Ethernet NIC transmits data after listening for the absence of a signal on the media.
More Info: What is a Network Interface Card?
Explanation: NICs look for an absence in signal before transmitting, since we need an open spot on the network to transmit or there will be collisions. D is the correct answer.
7. Which characteristics describe carrier sense multiple access collision detect (CSMA/CD)? (Choose three.)
A) reliable
B) point-to-point
C) nondeterministic
D) connection-oriented
E) collision environment
F) first-come, first-served approach
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: CSMA/CD is a first come first serve approach, as stated in the above article- F is correct.. This is basically defining nondeterministic, so C is correct too. CSMA/CD works with the collision environment, so E is also true.
8. Which two devices can provide full-duplex Ethernet connections? (Choose two.)
A) hub
B) modem
C) repeater
D) NIC
E) Layer 2 switch
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: This question is rather tricky. It is best to eliminate the wrong answers first. Hubs can’t, since they don’t support microsegmentation. Modems operate as half-duplex, so they are out too. Repeaters are unrelated to the matter, so it leaves us with the NIC and Layer 2 switch. D and E are correct.
9. On a local area network, one workstation can send data on the line while it is receiving data. What type of data transfer does this describe?
A) hybrid
B) half duplex
C) full duplex
D) multilink
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: This is a full-duplex communication since both devices can transmit and receive simultaneously. C is the correct answer.
10. Refer to the exhibit. The small office network shown in the exhibit consists of four computers connected through a hub. Which configuration would cause collisions and errors on the network?
A) autonegotiation
B) FastEthernet
C) peer-to-peer shared resources
D) administratively configured full duplex
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: D is the correct answer, since the device connecting the computers is a hub. We can not have an error-free network operating at full-duplex with a hub. If the device was a switch, it would be a different story.
11. Refer to the exhibit. The switch and workstation are administratively configured for full-duplex operation. Which statement accurately reflects the operation of this link?
A) No collisions will occur on this link.
B) Only one of the devices can transmit at a time.
C) The switch will have priority for transmitting data.
D) The devices will default back to half duplex if excessive collisions occur.
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: Since full-duplex operation allows two devices send and receive information at the same time, there should be no collisions at all. The device is a switch (not a hub), so there should be no further problems. A is the correct answer.
12. Refer to the exhibit. All hosts are in listen mode. Host 1 and Host 4 both transmit data at the same time. How do the hosts respond on the network? (Choose two.)
A) Hosts 1 and 4 may be operating full duplex so no collision will exist.
B) The hub will block the port connected to Host 4 to prevent a collision.
C) After the end of the jam signal, Hosts 1, 2, 3, and 4 invoke a backoff algorithm.
D) Hosts 1 and 4 are assigned shorter backoff values to provide them priority to access the media.
E) If a host has data to transmit after the backoff period of that host, the host checks to determine if the line is idle, before transmitting.
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: We know from the above article that when a collision occurs, a jam signal is sent and all devices invoke a back-off algorithm. After that time is up, hosts may then check the network for traffic. If it is open, the device may transmit. This describes answers C and E.
13. When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?
A) The hosts return to a listen-before-transmit mode.
B) The hosts creating the collision have priority to send data.
C) The hosts creating the collision retransmit the last 16 frames.
D) The hosts extend their delay period to allow for rapid transmission.
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: After the back-off algorithm is expired, all devices go bck to normal (listening before transmitting). A is the correct answer.
14. Which statement describes how CSMA/CD on an Ethernet segment manages the retransmission of frames after a collision occurs?
A) The first device to detect the collision has the priority for retransmission.
B) The device with the lowest MAC address determines the retransmission priority.
C) The devices on the network segment hold an election for priority to retransmit data
D) The devices transmitting when the collision occurs DO NOT have priority for retransmission.
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: After a back-off sequence is expired, the devices that were in the collision do not have priority to transmit data. D is the correct answer.
15. Refer to the exhibit. A technician wants to increase the available bandwidth for the workstation by allowing the switch and the NIC on the workstation to transmit and receive simultaneously. What will permit this?
A) CSMA/CD
B) full-duplex
C) FastEthernet
D) crossover cable
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: This is only applicable via a full-duplex connection, B is correct.
16. Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?
A( A random delay is used to ensure a collision-free link.
B) A random delay value for each device is assigned by the manufacturer.
C) A standard delay value could not be agreed upon among networking device vendors.
D) A random delay helps prevent the stations from experiencing another collision during the transmission.
More Info: Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
Explanation: This random delay helps prevent every computer on the network transmitting at the same time after the back-off algorithm is expired. Since it’s random for each device, collisions are unlikely. D is the correct answer.
17. In which two layers of the OSI model does Ethernet function? (Choose two.)
A) application
B) session
C) transport
D) network
E) data link
F) physical
More Info: How the Network Access Layer Works
Explanation: The bottom two layers of the OSI model deal with Ethernet functions-Physical and Data Link. Note that this is also the Network Access Layer in the TCP/IP model. E and F are both correct.
18. Which of the following are specified by IEEE standards as sublayers of the OSI data link layer? (Choose two.)
A) Logical Link Control
B) Logical Layer Control
C) Media Access Control
D) Logical Link Communication
E) Media Access Communication
F) Physical Access Communication
More Info: How the Network Access Layer Works
Explanation: Sublayers of the Data Link layer include Logical Link Control (LLC) and Media Access Control (MAC). A and C are both correct.
19. Where does the MAC address originate?
A) DHCP server database
B) configured by the administrator
C) burned into ROM on the NIC card
D) network configuration on the computer
E) included in the creation of the processor chip
More Info: What is a Network Interface Card?
Explanation: The MAC address is burned into the NIC at the factory- C is the correct answer.
