Cisco 100-150 Exam Prep
Cisco Certified Support Technician (CCST) Networking (Page 4 )

Updated On: 12-Sep-2026

DRAG DROP (Drag and Drop is not supported) Move each protocol from the list on the left to the correct TCP/IP model layer on the right.
Note: You will receive partial credit for each correct match.

  1. See Explanation section for answer.

Answer(s): A

Explanation:



DRAG DROP (Drag and Drop is not supported) Move each protocol from the list on the left to its correct example on the right.

  1. See Explanation section for answer.

Answer(s): A

Explanation:



During the data encapsulation process, which OSI layer adds a header that contains MAC addressing information and a trailer used for error checking?

  1. Network
  2. Transport
  3. Session
  4. Data Link

Answer(s): D

Explanation:

During the data encapsulation process, each layer of the OSI model adds specific control information to the data passed down from the layer above. The correct answer, Data Link (Layer 2), is responsible for handling communication between devices on the same local network segment.
The Data Link layer's primary function is to provide reliable data transfer across a physical link. It achieves this by taking network layer packets and encapsulating them into "frames." This framing process involves adding both a header and a trailer to the data.
Within the header added by the Data Link layer, essential information for local network communication is included, most notably the Media Access Control (MAC) address. MAC addresses are unique hardware identifiers assigned to network interfaces (like Ethernet cards) and are used to identify the source and destination devices directly connected within the same broadcast domain. This allows devices to communicate with each other on the same physical segment without needing to involve a router.
Furthermore, the Data Link layer adds a trailer to the end of the frame. This trailer typically contains a Frame Check Sequence (FCS) or Cyclic Redundancy Check (CRC). The FCS is a numerical value calculated from the frame's contents, designed for error detection.
When a receiving device gets a frame, it recalculates the FCS; if the calculated value doesn't match the one in the trailer, it indicates that the frame was corrupted during transmission and should be discarded.
In contrast, the Network layer (A) adds IP addresses for logical addressing and routing across different networks. The Transport layer (B) adds port numbers and manages end-to-end communication, ensuring reliable data transfer or connectionless services between applications. The Session layer (C) establishes, manages, and terminates connections between applications, focusing on dialogue control and synchronization. Therefore, the unique responsibility for MAC addressing and error-checking trailers resides squarely with the Data Link layer.

Authoritative Links for Further Research:
Cisco's OSI Model Overview: https://www.cisco.com/c/en/us/support/docs/lan-switching/ethernet/116223-technote-ethernet-00.html GeeksforGeeks - Data Link Layer: https://www.geeksforgeeks.org/data-link-layer/ (While not a direct standard body, it provides a clear, well-regarded explanation of fundamental concepts often cited in educational contexts). IEEE 802 Local and Metropolitan Area Network Standards: https://standards.ieee.org/project/802.html (This is the standards body that defines many Data Link Layer technologies like Ethernet and Wi-Fi, which heavily rely on MAC addresses and error checking).



Which protocol does an IPv6 host use to resolve the MAC address associated with a destination IPv6 address?

  1. Neighbor Discovery Protocol (NDP)
  2. Cisco Discovery Protocol (CDP)
  3. Dynamic Host Configuration Protocol (DHCP)
  4. Address Resolution Protocol (ARP)

Answer(s): A

Explanation:

Correct option: A – Neighbor Discovery Protocol (NDP)
NDP is defined in RFC 4861 and is the IPv6 counterpart to ARP. It performs address resolution, neighbor discovery, and duplicate-address detection, enabling an IPv6 host to map a destination IPv6 address to the corresponding link-layer (MAC) address. The process uses ICMPv6 Neighbor Solicitation/Advertisement messages; the host sends a solicitation to the target address and receives an advertisement that contains the target’s MAC address. This is the standard, IPv6-native mechanism for MAC-address resolution.

Why the other options are unsuitable
B: Cisco Discovery Protocol (CDP) – a Cisco-proprietary Layer-2 discovery protocol used to exchange device information; it does not resolve IP addresses to MAC addresses.
C: Dynamic Host Configuration Protocol (DHCP) – provides IP configuration parameters (e.g., address, mask, gateway) but never performs address-to-MAC mapping for packet forwarding.
D: Address Resolution Protocol (ARP) – is defined for IPv4 only; IPv6 does not use ARP for address resolution, instead relying on NDP.
Key takeaway For IPv6, the protocol designed to resolve a destination IPv6 address to its MAC address on the local link is NDP , making option A the only correct answer.


Reference:

1. RFC 4861 – Neighbor Discovery for IPv6 – https://datatracker.ietf.org/doc/html/rfc4861 2. Cisco Documentation – IPv6 Neighbor Discovery – https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6_neighbor_discovery/configuration/xe-3s/ips-xe-3s-book/ndp.html



DRAG DROP (Drag and Drop is not supported) Move each cloud service model on the left to its correct description on the right.

  1. See Explanation section for answer.

Answer(s): A

Explanation:



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