Cisco Certified Support Technician (CCST) Networking 100-150 Dumps in PDF

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

Explanation:

Explanation:

Correct Answer is : A. Transport
The Transport layer is responsible for end-to-end communication between applications. It encapsulates application data into segments (TCP) or datagrams (UDP) and adds source and destination port numbers to identify the specific processes on each host. This segmentation is what enables multiplexed communication, allowing multiple applications to share the same network connection.
Why other layers are not correct
Data Link (B) – Handles frames and uses MAC addresses, not port numbers; segmentation here is limited to bits on the physical medium. Session (C) – Manages logical connections and dialog control, but it does not add port identifiers to the data units. Network (D) – Provides logical addressing (IP) and routing; segmentation is performed by IP packets, which lack port numbers.

Reference:

Cisco CCST Study Guide – OSI Model Overview ( https://www.cisco.com/c/en/us/training-events/training-certifications/certifications/ccast.html ) RFC 793 – Transmission Control Protocol (TCP) ( https://datatracker.ietf.org/doc/html/rfc793 )

Explanation:

Explanation
Correct answer – ICMPv6 IPv6 stations use ICMPv6 (specifically the Router Advertisement and Neighbor Discovery messages) to discover routers, learn the network prefix, and obtain the default gateway automatically. These messages carry the prefix information that enables stateless address autoconfiguration (SLAAC) , allowing a host to generate its own IPv6 address without any server interaction.
Why the other options are unsuitable

A: DHCPv6 – provides stateful address assignment and additional options (e.g., DNS servers). It requires a DHCPv6 server and does not rely on ICMPv6 for address autoconfiguration, making it less efficient for pure SLAAC.
B: DNS – resolves hostnames to IP addresses but has no role in allocating or deriving IPv6 addresses.
D: TFTP – is a simple file-transfer protocol used for bootstrapping devices; it is unrelated to address configuration.
Conclusion – The automatic, stateless IPv6 address configuration mechanism is defined in the IPv6 neighbor discovery protocol, which operates over ICMPv6 . Therefore, option C is the most appropriate answer.

Reference:

RFC 4861 – Stateless Address Autoconfiguration for IPv6 Cisco CCNA 200-301 Official Cert Guide, Chapter 5 – IPv6 Addressing and Autoconfiguration.

Explanation:

Explanation:

Explanation:

Explanation:

The CIDR (Classless Inter-Domain Routing) notation provides a concise way to represent an IP address and its associated subnet mask by indicating the number of bits in the network portion of the address. To determine the CIDR prefix for the given IP address 172.16.100.25 and subnet mask 255.255.252.0, we must convert the subnet mask into its binary equivalent.
The first octet of the subnet mask, 255, translates to eight consecutive binary ones (11111111). Similarly, the second octet, 255, also represents eight consecutive binary ones (11111111). The third octet, 252, is critical for this calculation; in binary, 252 is expressed as 11111100, contributing six consecutive binary ones. Finally, the fourth octet, 0, translates to eight binary zeros (00000000), which do not contribute to the count of network bits.
When combined, the full binary representation of the subnet mask 255.255.252.0 is 11111111.11111111.11111100.00000000. The CIDR prefix length is determined by counting the total number of consecutive '1' bits from the left in this binary subnet mask. Adding the '1' bits from each octet, we get 8 (from the first 255) + 8 (from the second 255) + 6 (from 252) + 0 (from 0), which totals 22.
Therefore, the CIDR prefix length for this subnet mask is /22. Combining this with the given IP address, 172.16.100.25, the complete CIDR notation becomes 172.16.100.25/22. This calculation directly matches option B.
In cloud computing environments, understanding CIDR notation is fundamental for designing and configuring virtual private clouds (VPCs), virtual networks (VNETs), and their constituent subnets. Cloud providers extensively leverage CIDR blocks to define the IP address ranges for customer networks, ensuring efficient resource allocation and preventing IP address conflicts across various services. This knowledge is vital for network architects and engineers to effectively segment cloud resources, implement routing, and apply network security policies. For instance, when provisioning a VPC in Amazon Web Services (AWS) or a VNet in Microsoft Azure, specifying a CIDR block is a mandatory step to define its entire address space. Correctly calculating CIDR prefix lengths is essential for robust network design, as it directly impacts the number of available hosts and the scalability of subnets.
Further research into subnetting and CIDR can be found through authoritative resources like Cisco's documentation and cloud provider guides.
Authoritative Links for Further Research:
Cisco IP Addressing and Subnetting for New Users: https://www.cisco.com/c/en/us/support/docs/ip/ip-protocols/13788-3.html AWS VPCs and Subnets: https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Subnets.html Azure Virtual Network IP Addressing: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-ip-addresses-overview-vnet