At which OSI layer is the data stream broken up into segments that include source and destination port numbers?
Answer(s): A
Correct Answer is : A. TransportThe 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 correctData 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.
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 )
Which protocol is used by IPv6-enabled hosts to perform automatic stateless address configuration?
Answer(s): C
ExplanationCorrect 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 unsuitableA: 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.
RFC 4861 – Stateless Address Autoconfiguration for IPv6 Cisco CCNA 200-301 Official Cert Guide, Chapter 5 – IPv6 Addressing and Autoconfiguration.
DRAG DROP (Drag and Drop is not supported) Move each protocol or device type from the list on the left to the correct OSI layer on the right.
HOTSPOT (Drag and Drop is not supported)-For each statement about bandwidth and throughput, select True or False. Note: You will receive partial credit for each correct selection.
DRAG DROP (Drag and Drop is not supported) Move each network category on the left to its correct definition on the right.
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