CCNA MODULES 1-3 EXAM PRACTICE QUESTIONS AND ANSWERS. VERIFIED 2026.

CCNA MODULES 1-3 EXAM PRACTICE
QUESTIONS AND ANSWERS. VERIFIED
2026.




What does TCP stand for? - ANS Transmission Control Protocol


What does IP stand for? - ANS Internet Protocol


What does OSI stand for? - ANS Open Systems Interconnection


What is step 1 of the encapsulation process? - ANS Create application data and headers


What is step 2 of the encapsulation process? - ANS Package data for transport


What is step 3 of the encapsulation process? - ANS Add destination and source network
address


What is step 4 of the encapsulation process? - ANS Add destination and source data link
address


What is step 5 of the encapsulation process? - ANS Transmit the bits



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,What is the first layer of the OSI reference model? - ANS Physical


What is the second layer of the OSI reference model? - ANS Data Link


What is the third layer of the OSI reference model? - ANS Network


What is the fourth layer of the OSI reference model? - ANS Transport


What is the fifth layer of the OSI reference model? - ANS Session


What is the sixth layer of the OSI reference model? - ANS Presentation


What is the seventh layer of the OSI reference model? - ANS Application


What is the first layer of the TCP/IP reference model? - ANS Network Interface


What is the second layer of the TCP/IP reference model? - ANS Internetwork


What is the third layer of the TCP/IP reference model? - ANS Transport


What is the fourth layer of the TCP/IP reference model? - ANS Application


What is a L3PDU? - ANS Layer 3 protocol data unit, which would be the layer 3 headers,
trailers, and all data encapsulated inside


What terms describe the contents of data encapsulated by the data link, network, and transport
layers, respectively? - ANS Frame, packet, and segment


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, What are the benefits of layering? - ANS Easier to learn and develop, Multivendor
Interoperability, Modular Engineering


What header or trailer does a router discard as a side-effect of routing? - ANS The data-link
header and trailer


Which pins are used by an Ethernet NIC to send? - ANS Pins 1 and 2


Which pins are used by an Ethernet NIC to receive? - ANS Pins 3 and 6


What are the typical functions defined by physical layer protocols? - ANS 1. Cabling (defines
the number of wires and type of shielding) 2. Connectors (Defines shape of connector and
number of pins) 3. Pins (Defines the purpose of pins) 4. Voltage and Current (Defines electrical
characteristics of the endpoint devices) 5. Encoding (Defines how a device signals a binary 1 or 0
onto the transmit pin)


Why are the wires twisted into pairs in electrical cables? - ANS Twisting pairs of wires reduces
electromagnetic interference cause by the electrical current.


What is attenuation? - ANS Attenuation is the tendency of electical current to grow weaker
the farther it has to travel.


What are the typical functions defined by data link layer protocols? - ANS . Arbitration
(Determines when it is appropriate to use the physical medium) 2. Addressing (Ensures that the
correct recipient receives and processes the data) 3. Error Detection (Determines whether the
data made the trip across the physical medium successfully) 4. Identification of the
encapsulated data (Determines the type of header that follows the data link header)


What does CSMA/CD stand for? - ANS Carrier Sense Multiple Access with Collision Detection.
It is the algorithm that helps devices in half duplex mode avoid collisions.


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