Network+ OSI Model Layers and Functions Flashcards

A network technician is analyzing a packet capture and sees ARP broadcasts. At which OSI layer does ARP primarily operate?

Answer: Layer 2

ARP (Address Resolution Protocol) operates at Layer 2 (Data Link layer), resolving IP addresses to MAC addresses for local delivery.

Which Application layer protocol is used for sending email between mail servers?

Answer: SMTP

SMTP (Simple Mail Transfer Protocol) is used to transfer email messages between mail servers at the Application layer.

A Layer 3 switch combines the functionality of which two devices?

Answer: Switch and router

A Layer 3 switch combines the high-speed port density of a switch with the routing capability of a router for inter-VLAN routing.

Which OSI layer is responsible for converting bits into signals suitable for the transmission medium (electrical, optical, or radio)?

Answer: Physical layer

The Physical layer (Layer 1) converts binary data into signals appropriate for the transmission medium, whether copper, fiber, or wireless.

During the OSI encapsulation process, what is the correct order in which headers are added as data moves from Layer 7 to Layer 1?

Answer: Application header → Transport header → Network header → Data Link header

Headers are added sequentially as data moves down: Application layer first, then Transport (segment), Network (packet), then Data Link (frame).

Which of the following is an example of a Layer 4 protocol used for connectionless, low-latency transmissions?

Answer: UDP

UDP (User Datagram Protocol) is a connectionless Layer 4 protocol that sacrifices reliability for speed, ideal for streaming and DNS.

A network protocol that establishes, manages, and terminates connections between applications on different devices is functioning at which OSI layer?

Answer: Session layer

The Session layer (Layer 5) manages the lifecycle of communication sessions between applications, including establishment, maintenance, and termination.