Net+ Day 1 OSI Model Topologies and Cables

You are troubleshooting a network connectivity issue between two devices on the same floor. You suspect a physical layer problem. Which of the following cable types would be LEAST susceptible to electromagnetic interference (EMI)?

• Shielded Twisted-Pair (STP)
• Unshielded Twisted-Pair (UTP)
• Coaxial
• Fiber Optic

Answer explanation

STP provides an additional layer of shielding that helps to block EMI.

A user on your network reports extremely slow data transfer speeds when connecting to a wireless printer. You investigate and discover the wireless network is operating on the 2.4 GHz band, which is heavily congested with other devices. Which layer of the OSI model is responsible for addressing this issue?

• Physical
• Data Link
• Network
• Physical

Answer explanation

The Network layer is responsible for routing data packets across networks, including selecting the most appropriate channel for wireless communication.

Your company is designing a new office building and needs to decide on a network topology. They require a layout that is easy to expand and troubleshoot but may experience a single point of failure if a switch malfunctions. Which topology best meets these requirements?

• Bus
• Star
• Mesh
• Ring

Answer explanation

A star topology simplifies troubleshooting and expansion but relies on a central switch.

A technician needs to connect a new network device to the existing network. They identify the port on the switch as an RJ-45 jack. Which layer of the OSI model is responsible for the physical connection and data transmission across this port?

• Physical
• Data Link
• Network
• Transport

Answer explanation

The Physical layer defines the electrical and physical specifications of network media and connectors.

You are configuring a new network switch. In which layer of the OSI model does the switch operate when it forwards data packets based on their MAC addresses?

• Physical
• Data Link
• Network
• Transport

Answer explanation

The Data Link layer is responsible for error detection and addressing of frames on the network media. Switches use MAC addresses to determine the destination of a frame.

A user on your network complains that they cannot access certain websites while others load without issue. This situation most likely points to a problem at which layer of the OSI model?

• Application
• Presentation
• Session
• Transport

Answer explanation

The Transport layer is responsible for reliable data delivery between applications, and port issues can restrict access to specific services.

You are troubleshooting a network connection issue. You ping a device and receive several "Request timed out" messages. Which layer of the OSI model is most likely the cause of this problem?

• Physical
• Data Link
• Network
• Transport

Answer explanation

The Physical layer defines the physical characteristics that enable communication across the network. Ping utilizes ICMP messages at the Network layer, but a physical layer problem would prevent any communication.

While laying new network cables, a technician accidentally cuts a fiber optic cable. Which of the following tools would be MOST useful to repair the damage?

• Crimper
• Punch Down Tool
• Cable Tester
• Fusion Splicer

Answer explanation

A fusion splicer uses heat to permanently join two fiber optic cables.

You are designing a network for a small office with 20 workstations. Each department requires its own subnet to isolate traffic. Considering the need for future growth, which subnet mask would provide the most efficient use of IPv4 addresses while allowing for at least four subnets?

• /24
• /25
• /26
• /27

Answer explanation

A /26 subnet mask creates 64 usable IP addresses, allowing for efficient use of the limited space while providing enough addresses for four subnets and future growth.

You are configuring a new router. In which layer of the OSI model does the router operate when it forwards data packets based on their IP addresses?

• Physical
• Data Link
• Network
• Transport

Answer explanation

The Network layer is responsible for logical addressing and routing data packets across networks based on their IP addresses.