100-150 Standards and Concepts Practice Test 3 — 15 Questions

Question 1

A technician is troubleshooting a connectivity issue where a host can ping its default gateway but cannot reach a server on a different subnet. At which OSI layer is the routing decision being made?

Accepted Answer

Network Layer. Routing decisions are primarily handled at the Network Layer (Layer 3) of the OSI model. This layer is responsible for logical addressing and determining the best path for data to travel across interconnected networks. Understanding this layer is crucial for troubleshooting connectivity issues that extend beyond a local broadcast domain or a single physical segment.

Answer

Physical Layer

Answer

Data Link Layer

Answer

Transport Layer

Question 2

A company is deploying a new Voice over IP (VoIP) system and needs to minimize latency. Which transport protocol is most suitable for the real-time voice stream, and why?

Accepted Answer

UDP. UDP is the most suitable transport protocol for real-time VoIP voice streams because it is connectionless and has minimal overhead, avoiding the retransmission delays and head-of-line blocking that TCP introduces. Voice traffic prioritizes low latency and jitter over guaranteed delivery — a lost packet is better discarded than retransmitted late.

Answer

TCP

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ICMP

Answer

HTTP

Question 3

Refer to the exhibit. If a frame with a destination MAC address of 0055.4433.2211 arrives on interface FastEthernet 0/1, how will the switch handle the traffic?

Accepted Answer

Flood out Fa0/2. Switches use the MAC address table to make forwarding decisions. When a destination MAC is not found in the table, the switch performs an action known as unknown unicast flooding. It sends the frame out of every port in the same VLAN, except for the port on which the frame was originally received, to locate the destination device.

Answer

Forward to Fa0/2

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Drop the frame

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Update the table

Question 4

An administrator is running UTP cabling near heavy machinery and fluorescent lights. Users report intermittent connectivity and slow speeds. What is the most likely cause of this issue?

Accepted Answer

EMI. EMI (electromagnetic interference) is the most likely cause because heavy machinery and fluorescent lights emit electromagnetic fields that induce noise on unshielded twisted-pair (UTP) cabling. This noise corrupts signals, causing intermittent connectivity, retransmissions, and slow speeds. UTP lacks the shielding that STP or fiber provides against such interference.

Answer

Crosstalk

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Attenuation

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Reflection

Question 5

A startup wants to host a custom application in the cloud without managing the underlying operating system or hardware. Which THREE cloud service models or characteristics are relevant to this requirement?

Accepted Answer

PaaS. Cloud computing offers various service models depending on the level of management required by the customer. Platform as a Service (PaaS) is ideal for developers who want to focus on code rather than infrastructure. Understanding these models helps organizations choose the right balance between control and operational overhead for their specific workloads.

Answer

SaaS

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IaaS

Question 6

A network engineer is migrating a network to IPv6 to solve address exhaustion. Which feature of IPv6 eliminates the need for broadcasting to discover MAC addresses on a local link?

Accepted Answer

NDP. IPv6 Neighbor Discovery Protocol (NDP) replaces ARP and uses ICMPv6 messages (Neighbor Solicitation and Neighbor Advertisement) to resolve IPv6 addresses to MAC addresses on a local link. NDP eliminates the need for broadcasting because it uses multicast addresses (solicited-node multicast) to efficiently discover neighbors, making it the correct answer.

Answer

NAT

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ARP

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DHCPv6

Question 7

Refer to the exhibit. A company applies this JSON security policy to its edge firewall. What is the primary standard or concept being enforced by this configuration?

Accepted Answer

Confidentiality. This policy demonstrates the enforcement of secure web communication standards. By denying traffic on port 80 (HTTP) and allowing traffic on port 443 (HTTPS), the organization ensures that all web data is encrypted during transit. This is a fundamental security practice to protect sensitive information from being intercepted by unauthorized parties.

Answer

Data Integrity

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Availability

Answer

Physical Security

Question 8

As data moves down the OSI model from the Application layer to the Physical layer, what is the process called where each layer adds its own control information?

Accepted Answer

Encapsulation. Encapsulation is the fundamental process of wrapping data in a protocol header at each layer of the OSI model. This allows each layer to provide specific services, such as error checking or routing, without needing to understand the contents of the layers above it. It ensures that data is properly formatted for transmission across the network.

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De-encapsulation

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Segmentation

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Modulation

Question 9

A technician is examining a frame captured on a switch port and sees the destination MAC address field set to FF:FF:FF:FF:FF:FF. What is the purpose of this address in an Ethernet network?

Accepted Answer

It is a broadcast address that is delivered to all devices on the local network segment.. The all-FF MAC address is the Ethernet broadcast address. When a frame uses it as the destination, all devices in the same broadcast domain receive and process the frame. This is essential for address resolution and dynamic configuration protocols where the sender does not yet know the unicast MAC address of the intended recipient.

Answer

It is a loopback address that causes the frame to be sent back to the originating device.

Answer

It is a multicast address used to send frames to a specific group of devices that have joined a multicast group.

Answer

It is a special address that identifies the default gateway for the local subnet.

Question 10

A network administrator is configuring a switch port that connects to a server. The administrator wants to ensure that the port does not participate in Spanning Tree Protocol (STP) and immediately transitions to the forwarding state when the link comes up. Which feature should be configured on this port?

Accepted Answer

PortFast. PortFast is the correct feature because it allows an access port to skip the STP listening and learning states and go straight to forwarding, which is ideal for server connections. BPDU Guard, Root Guard, and Loop Guard are STP enhancement features that protect the topology but do not provide immediate forwarding.

Answer

Root Guard

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Loop Guard

Answer

BPDU Guard

Question 11

A network administrator is documenting the OSI model layers for a training manual. The administrator needs to identify which OSI layer is responsible for establishing, managing, and terminating sessions between applications on different hosts. Which OSI layer should be documented?

Accepted Answer

Session layer. The Session layer is specifically tasked with setting up, coordinating, and tearing down conversations between applications. It provides mechanisms for dialogue control and synchronization, which are distinct from the transport functions of Layer 4 or the data formatting of Layer 6. Documenting this layer accurately reflects its role in managing sessions between hosts.

Answer

Application layer

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Transport layer

Answer

Presentation layer

Question 12

A network technician is troubleshooting a connectivity issue. The technician suspects that a router is not forwarding packets correctly because the Time to Live (TTL) value in the IP header is being decremented to zero. Which field in the IPv4 header is responsible for this decrementing behavior and the subsequent discarding of the packet?

Accepted Answer

Time to Live (TTL) field. The TTL field is designed to limit the lifespan of a packet. Each router that forwards the packet decrements the TTL by one. If the TTL reaches zero, the router drops the packet and may send an ICMP Time Exceeded message. This prevents infinite loops and is the exact mechanism the technician suspects.

Answer

Header Checksum field

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Identification field

Answer

Protocol field

Question 13

A network engineer is configuring a new switch and needs to ensure that management traffic is isolated from user data traffic. The engineer decides to create a separate VLAN for management and assign an IP address to a switch virtual interface (SVI) on that VLAN. Which type of VLAN is being implemented?

Accepted Answer

Management VLAN. A management VLAN is dedicated to carrying administrative traffic, allowing network devices to be managed securely without mixing that traffic with user data. By creating such a VLAN and assigning an SVI, the engineer ensures that management access is isolated, which is a best practice for network security and segmentation.

Answer

Native VLAN

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Data VLAN

Answer

Voice VLAN

Question 14

A technician is documenting the OSI model for a training manual and needs to identify which layer is responsible for logical addressing and path determination between networks. Which OSI layer performs this function?

Accepted Answer

Network layer (Layer 3). The Network layer is responsible for logical addressing and routing, which are essential for moving data between different networks. Routers use IP addresses at this layer to determine the best path. The other layers handle different functions: Data Link uses MAC addresses, Transport ensures reliable delivery, and Session manages connections.

Answer

Session layer (Layer 5)

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Data Link layer (Layer 2)

Answer

Transport layer (Layer 4)

Question 15

A network administrator is reviewing the OSI model layer responsibilities. The administrator needs to identify which layer is responsible for establishing, managing, and terminating sessions between applications on different hosts. Which OSI layer performs this function?

Accepted Answer

Session layer. The Session layer is specifically tasked with setting up, maintaining, and ending sessions between applications. It provides dialog control and synchronization, which are essential for managing ongoing communications. The other layers have different primary functions: Transport ensures reliable data transfer, Presentation formats data, and Application provides services to users. Thus, the Session layer is the correct answer for session management.

Answer

Application layer

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Transport layer

Answer

Presentation layer