200-901 Network Fundamentals Practice Test 3 — 15 Questions

Question 1

A network engineer is troubleshooting connectivity issues and wants to verify the path that packets take from a source to a destination IP address. Which OSI layer is primarily responsible for packet forwarding and routing?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Layer 3 - Network. The Network layer (Layer 3) is responsible for packet forwarding and routing, using logical IP addresses to determine the best path from source to destination. Protocols like IP (IPv4/IPv6) and routing protocols (e.g., OSPF, BGP) operate at this layer to make forwarding decisions. The traceroute command is a common tool that leverages Layer 3 TTL (Time-to-Live) fields to map the path packets take.

Answer

Layer 4 - Transport

Answer

Layer 1 - Physical

Answer

Layer 2 - Data Link

Question 2

An application requires reliable, ordered delivery of data with flow control and retransmission of lost segments. Which transport layer protocol should the developer choose and what is a key characteristic of this protocol?

Accepted Answer

TCP; it uses a three-way handshake for connection establishment. TCP provides reliability, ordering, flow control, and retransmission. It uses a three-way handshake to establish a connection.

Answer

UDP; it provides ordered delivery through sequence numbers

Answer

TCP; it has lower overhead than UDP

Answer

UDP; it uses a three-way handshake for connection establishment

Question 3

A network administrator is configuring subnetting for a new branch office that requires 50 usable host addresses per subnet. The available network is 192.168.10.0/24. What subnet mask should be used to meet the requirement with minimal waste?

Accepted Answer

255.255.255.192 (/26). A /26 mask provides 62 usable hosts (2^(32-26)-2=62), which is the smallest subnet that supports 50 hosts.

Answer

255.255.255.128 (/25)

Answer

255.255.255.224 (/27)

Answer

255.255.255.240 (/28)

Question 4

A developer is designing a microservices architecture where services need to discover each other using DNS. The team wants to map a service name 'payment-service.example.com' to its IPv6 address. Which DNS record type should be used?

Accepted Answer

AAAA record. The AAAA record (Quad-A) is the correct DNS record type for mapping a hostname to an IPv6 address, as defined in RFC 3596. Since the requirement is specifically to resolve 'payment-service.example.com' to an IPv6 address, the AAAA record is the appropriate choice.

Answer

PTR record

Answer

A record

Answer

CNAME record

Question 5

A web application uses HTTPS to secure communications between client and server. What does HTTPS add on top of HTTP to provide encryption and authentication?

Accepted Answer

SSL/TLS. HTTPS uses TLS (Transport Layer Security) to encrypt HTTP traffic and verify server identity.

Answer

SSH

Answer

IPsec

Answer

VPN

Question 6

A network engineer is configuring a wireless network for a new office. To maximize performance and minimize interference, the engineer decides to use the 5 GHz band. Which of the following is a key advantage of 5 GHz over 2.4 GHz?

Accepted Answer

Less interference and more channels. 5 GHz offers more non-overlapping channels and less interference from common devices like microwaves and Bluetooth.

Answer

Better range through walls

Answer

Larger coverage area

Answer

Higher compatibility with older devices

Question 7

In Software-Defined Networking (SDN), the control plane is separated from the data plane. Which of the following best describes the function of the southbound API?

Accepted Answer

Interface between the controller and network devices. Southbound API is used by the SDN controller to communicate with network devices (e.g., switches, routers) to enforce forwarding rules.

Answer

Interface between applications and the controller

Answer

Communication between two controllers

Answer

Interface between the control plane and management plane

Question 8

A developer is troubleshooting an HTTP API call that returns a 404 status code. Which of the following is the most likely cause?

Accepted Answer

The requested URL endpoint does not exist. HTTP 404 indicates the requested resource could not be found on the server.

Answer

The server is unavailable due to maintenance

Answer

The server encountered an internal error

Answer

The client lacks proper authentication

Question 9

Which of the following is a private IPv4 address range as defined by RFC 1918?

Accepted Answer

192.168.0.0/16. RFC 1918 reserves the 192.168.0.0/16 block (192.168.0.0 – 192.168.255.255) as a private IPv4 address range, meaning these addresses are not routable on the public internet and are intended for use within private networks.

Answer

169.254.0.0/16

Answer

11.0.0.0/8

Answer

172.32.0.0/12

Question 10

A network administrator is configuring DNS for a corporate domain. An MX record is required to specify the mail server responsible for handling email. Which of the following is a correct example of an MX record?

Accepted Answer

example.com.  MX  10 mail.example.com.. An MX record specifies the mail server responsible for handling email for a domain, using the format: domain. MX priority mailserver. The priority value (10) indicates preference, with lower values being higher priority. This record directs email delivery to mail.example.com for the example.com domain.

Answer

mail.example.com.  A  192.0.2.1

Answer

example.com.  CNAME  mail.example.com.

Answer

example.com.  TXT  "v=spf1 include:_spf.google.com ~all"

Question 11

A network engineer is tasked with segmenting a large broadcast domain into smaller ones using VLANs. In the OSI model, at which layer does a VLAN operate?

Accepted Answer

Layer 2 - Data Link. VLANs operate at Layer 2 (Data Link) by tagging frames with VLAN IDs to separate broadcast domains.

Answer

Layer 4 - Transport

Answer

Layer 1 - Physical

Answer

Layer 3 - Network

Question 12

An application developer is using a protocol that does not require a connection setup and has minimal header overhead. Which transport protocol is being used?

Accepted Answer

UDP. UDP (User Datagram Protocol) is a connectionless transport-layer protocol that does not require a handshake (no SYN/SYN-ACK/ACK) and has minimal header overhead (only 8 bytes, compared to TCP's 20 bytes). This makes it ideal for applications like DNS queries, streaming media, or real-time communications where low latency is more critical than guaranteed delivery.

Answer

TCP

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HTTP

Answer

ICMP

Question 13

A network administrator is deploying a wireless network that supports the latest security standards and high throughput. Which TWO of the following are true regarding Wi-Fi 6 (802.11ax) compared to Wi-Fi 5 (802.11ac)?

Accepted Answer

Uses OFDMA for improved efficiency. Wi-Fi 6 (802.11ax) introduces Orthogonal Frequency Division Multiple Access (OFDMA), which subdivides a channel into smaller resource units (RUs) to serve multiple clients simultaneously, significantly improving efficiency in dense environments compared to Wi-Fi 5's OFDM that allocates the entire channel to a single user per transmission.

Answer

Uses only 20 MHz channels

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Maximum theoretical speed is lower than Wi-Fi 5

Answer

Operates only on the 5 GHz band

Question 14

A DevOps engineer is automating network configuration using REST APIs. The engineer needs to choose between NETCONF and OpenFlow as southbound protocols. Which TWO statements are correct?

Accepted Answer

OpenFlow allows the controller to install flow entries in switches. NETCONF uses XML and is used for configuration management, while OpenFlow pushes flow entries to switches.

Answer

NETCONF provides real-time packet forwarding control

Answer

Both protocols are used exclusively for northbound APIs

Answer

OpenFlow is primarily used for configuration management

Question 15

A developer is designing a system that requires high reliability and ordered data delivery. The developer chooses TCP. Which THREE features are provided by TCP?

Accepted Answer

Flow control using window size. TCP provides a three-way handshake, sequence numbering for ordering, and flow control.

Answer

Multicast support

Answer

Simple header with minimal overhead