200-901 Practice Test 46 — 15 Questions

Question 1

In an SDN architecture, which layer is responsible for making decisions about where traffic should be forwarded?

Accepted Answer

Control plane. In SDN architecture, the control plane is responsible for making forwarding decisions by maintaining the network topology and computing paths for traffic flows. It communicates these decisions to the data plane via southbound protocols like OpenFlow or NETCONF, ensuring that packets are forwarded according to the desired policies.

Answer

Data plane

Answer

Application plane

Answer

Management plane

Question 2

In the Ansible playbook snippet, what connection method is typically used for the ios_config module to communicate with the devices?

Accepted Answer

network_cli. The ios_config module is designed for Cisco IOS devices and requires a persistent network connection to send configuration commands. The network_cli connection method establishes an SSH session that remains open for the duration of the playbook task, allowing the module to send multiple CLI commands and handle prompts. This is the recommended connection method for ios_config because it supports privilege escalation and command responses needed for configuration changes.

Answer

local

Answer

netconf

Answer

httpapi

Question 3

A developer has a Docker container running a database. They need to inspect the database logs to debug a connection issue. Which command will show the logs in real-time?

Accepted Answer

docker logs -f my-db. The `docker logs -f` command attaches to the container's stdout/stderr streams and follows new output in real-time, which is exactly what is needed to debug a live connection issue. The `-f` flag (short for `--follow`) continuously prints log lines as they are written, allowing the developer to observe database connection attempts and errors as they occur.

Answer

docker exec my-db tail -f /var/log/mysql

Answer

docker logs --tail 100 my-db

Answer

docker logs my-db

Question 4

A developer wants to receive real-time notifications when a new message is posted in a Webex room. Which Webex API resource should they use?

Accepted Answer

Webhooks. Webhooks provide real-time HTTP callbacks triggered by events in Webex, such as a new message being posted. By registering a webhook on the 'messages' resource with the 'created' event, the developer's server receives a POST request immediately when a message is sent, eliminating the need for polling.

Answer

Memberships API

Answer

Rooms API

Answer

Messages API polling

Question 5

A developer is building a dashboard that displays the health status of network devices managed by Cisco ACI. The developer uses the ACI REST API to query the APIC (Application Policy Infrastructure Controller). The developer sends a GET request to https://apic-ip/api/class/fabricHealthInst.json returns a JSON object with health scores. The dashboard works for a small set of devices, but when scaled to 500 devices, the API responses become slower and sometimes time out. The developer needs to optimize the data retrieval to keep the dashboard responsive. Which approach should the developer use?

Accepted Answer

Use the ACI event subscription mechanism to receive health updates only when changes occur.. The ACI REST API supports an event subscription mechanism (e.g., WebSocket-based subscriptions) that pushes updates only when the health score of a device changes, rather than requiring the dashboard to poll the APIC repeatedly. This drastically reduces network overhead and server load, especially when scaling to 500 devices, as it eliminates the need for frequent full GET requests to /api/class/fabricHealthInst.json.

Answer

Break the request into multiple smaller requests, each fetching a subset of devices.

Answer

Add a query parameter to sort the results by health score to reduce processing time.

Answer

Switch from JavaScript to Python for the backend to handle larger responses more efficiently.

Question 6

A network engineer is designing a subnet that needs to support 30 usable hosts. Which subnet mask should be used?

Accepted Answer

255.255.255.224 (/27). (255.255.255.224, /27) provides 5 host bits, yielding 2^5 = 32 total addresses per subnet. Subtracting the network and broadcast addresses leaves exactly 30 usable hosts, meeting the requirement precisely.

Answer

255.255.255.240 (/28)

Answer

255.255.255.0 (/24)

Answer

255.255.255.192 (/26)

Question 7

Which TWO of the following are characteristics of UDP compared to TCP? (Select two.)

Accepted Answer

Lower overhead. Option D (Lower overhead) is correct because UDP has a fixed 8-byte header containing only source port, destination port, length, and checksum, with no sequence/acknowledgment fields, handshake, or connection state, whereas TCP's 20-byte (or larger) header and connection tracking add significant overhead. Option E (No flow control or congestion control) is correct because UDP simply sends datagrams without windowing, slow-start, or congestion-avoidance algorithms, so it does not throttle the sender based on receiver capacity or network congestion. Options A, B, and C are TCP characteristics: TCP provides ordered delivery via sequence numbers, reliable delivery with acknowledgments and retransmission, and connection-oriented communication via the three-way handshake, none of which UDP offers.

Answer

Ordered data delivery

Answer

Reliable delivery with retransmission

Answer

Connection-oriented communication

Question 8

Which Cisco platform provides a cloud-managed networking solution with a RESTful API that uses an API key in the X-Cisco-Meraki-API-Key header?

Accepted Answer

Cisco Meraki. The Meraki Dashboard API uses an API key in the X-Cisco-Meraki-API-Key header.

Answer

Cisco Webex

Answer

Cisco DNA Center

Answer

Cisco IOS XE

Question 9

A network automation engineer is using the Cisco DNA Center intent API to retrieve a list of network devices. Which API endpoint should be used?

Accepted Answer

GET /dna/intent/api/v1/network-device. The correct endpoint is GET /dna/intent/api/v1/network-device because the Cisco DNA Center intent API uses this path to retrieve a list of all network devices managed by the controller. The 'network-device' resource is specifically designed for device inventory operations, returning details such as hostname, IP address, platform ID, and software version. This aligns with the intent API's purpose of abstracting underlying complexities into business-relevant resources.

Answer

GET /dna/intent/api/v1/site

Answer

GET /dna/intent/api/v1/topology

Answer

GET /dna/intent/api/v1/issue

Question 10

A network automation script uses the Python ncclient library to modify a device configuration. Which NETCONF operation should be used to apply configuration changes?

Accepted Answer

. The operation is used to apply configuration changes to a device via NETCONF. It allows the client to modify the configuration data store on the server, which is exactly what the script intends to do.

Answer

<close-session>

Answer

<get-config>

Answer

<get>

Question 11

An HTTP/2 connection uses multiple concurrent streams over a single TCP connection. Which feature of HTTP/2 enables this?

Accepted Answer

Multiplexing. Multiplexing is the HTTP/2 feature that allows multiple concurrent streams to share a single TCP connection. This eliminates head-of-line blocking at the application layer by enabling the interleaving of frames from different streams, so a slow response on one stream does not block others.

Answer

Binary framing layer

Answer

Server push

Answer

Header compression (HPACK)

Question 12

Refer to the exhibit. Based on the YANG model snippet, what is the data type of the 'mask' leaf?

Accepted Answer

inet:ipv4-prefix-length. The 'mask' leaf is defined with the type 'inet:ipv4-prefix-length', which represents a decimal integer from 0 to 32 indicating the number of leading 1 bits in the subnet mask (e.g., 24 for /24). This is the correct data type for a prefix length in YANG models, not an IPv4 address or a generic string.

Answer

inet:ipv4-address

Answer

uint8

Answer

string

Question 13

Which THREE of the following are valid methods to automatically assign IP addresses to network hosts?

Accepted Answer

SLAAC. SLAAC (Stateless Address Autoconfiguration) is a valid method for automatically assigning IPv6 addresses to network hosts. It uses ICMPv6 Router Advertisement (RA) messages to provide a prefix, and the host generates its own interface identifier (often based on EUI-64 or privacy extensions) to form a complete IPv6 address without a central server.

Answer

Static assignment

Answer

DNS

Question 14

An engineer needs to identify which hosts are reachable in a 10.0.0.0/24 network using an automated script that does not require any credentials on the target devices. Which protocol is best suited for this task?

Accepted Answer

ICMP. ICMP (Internet Control Message Protocol) is the correct choice because it provides the Echo Request and Echo Reply messages (commonly used by the 'ping' command) that can determine host reachability without requiring any authentication or credentials on the target devices. This makes ICMP ideal for an automated script that needs to probe a 10.0.0.0/24 network for live hosts, as it operates at the network layer and only requires IP connectivity.

Answer

CDP

Answer

SNMP

Answer

ARP

Question 15

A developer is writing a Dockerfile for a Node.js application. They want to set a build-time variable for the application version that can be changed without modifying the Dockerfile. Which instruction should be used?

Accepted Answer

ARG. ARG allows passing build-time variables. ENV sets environment variables that persist in the container. CMD and RUN are not for variable definition.

Answer

RUN

Answer

ENV

Answer

CMD