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Automation and Programmability

200 questions

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Question 21Question →

An enterprise network relies on SNMPv3 polling at 15-minute intervals alongside manual SSH sessions to monitor and maintain 400 access switches. During an incident investigation, engineers discover that out-of-band configuration changes occurred and went undetected for several hours between polling cycles. How does migrating to an API-driven centralized controller framework fundamentally alter this operational paradigm to address configuration drift?

Show answer & explanation

Answer: It introduces model-driven telemetry and centralized state enforcement to continuously monitor, detect, and automatically reconcile unauthorized configuration drift in real time.

Answer

Migrating to an API-driven centralized controller framework introduces model-driven telemetry and centralized state enforcement to continuously monitor, detect, and automatically reconcile unauthorized configuration drift in real time.
Centralized controller-based network management shifts network operations from manual, pull-based polling (SNMP) to programmatic, push-based model-driven telemetry and centralized intent enforcement. Controllers maintain the intended network state as a single source of truth, enabling immediate detection and automated remediation of unauthorized configuration drift.

Step-by-Step Solution

1
Identify the operational limitation of traditional management described in the scenario.
Periodic SNMP polling (pull-based) and manual CLI management create visibility gaps between polling intervals, allowing unauthorized configuration drift to go unnoticed.
Traditional management relies on discrete polling schedules rather than continuous real-time state streaming.
2
Evaluate how modern automation and controller-based frameworks handle change management.
Centralized controllers use programmatic REST APIs and streaming telemetry (push-based) to maintain a single source of truth and detect drift as soon as it occurs.
Declarative configuration models define the intended state, enabling automated state reconciliation when device state diverges.
3
Select the option that accurately describes this operational shift.
Model-driven telemetry and centralized state enforcement solve visibility gaps and enable immediate drift remediation.
This contrasts directly with pull-based SNMP polling and manual CLI management.

Key Concept

Impact of Automation on Network Management: Real-time telemetry, centralized configuration state enforcement, and configuration drift reduction.
Question 22Question →

A network engineer is reviewing system performance and network health metrics within Cisco DNA Center Assurance. To provide real-time visibility and health scores without the high processing overhead of traditional polling, how does Cisco DNA Center gather continuous operational telemetry from managed switches?

Show answer & explanation

Answer: Managed switches use model-based streaming telemetry over protocols such as NETCONF or gRPC to continuously push operational state metrics to Cisco DNA Center.

Answer

Managed switches use model-based streaming telemetry over protocols such as NETCONF or gRPC to continuously push operational state metrics to Cisco DNA Center.
Cisco DNA Center Assurance leverages model-based streaming telemetry to achieve real-time health monitoring. Network devices continuously push structured operational state data to Cisco DNA Center using protocols such as NETCONF or gRPC, eliminating the CPU burden associated with frequent SNMP polling.

Step-by-Step Solution

1
Identify the data collection requirement in Cisco DNA Center Assurance.
Assurance requires real-time, granular metrics to calculate overall Health Scores for network devices, clients, and applications.
Traditional SNMP polling introduces bandwidth and CPU overhead, making high-frequency monitoring impractical.
2
Analyze how Cisco DNA Center collects continuous telemetry from managed devices.
Devices are configured to push subscription data using YANG models via NETCONF or gRPC (streaming telemetry).
Push-based streaming telemetry delivers continuous, structured operational data in near real-time directly to the controller.

Key Concept

Cisco DNA Center Telemetry and Health Assurance
Question 23Question →

A network operations team replaces traditional periodic SNMP polling with API-driven streaming telemetry push notifications across enterprise switches. Which operational advantage does this architectural shift directly provide to network management?

Show answer & explanation

Answer: It continuously streams structured data from network devices in near real-time upon state changes, reducing monitoring latency and CPU overhead compared to periodic polling.

Answer

Streaming telemetry continuously pushes structured data from network devices in near real-time upon state changes, reducing monitoring latency and CPU overhead compared to periodic SNMP polling.
Transitioning from periodic SNMP polling to API-driven streaming telemetry allows network devices to push operational statistics in near real-time whenever state changes occur or on structured subscription intervals. This significantly reduces latency, optimizes network bandwidth, and lowers CPU utilization on monitored devices.

Step-by-Step Solution

1
Analyze traditional SNMP polling mechanics.
Traditional network management uses polling where a central management station periodically queries network devices using SNMP GET requests, creating latency and high CPU overhead on managed devices.
Understanding the limitations of traditional polling sets the baseline for automation impact.
2
Evaluate the architectural shift to model-driven streaming telemetry.
Streaming telemetry establishes a publish-subscribe model where network devices push structured telemetry data continuously or when state changes occur.
This shift allows network managers to receive immediate operational visibility without polling overhead.
3
Identify the primary operational benefit.
Near real-time data availability, lower CPU usage on network devices, and optimal bandwidth usage form the core impact of streaming telemetry on enterprise network management.
Directly matches the target subtopic requirement.

Key Concept

Impact of Streaming Telemetry vs Traditional Polling on Network Management
Question 24Question →

A network engineer is deploying a factory-default Cisco Catalyst switch at a remote site where no local DHCP server or custom DHCP options exist. The switch serial number and Smart Account details have already been registered in the organization's Cisco Catalyst Center (Cisco DNA Center) portal. The switch is powered on and receives outbound internet connectivity. Which mechanism enables the switch to automatically discover its controller management IP address for zero-touch Day-0 Network Plug and Play (PnP) onboarding?

Show answer & explanation

Answer: The switch queries the Cisco PnP Connect cloud redirection service over HTTPS using its serial number and platform identity.

Answer

The switch queries the Cisco PnP Connect cloud redirection service over HTTPS using its serial number and platform identity.
When a factory-default Cisco Catalyst switch boots up without receiving DHCP Option 43 or discovering a local DNS server entry for 'pnpserver', its built-in PnP agent contacts the Cisco Plug and Play Connect cloud service (devicehelper.cisco.com) via secure HTTPS. PnP Connect checks the switch's serial number against the customer's Smart Account and redirects the device to its registered Cisco Catalyst Center (Cisco DNA Center) management IP address.

Step-by-Step Solution

1
Identify the Day-0 Network Plug and Play (PnP) discovery order for unconfigured Cisco Catalyst switches.
The default PnP agent discovery sequence attempts DHCP Option 43 first, followed by local DNS lookup (pnpserver.domain), and finally Cisco PnP Connect cloud redirection.
Because DHCP server options and local DNS are absent in this scenario, the switch falls back to the internet-based cloud redirection service.
2
Analyze how Cisco PnP Connect functions for cloud redirection.
The switch initiates a secure HTTPS connection to Cisco's cloud portal (devicehelper.cisco.com) and presents its hardware serial number and PID.
Cisco Smart Software Manager matches the device serial number to the organization's Smart Account and returns the IP/FQDN of the assigned Cisco Catalyst Center instance.
3
Evaluate the alternative options against PnP architectural roles.
Layer 2 CDP, embedded Ansible agents, and HTTP POST gateway redirects are invalid PnP controller discovery mechanisms.
PnP is a controller-led, agent-initiated protocol specifically engineered for zero-touch provisioning over IP networks.

Key Concept

Cisco DNA Center / Catalyst Center Network Plug and Play (PnP) Day-0 Cloud Redirection
Question 25Question →

An enterprise network engineering team is transitioning from traditional per-device CLI configuration management to a centralized, API-driven network automation architecture. Which TWO statements accurately describe the operational impacts of adopting this network automation framework? (Select TWO.)

Select all that apply

Show answer & explanation

Answer: Configuration drift is significantly reduced by defining baseline states in a centralized repository and programmatically enforcing compliance across devices.; Network changes can be pre-tested in CI/CD pipelines and deployed consistently across multiple nodes using structured data models and templates.

Answer

The operational impacts of adopting a network automation framework include significantly reducing configuration drift by enforcing baseline states from a single source of truth, and enabling consistent, pre-validated change deployment across multiple devices using structured templates and data models.
Transitioning to API-driven automation replaces error-prone, per-device CLI commands with centralized configuration management. By maintaining a single source of truth, automated systems detect and remediate configuration drift automatically. Additionally, changes can be programmatically tested in software pipelines and deployed uniformly across numerous switches and routers using standardized templates.

Step-by-Step Solution

1
Analyze how network automation alters configuration management and compliance enforcement.
Centralized repositories store intended network state, allowing automated scripts or controllers to detect and fix out-of-band manual edits (reducing configuration drift).
Traditional CLI management suffers from human error and manual variation across network devices over time.
2
Evaluate the mechanism for provisioning changes in an automated environment.
Using structured data models (e.g., YANG/JSON) alongside templating engines allows bulk, identical updates to be validated prior to execution.
Automated pipelines minimize deployment errors by standardizing how configuration variables are injected into device templates.
3
Differentiate management plane operations from physical underlay connectivity and control plane functions.
Management plane automation does not bypass the necessity of physical underlay IP routing or eliminate local control plane routing protocols.
Automation alters how network devices are configured and monitored, but does not remove core infrastructure networking requirements.

Key Concept

Impact of Automation on Network Management
Question 26Question →

An enterprise network operations team is executing a digital transformation project to migrate a legacy campus environment using per-device CLI management and distributed control protocols (OSPF and STP) to a software-defined controller-based network using Cisco DNA Center. During the architectural review, engineers evaluate how device provisioning, control plane mechanics, and API interactions differ between traditional distributed models and centralized controller-based fabrics. Which two of the following statements accurately describe key operational and architectural distinctions between traditional and controller-based networking?

Select all that apply

Show answer & explanation

Answer: Control plane policy definition is centralized at the controller, which abstracts physical topology details and uses Southbound APIs to push programmatic configurations across network devices.; Northbound REST APIs allow external management applications and automation scripts to programmatically interact with the SDN controller rather than directly communicating with individual network switches.

Answer

The two correct statements state that control plane policy definition is centralized at the controller using Southbound APIs to manage data-plane devices, and that Northbound REST APIs allow applications to programmatically interact with the controller rather than individual switches.
In controller-based networking, the centralized controller decouples intent and policy management from individual physical hardware. It relies on Southbound APIs (e.g., NETCONF, RESTCONF, OpenFlow) to program data-plane network devices and exposes Northbound REST APIs to enable higher-level applications and scripts to automate network-wide operations without direct CLI manipulation of individual nodes.

Step-by-Step Solution

1
Analyze control plane separation and API roles in SDN architectures.
Centralized SDN controllers abstract management and control plane functions, using Southbound APIs (e.g., NETCONF/RESTCONF) to communicate down to physical infrastructure and Northbound APIs (RESTful HTTP) to communicate up to applications.
This establishes the fundamental architectural boundary between Northbound and Southbound interfaces in controller-based networking.
2
Evaluate the HTTP verb mapping for telemetry retrieval.
Retrieving data uses the HTTP GET method, while HTTP POST creates resources.
Mapping HTTP POST to state retrieval represents a fundamental CRUD misinterpretation in RESTful interface operations.
3
Evaluate switch management requirements and agent architectural models.
Cisco controller architectures utilize agentless Southbound management protocols rather than installing local software agents on switch operating systems.
Differentiating agent-based configuration models (e.g., Puppet/Chef) from standard SDN agentless protocol interfaces is critical when comparing traditional vs SDN environments.

Key Concept

Centralized SDN Architectures, Control/Data Plane Separation, and Northbound vs Southbound APIs
Question 27Question →

A network administrator is deploying brand-new, unconfigured enterprise switches using Cisco DNA Center Network Plug and Play (PnP). Which two mechanisms can an unconfigured switch use to automatically discover the IP address of the Cisco DNA Center controller? (Select two.)

Select all that apply

Show answer & explanation

Answer: DHCP Option 43 provided by the local DHCP server; DNS query resolution for the hostname pnpserver.domain_name

Answer

The correct mechanisms are DHCP Option 43 provided by the local DHCP server and DNS query resolution for the hostname pnpserver.domain_name.
Cisco DNA Center Network Plug and Play (PnP) enables zero-touch provisioning of new network devices. An unconfigured switch booted out-of-the-box uses its PnP agent to discover the controller IP address via DHCP Option 43 or by looking up the well-known DNS name 'pnpserver'.

Step-by-Step Solution

1
Identify the primary mechanism used by Cisco DNA Center Network Plug and Play (PnP) for Day-0 device onboarding.
When powered on, an unconfigured switch acquires IP configuration via DHCP.
DHCP Option 43 specifies the controller IP address directly to the PnP agent on the switch.
2
Identify the fallback discovery mechanism when DHCP Option 43 is absent.
The switch constructs a DNS request for 'pnpserver.<domain-name>'.
If DNS resolves 'pnpserver' to the IP address of Cisco DNA Center, the switch initiates contact automatically.

Key Concept

Cisco DNA Center Network Plug and Play (PnP) Discovery Methods
Question 28Question →

A network administrator is preparing to update software across a group of Cisco Catalyst access switches using Cisco DNA Center Software Image Management (SWIM). Which two actions or prerequisites are required in Cisco DNA Center before the new software image can be successfully activated on the target devices? (Select two.)

Select all that apply

Show answer & explanation

Answer: Tag the imported software image as a Golden Image for the targeted device model and role.; Run pre-check procedures to validate system readiness, such as checking available flash memory and device health.

Answer

Tagging the imported software image as a Golden Image for the targeted device model and running pre-check procedures to validate system readiness.
In Cisco DNA Center SWIM, software deployment requires marking an image as Golden for the target device family and running pre-checks to confirm device readiness and storage capacity before activating the image.

Step-by-Step Solution

1
Import and designate the software image in Cisco DNA Center
The image is imported into the image repository and marked as 'Golden' for the specific device family.
SWIM requires an image to be tagged as Golden before it can mark devices as non-compliant and schedule software updates.
2
Run pre-checks and readiness checks
Cisco DNA Center verifies available storage space, device health, and network connectivity.
Pre-upgrade checks prevent installation failures caused by insufficient flash space or existing device errors.

Key Concept

Cisco DNA Center Software Image Management (SWIM) Workflow
Question 29Question →

A network administrator is setting up a discovery job in Cisco DNA Center to scan an enterprise IPv4 subnet and onboard several existing Catalyst switches into the controller inventory. Which TWO credentials or protocol parameters must be configured within the Cisco DNA Center discovery settings to successfully discover the devices and transition them into a managed state?

Select all that apply

Show answer & explanation

Answer: SNMP read/write community strings or v3 credentials for SNMP-based attribute polling; CLI credentials (SSH or Telnet) to enable direct command-line execution and configuration parsing

Answer

To successfully discover and bring network devices into a fully managed state within Cisco DNA Center, the discovery profile requires SNMP credentials (v2c community strings or v3 user details) and CLI credentials (SSH/Telnet usernames and passwords/enable passwords).
For Cisco DNA Center to discover devices and transition them from 'Discovered' to 'Managed' state, the discovery job profile must contain valid SNMP parameters (for initial MIB polling and device profiling) and valid CLI credentials (SSH/Telnet credentials for deep configuration inspection and command execution).

Step-by-Step Solution

1
Identify the primary protocols Cisco DNA Center uses to discover network inventory.
Cisco DNA Center relies on SNMP queries to identify device platforms, serial numbers, and system object IDs during network discovery sweeps.
SNMP provides standardized, lightweight MIB access for initial device identification.
2
Determine how Cisco DNA Center gathers detailed configuration state and performs device management.
Cisco DNA Center logs into the switch via SSH/Telnet using configured CLI credentials to parse running configurations and push provisioning changes.
CLI access allows the controller to read complete feature configurations and issue commands directly.
3
Evaluate why alternative options are incorrect for Cisco DNA Center discovery.
Local web REST API tokens, TACACS+ shared secret keys for discovery handshakes, and local Ansible agent daemons are not part of the standard Cisco DNA Center discovery profile requirements.
Cisco DNA Center utilizes agentless southbound protocols (SNMP, SSH, NETCONF) rather than local switch agent daemons or web API tokens.

Key Concept

Cisco DNA Center Network Discovery and Device Management Protocols
Question 30Question →

A network architect is comparing the convergence and operational behavior of a legacy campus environment running distributed routing protocols against a controller-based Software-Defined Networking (SDN) fabric. Following an unexpected link failure within the core infrastructure, which statement correctly contrasts how control plane state and data plane forwarding updates are processed in the controller-based architecture versus the traditional distributed network model?

Show answer & explanation

Answer: The centralized controller recalculates the network topology and updates device forwarding tables via Southbound interface protocols, whereas traditional routers individually compute routing algorithms locally to update their own forwarding tables.

Answer

The centralized controller recalculates the network topology and updates device forwarding tables via Southbound interface protocols, whereas traditional routers individually compute routing algorithms locally to update their own forwarding tables.
The correct answer accurately describes the fundamental distinction: controller-based networks centralize control plane logic within an SDN controller that programs data plane switches via Southbound APIs, whereas traditional networks use a distributed control plane where each node independently computes paths and populates its local forwarding table.

Step-by-Step Solution

1
Analyze the control plane architecture of traditional networking.
In traditional networking, each router and switch maintains a distributed control plane. Devices independently run routing protocols (e.g., OSPF, EIGRP), compute shortest paths locally, and populate their own Routing Information Base (RIB) and Forwarding Information Base (FIB).
Understanding distributed control plane mechanics is essential for contrasting traditional architectures with SDN.
2
Analyze the control plane architecture of controller-based networking (SDN).
In controller-based networking, the control plane functions are centralized into an SDN controller (e.g., Cisco DNA Center / SD-Access). The controller possesses a global view of the network, computes paths centrally, and uses Southbound APIs (e.g., NETCONF, RESTCONF, gRPC, OpenFlow) to program the data plane (FIB) of individual network nodes.
Centralized control plane separation and Southbound API programming are the defining architectural characteristics of SDN.
3
Compare response to link failures and topology state updates in both architectures.
During a topology change, an SDN controller updates its central topology map and pushes updated forwarding tables down to devices via Southbound APIs. In contrast, traditional routers flood Link-State Advertisements (LSAs) or update messages and individually re-run local SPF calculations.
This direct comparison isolates the core functional difference during network failure events.

Key Concept

Centralized vs. Distributed Control Plane Architecture and Southbound API Integration
Estimated Time:2m 0s
Question 31Question →

A network automation engineer is designing Python scripts to interact with Cisco DNA Center and RESTCONF API endpoints for network configuration management. Which two statements accurately describe the characteristics and operational mechanics of HTTP verbs, headers, and data formats used in REST-based APIs? (Select two.)

Select all that apply

Show answer & explanation

Answer: HTTP PUT requests are idempotent and replace the specified resource entirely with the request payload, whereas HTTP PATCH requests apply partial modifications to an existing resource.; The Content-Type HTTP header informs the server of the data format contained in the request body, while the Accept header specifies the data format expected in the response.

Answer

The two correct characteristics of REST-based APIs are: (1) HTTP PUT requests are idempotent and perform a full resource replacement while HTTP PATCH applies partial updates, and (2) the Content-Type header defines the request payload format while the Accept header defines the expected response format.
The statement regarding HTTP PUT being idempotent and replacing the resource fully while HTTP PATCH applies partial updates is correct, as PUT replaces the target entity entirely and repeating the request results in the same server state, whereas PATCH modifies only the specified attributes. Additionally, the statement regarding Content-Type specifying the request payload format and Accept specifying the desired response format is correct, as Content-Type tells the server how to parse the incoming payload while Accept expresses client preference for the returned payload encoding.

Step-by-Step Solution

1
Analyze HTTP verb behaviors (CRUD mapping and idempotency)
PUT maps to Update/Replace and is idempotent because re-sending the same payload produces the exact same state. PATCH maps to partial modification. POST maps to Create (or general execution) and is non-idempotent because multiple identical calls create multiple items.
Understanding idempotency and CRUD mapping prevents unintended duplicate resource creation in network automation scripts.
2
Evaluate HTTP header functions for payload data types
The Content-Type header informs the receiver how to parse the incoming request body (e.g., application/json), while the Accept header negotiates the response payload format desired by the client.
API gateways and controllers rely on these headers to decode request payloads and serialize response payloads correctly.
3
Verify JSON data structure syntax
In JSON syntax, `{}` defines an object comprising key-value pairs, whereas `[]` defines an array of values.
Parsing API responses or crafting valid configuration payloads requires correct identification of objects versus arrays.

Key Concept

Characteristics of REST-Based APIs (HTTP Verbs, Idempotency, Headers, and Data Formats)
Question 32Question →

Match each HTTP verb commonly used in REST-based network automation APIs to its corresponding CRUD operation.

Click a left item, then click its matching right item

Items

GET
POST
PUT
DELETE

Matches

Show answer & explanation

Answer

GET maps to Read, POST maps to Create, PUT maps to Update / Replace, and DELETE maps to Delete.
In REST-based APIs, standard HTTP verbs correspond directly to CRUD operations: GET retrieves information (Read), POST creates new resources (Create), PUT updates or overwrites existing resources (Update), and DELETE removes resources (Delete).

Step-by-Step Solution

1
Identify the primary function of each HTTP request method in RESTful web services.
GET retrieves data; POST creates data; PUT updates/replaces data; DELETE removes data.
REST architecture standardizes data operations by mapping HTTP methods directly to database operations.
2
Match each HTTP verb to its corresponding acronym component in CRUD (Create, Read, Update, Delete).
POST = Create, GET = Read, PUT = Update, DELETE = Delete.
This 1-to-1 mapping is a fundamental characteristic of REST-based API design.

Key Concept

Mapping HTTP Verbs to CRUD Operations in RESTful APIs
Question 33Question →

A network automation engineer is building Python scripts to manage network infrastructure via Cisco DNA Center and RESTCONF API endpoints. Match each HTTP request component or operation to its correct RESTful behavior.

Click a left item, then click its matching right item

Items

HTTP POST request targeting a collection URI
HTTP PUT request targeting a specific interface resource
HTTP PATCH request targeting a specific interface resource
Accept header set to application/yang-data+json

Matches

Show answer & explanation

Answer

HTTP POST maps to creating a resource or triggering an async task. HTTP PUT maps to replacing the complete representation of a target resource. HTTP PATCH maps to applying partial modifications to a resource. The Accept header specifies the client's expected response format.
Each item matches its fundamental REST API operational characteristic: HTTP POST creates resources/tasks, HTTP PUT replaces the full representation, HTTP PATCH applies partial updates, and the Accept header defines the expected format of response data.

Step-by-Step Solution

1
Identify the operation performed by HTTP POST in REST APIs.
POST creates child resources or invokes task processing, returning HTTP status codes such as 201 Created or 202 Accepted.
Demonstrate knowledge of HTTP verb to CRUD mapping.
2
Differentiate between HTTP PUT and HTTP PATCH operations.
PUT replaces the complete resource state (omitted fields revert to defaults), whereas PATCH modifies only specified fields (omitted fields remain unchanged).
Distinguish full resource replacement from partial modification in RESTful APIs.
3
Determine the role of the HTTP Accept header.
The Accept header negotiates response encoding (e.g., application/yang-data+json) sent from the server back to the client.
Understand HTTP headers used in RESTCONF and RESTful communications.

Key Concept

Characteristics of REST-Based APIs (CRUD, HTTP Verbs, Data Formats)
Question 34Question →

A network engineer initiates a Discovery job in Cisco DNA Center using an IP address range to add existing enterprise switches into the controller's inventory. After establishing initial reachability and credential authentication, Cisco DNA Center collects neighbor data from Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP). How does Cisco DNA Center utilize this neighbor protocol data during the management workflow?

Show answer & explanation

Answer: To map link connections and dynamically build the physical network topology view

Answer

Cisco DNA Center uses CDP and LLDP neighbor data to map physical inter-device connections and construct the network topology view.
During the discovery phase, Cisco DNA Center queries discovered network devices via SNMP and CLI/SSH to retrieve their CDP and LLDP neighbor tables. By stitching together the neighbor relationships reported by each device, Cisco DNA Center automatically calculates link adjacencies and constructs the complete physical network topology map.

Step-by-Step Solution

1
Analyze the role of Layer 2 discovery protocols (CDP/LLDP) in controller-based networking.
CDP and LLDP allow network devices to advertise identity, capabilities, and connected local/remote port pairs to directly connected neighbors.
Understanding what data Layer 2 discovery protocols provide helps identify how a central controller consumes this information.
2
Evaluate how Cisco DNA Center uses collected discovery data during inventory creation.
Once SNMP/SSH access is validated, Cisco DNA Center reads the neighbor tables of discovered devices to calculate adjacencies.
This automated parsing eliminates manual topology mapping and builds a dynamic, interactive map of the network infrastructure.

Key Concept

Cisco DNA Center Topology Mapping via Discovery Protocols
Question 35Question →

A network architect is analyzing the architectural differences during a migration from a legacy campus network to a controller-based software-defined networking (SDN) model. In the legacy environment, switches operate using a traditional distributed control plane, whereas the new architecture utilizes a centralized SDN controller. Which statement accurately describes the fundamental shift in control plane processing and forwarding table management when transitioning to the controller-based model?

Show answer & explanation

Answer: The centralized controller assumes responsibility for control plane intelligence and uses Southbound APIs to program forwarding tables directly onto hardware devices, while data plane traffic continues to be forwarded locally by the physical switches.

Answer

The centralized controller assumes responsibility for control plane intelligence and uses Southbound APIs to program forwarding tables directly onto hardware devices, while data plane traffic continues to be forwarded locally by the physical switches.
In traditional networking, each network node maintains both its own control plane (calculating topologies and paths) and data plane (forwarding frames/packets). In controller-based networking, the control plane is abstracted and centralized within the controller. The controller uses Southbound APIs to push compiled forwarding policies down to physical network devices, allowing the switches to execute data plane packet forwarding at hardware wire speed without having to compute topology calculations independently.

Step-by-Step Solution

1
Identify the traditional network control plane characteristics
Traditional network switches run distributed control plane protocols (e.g., OSPF, EIGRP, STP) locally on every device to independently build routing and MAC address tables.
Understanding legacy architecture establishes the baseline distributed control plane model.
2
Identify the controller-based (SDN) network characteristics
SDN decouples the control plane from physical devices and centralizes it into a software controller.
Centralization enables global network visibility, automated policy enforcement, and programmatic control.
3
Differentiate interface roles (Northbound vs Southbound APIs) and plane separation
The controller uses Southbound interfaces (APIs/protocols like OpenFlow, NETCONF, RESTCONF) to communicate down to networking hardware, programming the local data planes for distributed line-rate forwarding. Northbound APIs interact upwards with applications and management software.
This confirms that data plane forwarding remains local on physical switch ASICs while control plane logic is offloaded to the controller.

Key Concept

Separation of Control Plane and Data Plane in SDN vs Traditional Distributed Control Planes
Estimated Time:1m 30s
Question 36Question →

A network administrator sends an HTTP request to a Cisco RESTCONF API endpoint attempting to update only the description of interface GigabitEthernet0/1. The API responds with an HTTP status code indicating success (204 No Content). However, a subsequent GET request reveals that the interface's previously configured IP address and administrative status were removed and reset to default values. Which HTTP verb was executed to cause this full resource replacement, and which HTTP verb should have been used instead to perform a partial update that preserves the existing unmentioned attributes?

Show answer & explanation

Answer: The administrator used HTTP PUT, which replaces the target resource entirely with the request payload; HTTP PATCH should have been used for a partial update.

Answer

The administrator executed an HTTP PUT request, which performs a complete resource replacement, and should have used an HTTP PATCH request to perform a partial update.
In REST-based network automation APIs (such as RESTCONF and Cisco DNA Center APIs), HTTP PUT maps to the update/replace CRUD operation. Executing a PUT request replaces the entire target resource with the payload supplied in the body. If optional fields (such as IP address or administrative status) are omitted from the PUT payload, the API server replaces the existing configuration object with the new partial payload, clearing or defaulting all omitted attributes. Conversely, HTTP PATCH is designed specifically for partial updates; it modifies only the fields present in the request body while leaving all unmentioned configuration parameters unchanged.

Step-by-Step Solution

1
Analyze the observed behavior after the API request execution.
The API returned a 204 No Content success code, but unmentioned fields (IP address and admin status) were deleted/reset.
Understanding resource mutation semantics helps identify which verb replaces the entire schema tree vs updating individual leaves.
2
Differentiate between HTTP PUT and HTTP PATCH REST operations.
HTTP PUT operates as a full resource replacement (Create/Replace). Any omitted JSON/XML elements in a PUT payload are assumed to be set to null or default values. HTTP PATCH operates as a partial update (Modify), altering only key-value pairs present in the request body.
REST API definitions mandate that PUT replaces the target entity in its entirety, whereas PATCH applies partial modifications to a resource.
3
Select the correct combination matching the scenario requirement.
The initial request was HTTP PUT (causing full replacement), and the correct verb for partial update is HTTP PATCH.
Using PATCH preserves all non-targeted interface parameters while modifying only the description field.

Key Concept

RESTful HTTP Verbs and CRUD Operation Semantics (PUT vs PATCH)
Question 37Question →

A network engineer completes an IP subnet discovery scan in Cisco DNA Center, successfully importing a newly installed Catalyst switch into the inventory. The device currently displays a status of 'Unassigned' in the global inventory view. The engineer must now apply centralized network settings—including global NTP servers, AAA settings, Syslog destinations, and day-N CLI templates—to this switch. Which operational step must be performed within Cisco DNA Center to push these configurations to the device?

Show answer & explanation

Answer: Assign the switch to a site within the network hierarchy and run the Provision workflow

Answer

Assign the switch to a site within the network hierarchy and run the Provision workflow.
In Cisco DNA Center, network settings (such as DNS, NTP, AAA, Syslog) and configuration templates are bound to nodes in the physical network hierarchy. When a device is discovered, it enters the inventory in an 'Unassigned' state. To push configurations, the administrator must assign the switch to its respective site (Area/Building/Floor) and launch the Provision workflow, which applies all inherited site settings and templates to the device.

Step-by-Step Solution

1
Identify current state in Cisco DNA Center Inventory
The device is discovered but marked as 'Unassigned', meaning no site-level policies or templates apply to it yet.
Cisco DNA Center organizes policies and network settings hierarchically by site (Global > Area > Building > Floor).
2
Associate device with the Network Hierarchy
The switch inherits global and site-specific network settings (NTP, Syslog, AAA, DNS, Telemetry).
Site assignment is a prerequisite for provisioning settings and configuration templates.
3
Execute the Provision workflow
Cisco DNA Center pushes the inherited site settings and assigned CLI templates to the switch and updates its status to 'Provisioned'.
The Provision task compiles the intent and deploys configuration changes directly to the target network element.

Key Concept

Cisco DNA Center Site Assignment and Provisioning Workflow
Question 38Question →

A network administrator needs to perform a Software Image Management (SWIM) upgrade on enterprise switches using Cisco DNA Center. What is the correct chronological sequence of steps required to complete this software deployment workflow from start to finish?

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence for a Cisco DNA Center Software Image Management (SWIM) upgrade is: 1) Import the software image into the Image Repository, 2) Mark the image as Golden for the device family, 3) Run pre-checks on target devices, 4) Distribute the software image to the switch storage, and 5) Activate the software image to reboot the switch into the new version.
The correct workflow in Cisco DNA Center Software Image Management (SWIM) begins with importing the software binary into the repository, followed by marking it as a Golden Image for the target device family to set compliance standards. Next, pre-checks are run to ensure devices have sufficient storage space and satisfy health conditions. Once verified, the image is distributed (staged) to the target storage, and finally activated to reboot the switch into the updated software version.

Step-by-Step Solution

1
Import the software image into Cisco DNA Center.
The binary image file is indexed within Cisco DNA Center's Image Repository.
Cisco DNA Center requires image files to reside in its repository before they can be evaluated or assigned.
2
Tag the image as Golden for the target hardware platform.
Devices running older or non-matching code are flagged as non-compliant.
Golden image tagging establishes the compliant baseline version within the network hierarchy.
3
Perform readiness pre-checks on candidate switches.
Flash storage, running configuration integrity, and hardware compatibility are verified.
Pre-checks prevent distribution or activation failures due to insufficient memory or incompatible settings.
4
Initiate image distribution.
The software file is copied across the network onto the switch flash storage.
Staging the file beforehand allows distribution to occur prior to a scheduled maintenance window.
5
Execute image activation.
Boot configuration is updated and the switch reboots using the new software image.
Activation completes the upgrade cycle by rebooting the hardware to run the distributed binary.

Key Concept

Cisco DNA Center Software Image Management (SWIM) Workflow
Estimated Time:1m 30s
Question 39Question →

Which two statements accurately describe key characteristics of JSON data formatting in REST-based network API interactions? (Choose two.)

Select all that apply

Show answer & explanation

Answer: Key names in JSON objects must be formatted as strings enclosed in double quotes.; Square brackets [] are used to declare ordered arrays or lists of data values.

Answer

The correct characteristics of JSON formatting are that key names must be strings enclosed in double quotes and square brackets are used to declare ordered arrays of data.
JSON uses specific syntax rules: key names must be double-quoted strings, and ordered arrays are contained within square brackets []. These characteristics make JSON lightweight and human-readable for network automation APIs.

Step-by-Step Solution

1
Identify the basic structural syntax of JSON payloads.
JSON represents objects using key-value pairs wrapped in curly braces {}, where keys are strings surrounded by double quotes.
This syntax differentiates JSON from other data formats like YAML or unquoted key structures.
2
Determine how collections of items are formatted in JSON.
Ordered lists or sequences of values are declared using square brackets [].
Square brackets indicate array types within a JSON structure.
3
Differentiate JSON syntax from XML and HTTP verb body mechanics.
Angle brackets belong to XML, and HTTP GET requests typically do not carry request payload bodies.
HTTP GET operations are read-only calls designed to fetch information defined by endpoint URIs.

Key Concept

JSON Data Format Structure and Characteristics in REST APIs
Question 40Question →

A network administrator is evaluating the operational architecture of a software-defined networking (SDN) deployment compared to an existing traditional campus infrastructure. The management application needs to push business intent and policy changes dynamically to a centralized SDN controller, which subsequently programs the physical network devices across the fabric. Which statement accurately describes the interface roles and communication protocols used in this controller-based architecture?

Show answer & explanation

Answer: Northbound APIs use RESTful HTTP calls to communicate intent between management applications and the controller, while Southbound APIs use protocols such as NETCONF or RESTCONF to program the network devices.

Answer

Northbound APIs use RESTful HTTP calls to communicate intent between management applications and the controller, while Southbound APIs use protocols such as NETCONF or RESTCONF to program the network devices.
In a software-defined controller-based network, the control plane is centralized within the SDN controller. Management applications communicate with the controller via Northbound APIs (typically RESTful APIs using HTTP/HTTPS). The controller then translates application requests into network device configurations and communicates down to physical switches and routers via Southbound APIs (using protocols such as NETCONF, RESTCONF, or OpenFlow) to update data plane forwarding behavior.

Step-by-Step Solution

1
Analyze the SDN control plane abstraction architecture
Identify that controller-based networking splits architectural interaction into Northbound (above the controller) and Southbound (below the controller) interfaces.
Traditional networks run control plane protocols locally on each device, whereas SDN centralizes control logic on a controller positioned between management apps and network hardware.
2
Evaluate Northbound API functions and protocols
Determine that applications program network intent into the controller via RESTful APIs using standard HTTP verbs (GET, POST, PUT, DELETE).
Northbound APIs abstract underlying topology details and expose programmatic interfaces to higher-level orchestrators.
3
Evaluate Southbound API functions and protocols
Determine that the controller uses Southbound mechanisms (NETCONF, RESTCONF, gNMI, OpenFlow) to communicate policies to physical switches and routers.
Southbound protocols relay control instructions down to the data plane hardware to update forwarding tables.

Key Concept

Comparing Traditional Networks with Controller-Based Networking
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