Cisco 300-535 Practice Test Questions, Exam Dumps

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300-535 Cisco Practice Test Questions and Exam Dumps

Question 1

What tool is used to perform a "what if" failure analysis in a service provider network that is running Segment Routing?

A. Cisco WAN Automation Engine
B. Cisco Evolved Programmable Network Manager
C. Cisco Network Services Orchestrator
D. Cisco Segment Routing Path Computation Element

Correct answer: A

Explanation:

In a Segment Routing (SR) environment, operators require powerful tools to simulate traffic flows, evaluate path behaviors, and assess how network failures or changes might impact service availability. The "what if" failure analysis is a proactive method of modeling the impact of potential issues before they occur, such as link or node failures, and finding alternative paths for traffic.

Cisco WAN Automation Engine (WAE)

Cisco WAE is a robust tool specifically designed for network modeling, analysis, and optimization. It provides capabilities such as:

"What-if" simulations: WAE enables engineers to model hypothetical network events, including failures or congestion scenarios. This allows for analysis of service impact and rerouting efficiency in an SR-based network.
Path computation and optimization: It leverages traffic engineering data to compute optimal paths based on constraints like bandwidth, latency, and policy rules.
Visualization and forecasting: WAE can display current and projected network states, helping in capacity planning and proactive remediation.

This makes Cisco WAE the most appropriate tool for simulating network behavior under potential failure conditions in a Segment Routing-enabled environment.

Why the Other Options Are Incorrect:

B. Cisco Evolved Programmable Network Manager (EPN-M):
EPN-M focuses on element and network management, offering visualization, configuration, and fault monitoring. It is not primarily used for simulating or modeling “what if” scenarios.
C. Cisco Network Services Orchestrator (NSO):
NSO is designed for service lifecycle automation, particularly for deploying and managing services across multi-vendor networks. It does not have simulation capabilities for analyzing failure impacts in an SR network.
D. Cisco Segment Routing Path Computation Element (SR-PCE):
While the SR-PCE computes optimal paths for Segment Routing, it does not offer simulation or failure modeling tools. It is responsible for live, real-time path computation, not for hypothetical scenario planning.

For performing a "what if" failure analysis in a service provider network running Segment Routing, Cisco WAN Automation Engine (WAE) provides the most appropriate simulation and path computation capabilities.

Question 2

Refer to the exhibit. An engineer implements an automation with Cisco XTC. Which problem results in the 404 Not Found error code on the REST call?

A. The resource that you are trying to delete does not exist.
B. Port 8080 is not enabled on XTC.
C. XTC does not offer any APIs.
D. You must change the request method.

Correct answer: A

Explanation:

The HTTP status code 404 Not Found indicates that the client was able to communicate with the server, but the server could not find the requested resource. This is a common response when the URL path is incorrect or when the specific resource at the given path does not exist.

Analysis of the Exhibit

Let’s dissect the curl request in the exhibit:

curl --request DELETE --url http://10.1.1.1:8080/srpolicy-install \

--header 'cache-control: no-cache' \

--header 'content-type: application/json' \

--data '{"source": "1.1.1.2", “end-point”: “2001:4860::1:1:1”, “color”: 99, “route-distinguisher”: 2}'

This command is attempting to delete a resource using a DELETE HTTP method.
The target URL is http://10.1.1.1:8080/srpolicy-install.
The payload suggests it is trying to delete a Segment Routing (SR) policy based on given parameters.
The server responded with a 404 Not Found, and the body indicates that the path /srpolicy-install could not be found on the server.

Why the Correct Answer Is A

A. The resource that you are trying to delete does not exist.
This is the most accurate explanation. The 404 error is a direct result of the resource path being incorrect or the resource itself not existing. If the srpolicy-install entry doesn't exist, the server will return a 404.

Why the Other Options Are Incorrect

B. Port 8080 is not enabled on XTC.
If this were true, the server would not respond at all, or a Connection refused or Timeout error would occur. But since a 404 is returned, port 8080 is clearly reachable and active.
C. XTC does not offer any APIs.
This is not correct. Cisco XTC (Crosswork Traffic Controller) does provide APIs. The 404 response proves that the server is up and capable of handling requests—it just doesn’t recognize this specific resource path.
D. You must change the request method.
The DELETE method is valid for removing resources in RESTful APIs. If the request method were invalid, a 405 Method Not Allowed would be the correct error code, not 404.

The presence of a 404 Not Found error, while using the correct HTTP method and accessing a reachable port, clearly indicates that the resource does not exist on the server. The engineer is likely trying to delete a resource (an SR policy) that either was never installed or has already been removed.

Question 3

Which two Python libraries are used to write a script to retrieve network device information using RESTCONF? (Choose two.)

A. PySNMP
B. requests
C. ncclient
D. YANG
E. json

Correct answers: B, E

Explanation:

RESTCONF is a protocol that allows for accessing and configuring data on a network device using HTTP methods (like GET, POST, PUT, DELETE). It leverages data models defined in YANG and returns or sends data typically in JSON or XML format.

When writing a Python script to retrieve information from a network device using RESTCONF, the script must be capable of:

Making HTTP or HTTPS requests to a network device.
Parsing and processing the response, typically in JSON format.

Correct Options:

B. requests
The requests library is one of the most commonly used Python libraries for making HTTP and HTTPS requests. It supports all necessary HTTP methods (GET, POST, etc.), basic authentication, custom headers, and SSL certificate handling, which are essential when interacting with RESTCONF endpoints on network devices.
E. json
RESTCONF APIs commonly return structured data in JSON format. The json library, included in the Python standard library, allows the parsing of JSON-formatted response payloads into Python dictionaries, making it possible to extract specific data fields from RESTCONF responses.

Why the Other Options Are Incorrect:

A. PySNMP
This library is used for Simple Network Management Protocol (SNMP) operations, not RESTCONF. SNMP and RESTCONF are entirely different protocols.
C. ncclient
ncclient is a Python library specifically used for NETCONF, not RESTCONF. NETCONF and RESTCONF are both used for configuration management and retrieval but over different protocols.
D. YANG
YANG is not a Python library. It is a data modeling language used to model configuration and state data manipulated by NETCONF and RESTCONF. While RESTCONF uses YANG-modeled data, YANG itself is not a Python package you import or use to make requests.

To communicate with RESTCONF-enabled network devices in Python, the script needs:

An HTTP client library like requests to send REST calls.
A data parser like json to handle responses.

Question 4

Which command configures the remote peer when the Cisco IOS XR Traffic Controller is used?

A. peer-sync ipv4 192.168.0.3
B. state ipv4 192.168.0.3
C. peer ipv4 192.168.0.3
D. state-sync ipv4 192.168.0.3

Answer: D

Explanation:

In Cisco IOS XR, the Traffic Controller (XTC) utilizes the Path Computation Element Communication Protocol (PCEP) to manage and compute paths within a network. To establish communication between the XTC and its remote peer, the state-sync ipv4 command is employed. This command configures the remote peer for state synchronization, ensuring that the XTC can exchange state information with the peer router, which is essential for accurate path computation and network topology awareness.

The other options provided are not valid commands for configuring a remote peer in the context of the Cisco IOS XR Traffic Controller:

A. peer-sync ipv4 192.168.0.3: This command does not exist in the Cisco IOS XR command set for Traffic Controller configuration. It is not recognized as a valid command for establishing a remote peer.
B. state ipv4 192.168.0.3: The state command is used to display the state of a peer router in a group, not to configure a remote peer. It does not initiate or configure any synchronization with a remote peer.
C. peer ipv4 192.168.0.3: While the peer command is used in various contexts to define peer relationships, it is not the correct command for configuring a remote peer in the Traffic Controller context. The correct command for this purpose is state-sync ipv4.

Therefore, the correct command to configure the remote peer when using the Cisco IOS XR Traffic Controller is state-sync ipv4 192.168.0.3. This command ensures that the XTC can synchronize state information with the specified remote peer, facilitating effective path computation and network management.

Question 5

An automation engineer is trying to configure a destination group to use dial-out telemetry with gRPC on a Cisco IOS XR platform. The template created is failing to apply. Which parameters must be configured?

A. source IP address, source port, encoding, and sampling interval
B. source IP address, source port, encoding, and protocol
C. destination IP address, destination port, encoding, and sensor path
D. destination IP address, destination port, encoding, and protocol

Answer: D

Explanation:

In Cisco IOS XR, configuring dial-out telemetry with gRPC involves setting up a destination group that specifies how and where telemetry data should be sent. The key parameters required for this configuration are:

Destination IP address: This is the IP address of the system or application that will receive the telemetry data. It must be a valid and reachable address within the network.
Destination port: This is the port on which the destination system is listening for incoming telemetry data. The port must be open and properly configured to accept connections.
Encoding: This refers to the format in which the telemetry data is serialized. Supported encoding formats include self-describing-gpb (Google Protocol Buffers), JSON, and Protobuf. The choice of encoding affects how the data is structured and interpreted by the receiver.
Protocol: This specifies the transport protocol used to send the telemetry data. For dial-out telemetry, the protocol is typically gRPC, which allows the router to initiate a session to the collector and stream data.

These parameters are configured under the destination group using the following commands:

RP/0/RP0/CPU0:SunC(config)#telemetry model-driven

RP/0/RP0/CPU0:SunC(config-model-driven)#destination-group DGroup2

RP/0/RP0/CPU0:SunC(config-model-driven-dest)#address family ipv4 172.30.8.4 port 57500

RP/0/RP0/CPU0:SunC(config-model-driven-dest-addr)#encoding self-describing-gpb

RP/0/RP0/CPU0:SunC(config-model-driven-dest-addr)#protocol grpc

RP/0/RP0/CPU0:SunC(config-model-driven-dest-addr)#commit

In this configuration:

The destination IP address is set to 172.30.8.4.
The destination port is set to 57500.
The encoding is set to self-describing-gpb.
The protocol is set to grpc.

These settings ensure that the router can establish a gRPC session with the specified destination and stream telemetry data in the correct format.

The other options are incorrect because they either include parameters that are not required for the destination group configuration (such as source IP address, source port, or sensor path) or omit essential parameters like the destination address and protocol. Therefore, D is the correct answer.

Question 6

Which two use cases are valid for Cisco WAN Automation Engine? (Choose two.)

A. deployment of SR policies
B. integration with Cisco XTC
C. what-if analysis
D. device manager
E. network controller

Answer: B, C

Explanation:

Cisco WAN Automation Engine (WAE) is a comprehensive network design and planning tool that enables network operators to visualize, simulate, and optimize their networks. It provides a digital representation of the network, allowing for detailed analysis and decision-making. Among its various capabilities, two key use cases stand out:

Integration with Cisco XTC: Cisco WAE can be integrated with Cisco Crosswork Traffic Controller (XTC), which is responsible for managing traffic engineering and path computation in the network. This integration allows for the delegation of bandwidth-aware path computation for Segment Routing (SR) policies to WAE. By leveraging WAE's detailed network models and simulation capabilities, XTC can make more informed decisions about traffic routing and optimization. This collaboration enhances the overall efficiency and performance of the network by ensuring that traffic is routed in an optimal manner, considering current network conditions and future demands.
What-if analysis: One of the core functionalities of Cisco WAE is its ability to perform what-if analysis. This feature enables network engineers to simulate various scenarios and assess the potential impact of changes in the network. For instance, they can model the effects of adding new traffic demands, modifying existing paths, or introducing network failures. By analyzing these scenarios, engineers can make proactive decisions to optimize network performance, plan for future growth, and mitigate potential issues before they occur. This predictive capability is invaluable for maintaining a resilient and efficient network infrastructure.

The other options are less relevant in the context of Cisco WAE:

Deployment of SR policies: While Cisco WAE provides the tools to design and simulate SR policies, the actual deployment of these policies is typically handled by other components like Cisco XTC. WAE's role is more focused on planning and optimization rather than direct deployment.
Device manager: Cisco WAE is not a device management tool. It does not handle tasks such as configuring or monitoring individual network devices. Instead, it focuses on providing a high-level view of the network for planning and optimization purposes.
Network controller: While Cisco WAE can integrate with network controllers to inform them of optimal paths and configurations, it is not a network controller itself. Its primary function is to provide insights and simulations to aid in network planning and decision-making.

In summary, Cisco WAE's integration with Cisco XTC and its ability to perform what-if analysis are two of its most significant use cases, enabling network operators to design, simulate, and optimize their networks effectively.

Question 7

Which schema allows device configuration elements to be enclosed within a remote procedure call message when NETCONF is implemented?

A. JSON-RPC
B. XML
C. YAML
D. JSON

Answer: B

Explanation:

NETCONF (Network Configuration Protocol) is a standardized protocol defined by the IETF for managing and configuring network devices. One of the key aspects of NETCONF is its use of XML (Extensible Markup Language) to encode both the protocol messages and the configuration data. This XML-based approach provides a structured and extensible format that facilitates the exchange of configuration information between network devices and management systems.

NETCONF Message Structure

In NETCONF, communication between the client and server is conducted through Remote Procedure Calls (RPCs). These RPCs are encapsulated within XML messages, which include various elements such as:

<rpc>: The root element of a NETCONF RPC message, which contains the operation to be performed.
<rpc-reply>: The response element that contains the result of the RPC operation.
<data>: The element that holds the configuration data or operational state information.
<error>: The element that provides error information if the operation fails.

For example, a typical NETCONF RPC message to retrieve configuration data might look like this:

xml

CopyEdit

<get-config>

</source>

</get-config>

</rpc>

In this example, the <rpc> element encloses the <get-config> operation, which requests the running configuration from the device. The message is encoded in XML, adhering to the NETCONF protocol specifications.

Use of XML in NETCONF

The use of XML in NETCONF provides several advantages:

Standardization: XML is a widely adopted standard for data representation, ensuring interoperability between different systems and vendors.
Extensibility: XML's hierarchical structure allows for easy extension and customization, accommodating various configuration models and data schemas.
Validation: XML documents can be validated against XML Schema Definitions (XSDs), ensuring that the data conforms to the expected structure and data types.
Human-Readability: While XML can be verbose, it is human-readable and can be edited manually if necessary.

Alternatives to XML

While XML is the standard encoding format for NETCONF, other data serialization formats like JSON (JavaScript Object Notation) and YAML (YAML Ain't Markup Language) have gained popularity in other areas of network automation and configuration management. However, these formats are not natively supported by NETCONF for encoding RPC messages. For instance:

JSON: While JSON is widely used in RESTful APIs and other protocols, NETCONF does not use JSON to encode its RPC messages. Instead, NETCONF relies on XML for message encoding.
YAML: YAML is often used for configuration files due to its readability, but it is not used in NETCONF RPC messages.
JSON-RPC: This is a remote procedure call protocol encoded in JSON, but it is distinct from NETCONF and is not used in NETCONF implementations.

In summary, when implementing NETCONF, device configuration elements are enclosed within RPC messages that are encoded using XML. This XML-based approach is integral to the NETCONF protocol, providing a standardized and extensible framework for network device configuration and management. Therefore, the correct answer is B. XML.

Question 8

What is a key feature of YANG?

A. use identification
B. error prediction
C. JAVA compatibility
D. reusable types and groupings

Answer: D

Explanation:

YANG (Yet Another Next Generation) is a data modeling language developed by the IETF to define data models for network configuration and management. One of its most significant features is the ability to define reusable types and groupings, which enhances modularity and maintainability in network automation.

Reusable Types

YANG allows the definition of derived types using the typedef statement. This enables the creation of custom data types based on existing YANG types, with additional constraints such as value ranges or patterns. For example, a percentage type can be defined as a uint8 with a range of 0 to 100. This approach promotes consistency and reduces redundancy by reusing these custom types across different modules and instances.

Reusable Groupings

The grouping statement in YANG defines a set of schema nodes that can be reused across different parts of a module or in other modules. This is akin to creating a "template" that can be instantiated multiple times, ensuring consistency and reducing duplication. For instance, a grouping for network interface parameters can be defined once and reused wherever interface configurations are needed. This modular approach simplifies the management of complex configurations and enhances the maintainability of YANG models.

Benefits of Reusability in YANG

Consistency: By reusing types and groupings, network models maintain uniformity across different configurations, reducing the risk of errors and inconsistencies.
Maintainability: Updates to a reusable type or grouping need to be made only once, propagating changes throughout all instances where they are used.
Modularity: Network models become more modular, allowing for easier extensions and adaptations to new requirements without overhauling existing configurations.

Other Options Analysis

A. use identification: While YANG supports the definition of identities using the identity statement, this is not a primary feature and does not provide the same level of reusability as types and groupings.
B. error prediction: YANG does not inherently provide error prediction capabilities. It focuses on defining data models and constraints, but error handling is typically managed by the network management protocols (e.g., NETCONF, RESTCONF) that utilize YANG models.
C. JAVA compatibility: YANG is a data modeling language and is not inherently tied to any specific programming language, including Java. While tools exist to generate code in various languages from YANG models, Java compatibility is not a defining feature of YANG itself.

In conclusion, the ability to define reusable types and groupings is a cornerstone of YANG's design, facilitating the creation of modular, maintainable, and consistent network data models. Therefore, the correct answer is D.