Cisco 300-635 Exam Dumps & Practice Test Questions

Question 1:

What are two valid advantages of using network configuration automation tools such as Ansible and Puppet in a data center environment? (Choose two.)

A. Consistency of systems configuration
B. Automation of repetitive tasks
C. Ability to organize devices by interface groups
D. Capability to configure VLANs and routing per device
E. Elimination of network protocols like Spanning Tree

Answer: A, B

Explanation:

Automation tools like Ansible and Puppet have become essential in managing modern data center networks due to their ability to streamline and standardize complex configurations. These tools bring several key benefits that enhance both operational efficiency and network reliability.

A. Consistency of systems configuration is a fundamental strength of configuration management tools. In large-scale environments, manual configurations often lead to inconsistencies, commonly known as “configuration drift.” This drift can cause unpredictable behavior and security vulnerabilities. By leveraging tools like Ansible and Puppet, administrators can define system configurations using declarative templates or playbooks. These templates ensure that every system gets the same configuration, reducing discrepancies and maintaining uniformity across servers, switches, routers, and other devices.

B. Automation of repetitive tasks is another major benefit. Network engineers frequently perform the same tasks across multiple systems—whether it’s applying software updates, changing access credentials, or deploying services. Automating these actions eliminates the need for manual execution, which in turn speeds up deployment times and minimizes the risk of human error. Repetitive configurations that once took hours can now be completed in minutes through automation scripts.

As for the remaining options:

• C. Creating device and interface groups is indeed possible with automation tools for better resource organization. However, it’s more of a secondary feature than a core benefit.

• D. Adding VLANs and routes per device can certainly be done with Ansible or Puppet, but this reflects a task that’s automated—not a unique benefit in itself. The core advantage lies in the ability to execute such tasks consistently and at scale.

• E. Removing protocols like Spanning Tree is a design-level decision. It is not directly related to the function of automation tools, which are focused on enforcing configurations rather than replacing or eliminating fundamental networking protocols.

In summary, the two best answers are A and B. These reflect the primary strengths of using Ansible and Puppet: maintaining uniformity across configurations and reducing manual workload through automated processes.

Question 2:

A developer wants to test a newly discovered Python package without affecting the main project code. What is the best way to safely isolate this package for testing purposes?

A. Add the new package to your requirements.txt file
B. Set up a new virtual machine and install the package with pip
C. Install the package on your main system as root
D. Create a virtual environment and install the package within it

Answer: D

Explanation:

When testing or experimenting with a new Python package, it is crucial to prevent interference with your main code base and its existing dependencies. One of the most effective and commonly used methods for isolating Python packages is to use a virtual environment.

A virtual environment provides a self-contained Python environment that allows the developer to install packages without modifying the global Python interpreter or affecting other projects. Using tools like venv (which comes built into Python 3) or virtualenv, developers can create an isolated workspace. Once the virtual environment is activated, packages installed using pip are confined to that environment, keeping the main system untouched.

Let’s evaluate each option:

• A. Adding the package to requirements.txt makes it a dependency of your project. This action is counterproductive when you want to isolate the package. It affects the main code base and might introduce unwanted dependencies or conflicts.

• B. Creating a virtual machine does provide complete isolation, including OS-level, but it is resource-heavy and unnecessary for simply testing a Python package. It adds overhead in terms of setup and resource consumption.

• C. Installing the package globally as root is the least recommended. It can alter system-wide dependencies, potentially breaking existing applications or introducing conflicts. It also poses a security risk.

• D. Creating a virtual environment and installing the package within it is the most efficient and safest approach. It keeps the new package isolated, prevents interference with your main project, and is easy to manage and discard when no longer needed.

Thus, Option D is the correct and best solution. It ensures flexibility, control, and clean testing without risking the integrity of your existing setup.

Question 3:

Which two statements accurately describe the characteristics of gRPC? (Choose two.)

A. It is considered a draft by the IETF
B. It has been formalized as an IETF standard
C. It operates using the SSH protocol
D. It is a publicly available open-source project
E. It uses HTTPS for secure communication

Correct Answers: D, E

Explanation:

gRPC is a high-performance, open-source remote procedure call (RPC) framework developed by Google. It enables seamless communication between distributed systems and is designed for speed, scalability, and efficiency—primarily using HTTP/2 and Protocol Buffers (Protobuf) for serialization.

Let’s evaluate each option in context:

• A. It is considered a draft by the IETF:
  This is incorrect. gRPC is not recognized as an IETF draft. While gRPC is built on top of technologies like HTTP/2, which is an IETF standard, the gRPC protocol itself is not under review or publication by the Internet Engineering Task Force. It remains an open-source project governed by community contribution rather than formal standardization.

• B. It has been formalized as an IETF standard:
  Also incorrect. gRPC has not been submitted or accepted as an IETF standard. It remains independent and outside the IETF's formal standards process.

• C. It operates using the SSH protocol:
  This is false. gRPC does not use SSH (Secure Shell) as a transport layer. Instead, it relies on HTTP/2, which offers multiplexing, header compression, and persistent connections. For secure data transfer, gRPC uses TLS (Transport Layer Security), which is what powers HTTPS, not SSH.

• D. It is a publicly available open-source project:
  This is correct. gRPC was open-sourced by Google and is now maintained under the Cloud Native Computing Foundation (CNCF). Its source code is freely available on GitHub, and it supports multiple programming languages, encouraging broad adoption and community-driven development.

• E. It uses HTTPS for secure communication:
  This is correct. gRPC typically runs on HTTP/2, and when TLS is applied to secure the communication channel, it becomes HTTPS. This ensures that all data transmitted between services is encrypted, maintaining confidentiality and integrity.

The two correct statements are D and E. gRPC is an open-source project (D), and it transmits data securely over HTTPS (E), leveraging HTTP/2 and TLS to offer both performance and security.

Question 4:

What is a true statement regarding the behavior of synchronous and asynchronous API calls?

A. A synchronous API call waits for a response before proceeding
B. Synchronous APIs are more difficult to monitor and debug
C. Synchronous API calls must always be routed through a proxy
D. Asynchronous calls create additional overhead during client authentication

Correct Answer: A

Explanation:

Understanding the distinction between synchronous and asynchronous API calls is vital for designing scalable and responsive applications. The key difference lies in how the client handles waiting for a server response.

Let’s explore each option:

• A. A synchronous API call waits for a response before proceeding:
  This is correct. In synchronous communication, the client sends a request and waits for the server to respond before continuing with any other operation. This linear and blocking behavior ensures that the result is immediately available to the client but can lead to delays if the server takes a long time to respond. This model is simple and easy to implement but less suitable for applications that require high concurrency or non-blocking behavior.

• B. Synchronous APIs are more difficult to monitor and debug:
  This is false. In fact, synchronous communication is easier to trace and debug because the flow of operations is predictable and sequential. Developers can easily map a request to its response and identify failures at specific points in the cycle.

• C. Synchronous API calls must always be routed through a proxy:
  This is incorrect. While a proxy may be used for reasons such as security, caching, or load balancing, it is not a requirement for synchronous API calls. A direct client-server communication is perfectly valid in a synchronous model without the need for intermediaries.

• D. Asynchronous calls create additional overhead during client authentication:
  This is inaccurate. Asynchronous communication does not inherently introduce more authentication overhead. In many cases, it can actually improve efficiency by allowing the client to send multiple requests concurrently and handle responses as they arrive, often using mechanisms like callbacks or message queues.

The correct statement is A. Synchronous API calls are characterized by a blocking nature where the client waits for a response before executing further instructions. This ensures simplicity and predictability but can impact performance in time-sensitive or highly concurrent systems.

Question 5:

Which two principles are fundamental to REST architecture? (Select two options.)

A. cacheable
B. trackable
C. stateless
D. single-layer system
E. stateful

Answer: A, C

Explanation:

REST (Representational State Transfer) is an architectural style used for designing scalable web services. It defines a set of constraints that ensure that applications remain lightweight, flexible, and easy to scale. Among these, two of the most important guiding principles are statelessness and cacheability.

Statelessness is central to REST. Each client request to a server must contain all the information necessary to understand and process the request. The server should not store any information about the client's session or previous interactions. This simplifies server design, reduces memory overhead, and enhances scalability. With no session state maintained on the server, RESTful services can be distributed easily across multiple nodes, making horizontal scaling straightforward.

Cacheability is another crucial principle of REST. It allows responses from the server to be labeled as either cacheable or non-cacheable. When a response is cacheable, the client (or an intermediate proxy) can store and reuse that response for future requests. This reduces the number of calls made to the server, improves application performance, minimizes bandwidth usage, and decreases server load. Proper caching strategies in RESTful systems play a major role in enhancing responsiveness and efficiency.

Now let’s explore the incorrect options:

B. Trackable is not a guiding principle of REST. While API interactions can be monitored or logged for analytical or debugging purposes, "trackable" is not a constraint defined in REST’s architectural style.

D. Single-layer system is also incorrect. REST supports multi-layered system designs. These layers may include intermediaries such as load balancers, proxies, or gateways. In fact, REST explicitly allows for layered system architecture, where each layer cannot see beyond the immediate layer it is interacting with, increasing system modularity and security.

E. Stateful directly contradicts REST principles. A stateful system maintains client context between requests, which REST seeks to avoid. Statelessness ensures that each request is self-contained, making the application more scalable and fault-tolerant.

In summary, stateless operations and cacheable responses are foundational to the design of RESTful systems. They enable scalability, improve performance, and simplify architecture. Therefore, the correct answers are A and C.

Question 6:

What is the function of this ACI Cobra Python code when executed?

A. It displays all LLDP neighbor MAC and IP addresses.
B. It displays all CDP neighbor MAC and IP addresses.
C. It displays all endpoint MAC and IP addresses.
D. It displays all APIC MAC and IP addresses.

Answer: A

Explanation:

Cisco ACI (Application Centric Infrastructure) provides a powerful automation and management framework for data center networks. Cobra is the Python SDK (Software Development Kit) provided by Cisco to interact programmatically with the ACI fabric using the RESTful API exposed by the APIC (Application Policy Infrastructure Controller).

In this context, the Cobra Python code is likely designed to interact with the ACI’s Managed Object (MO) model to extract specific data. The question revolves around identifying the outcome of a Python script that uses Cobra to fetch and print MAC and IP address details from the ACI environment.

The key is the reference to LLDP (Link Layer Discovery Protocol). LLDP is a vendor-neutral, layer 2 protocol used by network devices to advertise identity and capabilities and discover neighbors on the same physical link. It allows the APIC to detect directly connected devices and collect details like their MAC and IP addresses.

Given that the Python code is focused on printing LLDP data, it's safe to infer that the script pulls information specifically related to LLDP neighbors, including their MAC and IP addresses. This makes A the correct answer.

Let’s consider why the other options are incorrect:

B. CDP neighbor MAC and IP addresses: CDP (Cisco Discovery Protocol) is Cisco’s proprietary protocol for similar neighbor discovery, but it is not the one being referenced here. If the code used CDP-specific MOs, this might have been correct. However, the mention of LLDP clearly rules this out.

C. Endpoint MAC and IP addresses: While endpoint information (connected servers, VMs, etc.) can also be queried via Cobra, that would involve querying different MOs focused on endpoint learning, such as fvCEp. LLDP, on the other hand, focuses on devices directly connected via interfaces.

D. APIC MAC and IP addresses: The APIC controllers themselves are not discovered via LLDP. LLDP is used to learn about neighboring physical or logical devices on the network, not about the controller's own attributes.

Therefore, the code’s purpose is to extract LLDP neighbor information—specifically, their MAC and IP addresses—making A the correct choice.

Question 7:

In a newly initialized ACI environment, what outcome can be expected when the given script is executed?

A. Ten objects are both created and deleted
B. Nine objects are successfully created
C. An error occurs during execution
D. All ten objects are created

Correct Answer: C

Explanation:

When working with a fresh ACI (Application Centric Infrastructure) setup, executing a script that interacts with the environment—especially one that creates or modifies configuration objects—can often result in execution errors if the script makes incorrect assumptions or contains improper logic. Let's explore what typically causes these issues and why an exception is the most probable outcome in this case.

ACI scripts generally interact with the APIC (Application Policy Infrastructure Controller) to define or manage various networking constructs like tenants, application profiles, endpoint groups, and bridge domains. These operations are performed using RESTful APIs, and automation tools like Python scripts with the ACI SDK (such as Cobra or Arya).

In a new ACI environment, no prior configurations exist. This can present a clean slate, but also a potential challenge if the script assumes the presence of certain dependencies, default configurations, or pre-created parent objects. For example, a script trying to create a bridge domain within a tenant must ensure the tenant already exists—or include the logic to create the tenant beforehand. If the script omits such a step or references non-existent objects, an exception is thrown.

Additionally, exceptions can also arise from syntax errors, incorrect API calls, authentication issues, or invalid object relationships. If the script attempts to delete objects that haven’t been created yet, or attempts operations in an incorrect sequence, the APIC will flag these inconsistencies, leading to runtime errors.

Let’s assess the answer options:

• A suggests that all ten objects are created and then deleted. This could be possible only if the script is error-free and accounts for object lifecycle correctly—unlikely on a first run in a new instance.

• B implies partial success, which might indicate one failure, but without specific evidence of such behavior, it's speculative.

• C is the most logical conclusion. In most real-world scenarios, a script running in a new ACI environment—especially without detailed error handling—would encounter an exception due to unhandled edge cases.

• D would only happen if everything were perfectly aligned, which isn't the expected behavior in this context.

Thus, given the nature of ACI scripting and the complexities of object dependencies, an exception being thrown is the most likely result when a script runs against a fresh ACI instance without sufficient pre-validation or setup.

Question 8:

What is the primary function of Cisco ACI in modern data center environments?

A. Automating server virtualization
B. Delivering policy-based automation and programmable networking
C. Handling database communication
D. Facilitating IPv6 routing features

Correct Answer: B

Explanation:

Cisco’s Application Centric Infrastructure (ACI) is a transformative approach to data center networking that shifts the focus from manual network configurations to intent-based, policy-driven automation. Unlike traditional network setups that require extensive device-by-device configuration, ACI introduces a central controller-based architecture that abstracts the hardware layer and treats the network as a programmable entity.

At its core, Cisco ACI is an SDN (Software-Defined Networking) solution that promotes automation, centralized management, and alignment of network behavior with application needs. This is achieved by defining policies that determine how applications, users, and workloads should interact with each other. Rather than adjusting VLANs, access control lists, or individual switch configurations manually, network operators can now define high-level intent (e.g., allow app tier A to talk to app tier B) and let ACI enforce these rules across the entire fabric.

One of the most compelling features of ACI is its ability to adapt dynamically to changing application requirements. Whether applications are scaled out, moved to different servers, or provisioned in different zones, ACI updates the network behavior in real-time, ensuring that connectivity, security policies, and performance optimizations follow the application lifecycle.

Furthermore, Cisco ACI improves operational efficiency by simplifying the deployment of new services. Through APIs, templates, and integration with tools like Ansible and Terraform, it enables rapid deployment and consistent configuration practices, reducing the risk of misconfiguration. This capability becomes crucial in hybrid and multi-cloud environments, where scalability and agility are essential.

Let’s evaluate the other options:

• A relates more to hypervisors and virtualization platforms like VMware or Hyper-V rather than network infrastructure.

• C narrows ACI’s role too specifically to databases, which are just one of many types of traffic handled by a data center network.

• D is a capability that exists within ACI, but it is not its primary function.

Ultimately, Cisco ACI's primary value lies in providing a policy-driven, automated, and programmable framework for data center networking—making B the most accurate answer.

Question 9:

Which Python library is most commonly utilized for automating tasks and establishing SSH connections to Cisco network devices?

A. Ansible
B. Netmiko
C. Pytest
D. Flask

Explanation:

In the realm of data center automation, Python has become an essential language for scripting and automating tasks. When it comes to interacting with Cisco network devices over SSH, Netmiko is a standout Python library purpose-built for this exact use case.

Netmiko is an open-source library developed by network engineer Kirk Byers to simplify the use of Python for network automation tasks. It extends the capabilities of the Paramiko SSH library by offering device-type specific handling for command execution, session management, and output parsing. This library significantly reduces the complexity that would otherwise be required to handle multi-vendor device interactions manually.

Netmiko supports a broad range of network devices from multiple vendors such as Cisco, Juniper, Arista, HP, and more. For Cisco devices in particular—be it routers, switches, or firewalls—Netmiko enables network engineers to write Python scripts that automate repetitive configurations, execute show commands, and retrieve diagnostics information easily. These operations can be run sequentially or in parallel, allowing for efficient network management across a fleet of devices.

The power of Netmiko lies in its simplicity. The library abstracts the intricate details of establishing SSH connections and device-specific syntax, allowing engineers to focus on the logic of automation rather than low-level protocol handling. For example, you can easily send a set of configuration commands to a router or collect outputs from multiple switches using a few lines of Python code.

While Ansible is also widely used for automation, it operates at a higher abstraction level and is based on YAML playbooks. Ansible’s modules wrap around libraries like Netmiko or NAPALM under the hood, but Netmiko offers more granular control when scripting directly in Python.

The other options—Pytest and Flask—serve different purposes altogether. Pytest is a framework used for unit testing in Python projects and has no native functionality related to network device management. Flask is a micro web framework for building web applications and APIs and is unrelated to network automation tasks.

In summary, Netmiko is a lightweight, highly efficient, and Pythonic way to interact with Cisco devices via SSH. It is ideal for engineers looking to automate tasks like configuration deployment, output collection, and real-time diagnostics in a data center or enterprise networking environment.

Question 10:

When using Ansible to automate tasks on Cisco Nexus switches, which module should be used to configure these devices?

A. ios_config
B. nxos_config
C. cisco_ise
D. ios_facts

Correct Answer: B

Explanation:

Ansible is a popular configuration management and automation tool that excels in managing both server and network infrastructures. For network automation, it provides an extensive set of modules designed to interact with various vendor platforms, including Cisco. When automating configuration tasks on Cisco Nexus switches—which run the NX-OS operating system—the appropriate module to use is nxos_config.

The nxos_config module enables users to push configurations, retrieve current running or startup configurations, and manage Nexus devices in a declarative manner. This means administrators describe the desired end state of the configuration, and Ansible ensures the target device reaches that state. It eliminates the need for manual logins and repetitive CLI commands, which enhances efficiency, reduces human error, and promotes configuration consistency across the network.

Cisco Nexus switches are widely deployed in data centers due to their scalability, high performance, and support for advanced features like VXLAN and EVPN. These devices have specific configuration syntax and operational behavior that differ from Cisco IOS-based devices. Hence, nxos_config is specially tailored to understand and manage these unique characteristics.

Let’s briefly examine the incorrect options:

• ios_config is used for Cisco devices that run the traditional IOS operating system, such as Catalyst switches and ISR routers. It cannot properly handle the syntax or command structure of NX-OS.

• cisco_ise is associated with Cisco Identity Services Engine (ISE), which is a platform used for access control and identity management—not for configuring switches.
  
  

• ios_facts is used to gather system information (facts) about Cisco IOS devices, like hardware models, interface details, and OS versions, but it does not allow for applying configurations.

The nxos_config module allows network teams to treat infrastructure as code, ensuring that all configurations are version-controlled and reproducible. This is particularly useful for large-scale environments where changes must be validated and rolled out consistently. In addition, Ansible’s integration with platforms like Git and Jenkins means that network automation can be part of a broader DevOps or NetDevOps pipeline.

In conclusion, nxos_config is the optimal Ansible module for automating the configuration of Cisco Nexus switches, providing both power and flexibility to network administrators in complex data center environments.