25 Cisco Network Engineer Interview Questions and Answers

As a Cisco network engineer, you’re responsible for designing, installing, and maintaining the network infrastructure for businesses and organizations. This involves everything from configuring routers and switches to managing network security. In order to land a job as a Cisco network engineer, you’ll need to be able to answer common interview questions related to your experience and knowledge.

To help you get ready for your interview, we’ve compiled a list of Cisco network engineer interview questions and answers that you can use to develop your own responses.

1. Are you familiar with the OSI model and TCP/IP protocol suite?

The Open Systems Interconnection (OSI) model and TCP/IP protocol suite are two of the most important concepts in networking. The interviewer may ask this question to see if you have a basic understanding of these models and how they relate to each other. In your answer, try to explain what each is and describe their similarities and differences.

Example: “Yes, I am very familiar with the OSI model and TCP/IP protocol suite. As a Cisco Network Engineer, it is essential to have an understanding of these two models in order to properly configure and troubleshoot networks. I have extensive experience working with both models and understand their complexities.

The OSI model is a seven-layer network architecture that defines how data should be transferred between different systems. It provides guidelines for communication protocols such as Ethernet and Wi-Fi. I am well versed in configuring devices using this model and can easily identify any problems or issues related to its implementation.

Similarly, I am also knowledgeable about the TCP/IP protocol suite which is used to connect computers on a network. This includes IP addressing, routing protocols, DNS, DHCP, NAT, and more. I am confident in my ability to set up, configure, and manage these protocols to ensure efficient network performance.”

2. What are the differences between a star, bus and ring topology?

This question is a basic networking question that tests your knowledge of network topologies. Your answer should include the differences between each type and when you would use them.

Example: “The three main types of network topologies are star, bus, and ring. Each has its own advantages and disadvantages that make them suitable for different applications.

A star topology is the most common type of network topology used today. It consists of a central device (usually a switch or router) connected to each node in the network with dedicated point-to-point connections. This provides high performance and reliability as there is no single point of failure. However, it also requires more cabling than other topologies which can be expensive.

A bus topology uses a single cable to connect all nodes on the network. This makes it easy to set up and cost effective due to the minimal amount of cabling required. However, if this single cable fails then the entire network will go down.

Lastly, a ring topology connects all nodes together in a loop. Data travels around the loop from one node to another until it reaches its destination. This topology offers good performance and reliability but requires more cabling than the other two topologies.”

3. How would you troubleshoot a network with a high amount of packet loss?

This question is a great way to test your troubleshooting skills and how you apply them. You can answer this question by explaining the steps you would take to identify the source of packet loss, including what tools you would use to complete the task.

Example: “When troubleshooting a network with high packet loss, the first step is to identify the source of the problem. This can be done by running diagnostics such as ping tests and traceroutes to determine where the packets are being lost. Once the source has been identified, I would then analyze the data from the diagnostic tests to pinpoint the exact cause of the issue.

Once the root cause has been determined, I would take steps to resolve the issue. Depending on the cause, this could include updating firmware or drivers, reconfiguring settings, or replacing faulty hardware. If necessary, I would also work with other teams such as security or server operations to ensure that all components of the network are properly configured and secure.”

4. What is the difference between a switch and a router?

This question is a great way to test your knowledge of networking terminology. When answering this question, it can be helpful to define both terms and explain the differences between them in simple language.

Example: “A switch and a router are both network devices that enable communication between two or more networks. The main difference between them is the type of traffic they can handle. Switches are used to connect multiple computers, printers, and other devices on a single local area network (LAN). They use MAC addresses to forward data frames from one device to another within the same LAN. Routers, on the other hand, are used to connect different networks together. They use IP addresses to route packets from one network to another.

As a Cisco Network Engineer, I have extensive experience working with both switches and routers. I am well-versed in configuring and troubleshooting these devices for optimal performance. I also understand the importance of security protocols when it comes to networking equipment and ensure that all systems remain secure at all times.”

5. Provide an example of a time when you used a routing protocol to improve network performance.

This question is an opportunity to show your interviewer that you can use routing protocols in a practical way. You can describe the situation, what protocol you used and how it helped improve network performance.

Example: “I recently used a routing protocol to improve network performance for a client. The client had an existing network with multiple subnets and was experiencing slow response times when accessing resources across the different networks. To address this issue, I implemented OSPF (Open Shortest Path First) as their primary routing protocol. This allowed me to create a dynamic routing table that would automatically update itself based on changes in the network topology.

Once the new routing protocol was in place, I monitored the network traffic to ensure it was properly routed and optimized. I also configured QoS (Quality of Service) policies to prioritize certain types of traffic over others, such as VoIP or video streaming. Finally, I adjusted the MTU (Maximum Transmission Unit) size to reduce packet fragmentation and optimize throughput.

The result was a significant improvement in network performance. Response times were significantly reduced and users experienced less latency when accessing resources across the different networks. My client was very pleased with the results and thanked me for my work.”

6. If you were to design a network from scratch, what would be the key components you would include?

This question is a great way to assess your knowledge of networking and how you would approach the design process. When answering this question, it can be helpful to list out each component and why you would include them in your network.

Example: “When designing a network from scratch, there are several key components that I would include. First and foremost, I would ensure that the network is secure by implementing firewalls, intrusion detection systems, and access control lists. This will help protect the network from malicious attacks and unauthorized access.

Next, I would plan out the physical layout of the network, including cabling, routers, switches, and wireless access points. This will help optimize the performance of the network and provide redundancy in case of any hardware failures.

I would also configure Quality of Service (QoS) to prioritize certain types of traffic over others, such as voice or video. This will ensure that critical applications have the bandwidth they need to function properly.

Lastly, I would use monitoring tools to track the performance of the network, identify potential issues, and troubleshoot any problems that arise. This will help keep the network running smoothly and efficiently.”

7. What would you do if you noticed that employees were having trouble accessing certain websites from their work computers?

This question is a great way to test your problem-solving skills and ability to work with others. Your answer should include the steps you would take to address this issue, including who you would involve in the process and how you would communicate with them.

Example: “If I noticed that employees were having trouble accessing certain websites from their work computers, my first step would be to investigate the issue. I would start by running a network diagnostic test to identify any potential issues with the network infrastructure. This could include checking for packet loss, latency, and other performance metrics. After identifying any potential problems, I would then troubleshoot the issue further to determine the root cause.

Once I have identified the source of the problem, I will take the necessary steps to resolve it. This could involve reconfiguring routers or switches, updating firewall rules, or implementing new security protocols. Depending on the complexity of the issue, I may need to consult with other members of the IT team to ensure that all aspects of the issue are addressed. Ultimately, my goal is to provide a reliable solution that ensures employees can access the websites they need without interruption.”

8. How well do you understand the concept of subnetting?

Subnetting is a key concept in networking, and the interviewer may ask you this question to assess your knowledge of subnetting. In your answer, try to show that you understand how subnetting works and can use it when necessary.

Example: “I understand the concept of subnetting very well. I have been working with Cisco networks for over five years, and during that time I have become highly proficient in subnetting. I am familiar with all aspects of subnetting, from creating IP address ranges to assigning network masks. I also have experience troubleshooting complex routing issues related to subnets.

I have a deep understanding of how subnetting works and can easily explain it to others. I am comfortable using tools such as CIDR notation and VLSM to create efficient subnets. I am also knowledgeable about different types of subnetting such as static and dynamic, and I know when each type is best used.”

9. Do you have experience writing technical documentation related to networks?

This question can help the interviewer determine your experience with writing documentation and how you approach this task. Use examples from past projects to show that you are capable of completing this task independently.

Example: “Yes, I have extensive experience writing technical documentation related to networks. Throughout my career as a Cisco Network Engineer, I have written and maintained comprehensive network diagrams, configuration documents, and troubleshooting guides for various clients. I am also well-versed in creating detailed reports on the performance of existing networks, which has allowed me to identify areas of improvement and develop solutions accordingly.

I understand the importance of accurate and up-to-date technical documentation, especially when it comes to complex networks. As such, I always strive to ensure that all documentation is kept up-to-date and easily accessible to other members of the team. I also take pride in ensuring that all documentation is clear and concise so that anyone can quickly understand the information provided.”

10. When testing a new network, what would you do to ensure the security of the system?

This question is an opportunity to show your knowledge of network security and how you would apply it in a new role. When answering, consider the specific needs of the company you’re interviewing with and discuss what steps you would take to ensure their systems are secure.

Example: “When testing a new network, security is of the utmost importance. To ensure the system’s security, I would first audit the existing infrastructure and identify any potential vulnerabilities. This could include checking for outdated software or hardware, weak passwords, unsecured ports, etc. Once these issues have been identified, I would then create a plan to address them. This could involve implementing stronger authentication protocols, updating software and firmware, disabling unnecessary services, and configuring firewalls. Finally, I would perform regular vulnerability scans to detect any malicious activity or unauthorized access attempts. By taking these steps, I can guarantee that the system will be secure and compliant with industry standards.”

11. We want to make sure our network is compatible with the latest industry standards. What would you do to research these standards and incorporate them into our system?

This question is an opportunity to show your knowledge of industry standards and how you apply them to your work. You can discuss the process you use for researching these standards, as well as any certifications or training you have that allows you to understand these standards.

Example: “I understand the importance of staying up to date with industry standards when it comes to network engineering. To ensure our system is compatible, I would first research the latest standards and protocols for Cisco networks. This could include reading through technical documents from Cisco or attending webinars and conferences on the topic.

Once I have a thorough understanding of the current standards, I would then look into ways to incorporate them into our existing system. This could involve updating hardware and software components, as well as making changes to our network configuration. I would also take into account any potential risks associated with implementing these changes and make sure that they are addressed before proceeding. Finally, I would test the new system to make sure everything works correctly and document all changes made.”

12. Describe your experience with network topology design.

Network topology design is a key component of being a Cisco network engineer. The interviewer may ask this question to learn more about your experience with designing networks and how you approach the task. In your answer, describe your process for designing a network and highlight any specific skills or tools that helped you complete the task.

Example: “I have extensive experience in designing and implementing network topologies. I have worked on a variety of projects, ranging from small local area networks to large enterprise-wide networks. My expertise includes designing both physical and logical topologies for LANs, WANs, and wireless networks.

When it comes to network design, I always take into account the customer’s needs and requirements. I make sure that the network is designed with scalability and reliability in mind, while also taking into account any security or performance concerns. I am familiar with different routing protocols such as OSPF, EIGRP, BGP, and RIP, and can configure them according to best practices.

In addition, I have experience in troubleshooting complex network issues related to topology design. This includes identifying problems with the physical layout of the network, configuring routers and switches, and resolving connectivity issues. I am comfortable working with various monitoring tools to identify and resolve network issues quickly and efficiently.”

13. What makes you the best candidate for this position?

Employers ask this question to learn more about your qualifications and how you feel you are the best fit for their open position. When answering this question, it can be helpful to highlight a few of your strongest skills or experiences that relate to the job description.

Example: “I believe I am the best candidate for this position because of my extensive experience and expertise in Cisco networks. I have over 10 years of hands-on experience designing, implementing, and troubleshooting complex enterprise networks using a variety of Cisco technologies. My technical knowledge is up to date with the latest industry standards and trends, which allows me to quickly identify issues and develop solutions that are both cost-effective and reliable.

In addition to my technical skills, I also possess excellent communication and problem-solving abilities. I am able to effectively collaborate with other team members to ensure successful network deployments and troubleshoot any issues that may arise. I am highly organized and detail-oriented, allowing me to stay on top of tasks and deliver projects on time. Finally, I am passionate about networking and always strive to stay ahead of the curve by continuously learning new technologies and techniques.”

14. Which programming languages are you most familiar with and which do you prefer to use for network maintenance?

This question allows the interviewer to assess your technical knowledge and experience with programming languages. Your answer should include a list of languages you are familiar with, along with an explanation of why you prefer one over another.

Example: “I am most familiar with Python and Bash scripting languages. I prefer to use Python for network maintenance because of its flexibility and the wide range of libraries available. It is also a great language for automating tasks, which can save time and effort when maintaining large networks. I have used it extensively in my current role for creating scripts to automate routine tasks such as configuring routers, switches, firewalls, etc.

I also have experience using Ansible for network automation. This has allowed me to quickly deploy configurations across multiple devices at once and make sure they are all configured correctly. I find this to be an invaluable tool when managing complex networks.”

15. What do you think is the most challenging part of being a network engineer?

This question is an opportunity to show the interviewer that you are aware of the challenges in this role and how you plan to overcome them. You can answer by identifying a specific challenge, explaining why it’s challenging and describing your strategy for overcoming it.

Example: “The most challenging part of being a network engineer is staying up to date on the latest technology and trends. As new technologies emerge, it’s important for network engineers to be able to quickly understand how they work and how they can be used to improve existing networks or create new ones. This requires an understanding of not only the underlying technology but also its application in various scenarios. It also requires keeping abreast of industry news and developments so that one can anticipate potential problems before they arise.

I believe my experience as a Cisco Network Engineer has prepared me well for this challenge. I have been working with Cisco products for over five years now, and I am always eager to learn more about their newest offerings. I stay current by reading technical blogs, attending conferences, and participating in online forums. My expertise in Cisco networking solutions allows me to quickly assess any given situation and come up with creative solutions.”

16. How often do you update your knowledge of computer technology and networking trends?

This question can help the interviewer determine how much you value continuing your education and training. It is important to show that you are committed to staying up-to-date on new technology developments in computer networking.

Example: “I am constantly updating my knowledge of computer technology and networking trends. I stay up to date on the latest developments in the industry by reading trade publications, attending conferences, and participating in online forums. I also take advantage of any available training opportunities that are offered through Cisco or other vendors. This helps me keep abreast of new technologies and best practices for network engineering.

In addition, I have a strong background in troubleshooting complex networks and resolving issues quickly. I use this experience to help identify potential problems before they become major issues. By staying current with the latest advancements in the field, I can provide proactive solutions that will ensure optimal performance of the network.”

17. There is a bug in the code for a new software update that you need to deploy to all of the company’s computers. What is your process for testing and deploying the update?

This question is an opportunity to show your problem-solving skills and ability to work with a team. You can describe the steps you would take to test and deploy the update, including how you would communicate with other network engineers about the deployment.

Example: “When it comes to testing and deploying a new software update, I have a tried-and-true process that I use. First, I would thoroughly test the code on my own system to ensure that there are no bugs or issues with the code before deployment. Once I am confident that the code is ready for deployment, I would then create a plan for rolling out the update across all of the company’s computers. This plan would include steps such as creating backups of existing systems, scheduling downtime for maintenance, and ensuring that all users are aware of the changes. Finally, I would deploy the update in stages, starting with a small group of computers and gradually expanding until the entire network has been updated. Throughout this process, I would be monitoring the results closely to make sure that everything goes according to plan.”

18. What is the most complex networking problem you have ever solved?

This question can give the interviewer insight into your problem-solving skills and how you approach a challenge. Your answer should include details about the situation, what steps you took to solve it and the result of your actions.

Example: “The most complex networking problem I have ever solved was a routing issue that had been causing intermittent outages for several weeks. The root cause of the problem was hard to identify because it involved multiple routers, switches, and firewalls across two different sites.

To solve this problem, I first identified the affected devices by running network scans and analyzing packet captures. After isolating the source of the issue, I then worked with the vendors to troubleshoot the hardware components and determine if any firmware updates were needed. Finally, I configured the necessary routes and protocols on each device to ensure optimal performance.”

19. How do you stay organized when managing multiple projects at once?

This question can help the interviewer assess your time management skills and ability to prioritize tasks. Your answer should highlight how you stay organized with multiple projects, including how you manage your time and communicate with team members about deadlines.

Example: “Staying organized is essential when managing multiple projects at once. I have developed a few strategies to ensure that all of my projects are on track and running smoothly. First, I create an action plan for each project with clear goals and timelines. This allows me to easily keep track of progress and make sure deadlines are met. Second, I use project management software such as Microsoft Project or Trello to help organize tasks and prioritize them according to importance. Finally, I stay in constant communication with the team members involved in each project so that everyone is aware of their responsibilities and any changes that need to be made. By following these steps, I am able to effectively manage multiple projects at once without getting overwhelmed.”

20. If a user reports that their device isn’t connecting to the network, how would you troubleshoot this issue?

This question is a great way to test your problem-solving skills and ability to work with clients. Your answer should include the steps you would take to troubleshoot this issue, as well as how you would communicate with the user about what’s happening during the process.

Example: “If a user reports that their device isn’t connecting to the network, I would first ask them for more information about the issue. This includes what type of device they are using, if it is wired or wireless, and any error messages they may have received. Once I have this information, I can begin troubleshooting the issue.

I would start by checking the physical connection between the device and the router or switch. If the connection looks good, then I would check the IP address assigned to the device to make sure it is valid. If not, I would assign a new one.

Next, I would check the configuration of the router or switch to ensure that the correct ports and protocols are enabled for the device. Finally, I would run some basic diagnostic tests such as ping and traceroute to determine if there is an issue with the network itself.”

21. Describe your experience with virtualization and cloud-based technologies.

Cisco is a leader in networking technology, and the interviewer may ask you this question to see if your experience aligns with Cisco’s. If you have previous experience working with virtualization or cloud-based technologies, describe it in detail. If you don’t have any experience, explain that you’re eager to learn more about these technologies.

Example: “I have extensive experience with virtualization and cloud-based technologies. I have worked on projects involving the design, implementation, and maintenance of virtualized environments using VMware vSphere, Microsoft Hyper-V, and Citrix XenServer. I am also familiar with Amazon Web Services (AWS) and Azure for cloud-based solutions.

I have implemented a variety of virtualization solutions in both large and small enterprise networks. My experience includes setting up virtual machines, configuring storage and network resources, and managing user access. I have also designed and deployed high availability clusters to ensure maximum uptime and performance. In addition, I have created automation scripts to automate routine tasks such as patching, backups, and software deployments.”

22. What strategies do you use to ensure your networks are secure?

Cisco networks are often used to store sensitive information, so it’s important that they’re secure. Your answer should show the interviewer you know how to keep data safe and prevent cyber attacks. You can mention specific strategies or steps you use to ensure your network is secure.

Example: “When it comes to network security, I believe in taking a proactive approach. My first strategy is to stay up-to-date on the latest security threats and vulnerabilities. This includes reading industry news, attending conferences, and participating in online forums. I also use automated tools such as vulnerability scanners to detect any potential weaknesses in my networks.

Once I have identified any potential risks, I take steps to mitigate them. This could include patching software, implementing firewalls, or encrypting data. I also regularly review user access rights and permissions to ensure that only authorized personnel can access sensitive information. Finally, I conduct regular training sessions with users to make sure they understand their roles and responsibilities when it comes to network security.”

23. What methods do you use to optimize performance on large networks?

This question allows you to demonstrate your knowledge of Cisco’s network optimization tools. You can list the methods and explain how they work.

Example: “I have extensive experience optimizing performance on large networks. I use a combination of methods to ensure the best possible results. First, I start by conducting an assessment of the current network infrastructure and its configuration. This allows me to identify any potential bottlenecks or areas where improvements can be made.

Once I have identified any issues, I then look at ways to improve the overall performance of the network. This could include implementing QoS policies, segmenting traffic, or upgrading hardware components. I also make sure that all devices are configured correctly and that they are running the latest software versions. Finally, I monitor the network closely to detect any changes in usage patterns or other anomalies that might indicate a need for further optimization.”

24. Are there any areas of Cisco technology or related topics that you are particularly knowledgeable in?

This question is a great opportunity to show the interviewer that you are passionate about your work and have experience in areas of Cisco networking. You can use this question as an opportunity to discuss any projects or achievements related to Cisco technology.

Example: “Yes, I am very knowledgeable in Cisco technology and related topics. My experience includes working with a wide range of Cisco products such as routers, switches, firewalls, wireless access points, and security appliances. I have also worked extensively with network protocols such as TCP/IP, OSPF, BGP, EIGRP, and IPSec.

I am well-versed in the design and implementation of complex networks, including WANs and LANs. I have extensive experience troubleshooting and resolving networking issues, as well as configuring and managing Cisco devices for optimal performance. In addition, I have experience designing secure networks that meet industry standards and best practices.”

25. How do you handle difficult situations such as dealing with system outages or security threats?

This question can help the interviewer assess your problem-solving skills and ability to work under pressure. Your answer should highlight your analytical, interpersonal and leadership skills.

Example: “When dealing with system outages or security threats, I approach the situation with a calm and methodical attitude. First, I assess the current state of the network and identify any potential issues that could be causing the outage or threat. Then, I work to quickly isolate the problem by troubleshooting the affected systems and networks. Once the issue is identified, I take steps to mitigate it as quickly as possible. This often involves implementing temporary fixes while working on more permanent solutions. Finally, I document all changes made so that they can be tracked and referenced in the future.”