10 Routing Interview Questions (With Sample Answers)

Updated 22 June 2023

Routing protocols are a set of rules that govern the transmission of data in any network setup. Understanding the fundamentals and technicalities of implementing the right routing protocol is necessary to a network engineer or administrator role. Learning about the various questions that hiring managers may ask to test your knowledge about routing can help you prepare for the interview. In this article, we discuss 10 routing interview questions with sample answers to help you prepare for your next interview.

10 Routing Interview Questions

Hiring managers may ask several routing interview questions to test your fundamental, technical and practical knowledge about this topic. Here are a few questions with sample answers to help you prepare for your interview:

1. Can you share your knowledge of routing protocols?

Routing protocols are fundamental to any network engineer or administrator. Hiring managers may ask this question to understand if you have a clear knowledge of the concept and its significance. Provide a concise answer highlighting the different classifications of routing protocols.

Example answer: Routing protocols and be categorised into three related pairings. These include distance vector and link state protocols, interior gateway and exterior gateway protocols and classful and classless protocols. Distance vector protocols measure the distance it takes for data to reach its destination within an application. Similarly, the link state shares information by calculating the speed and cost of a potential path. Interior gateway protocols exchange information within a single autonomous system, whereas exterior gateway protocols perform this function between multiple systems. Lastly, classful protocols route without subnet mask information, while classless route updates with devices in different networks.

2. Why are there multiple routing protocols?

Understanding how routing protocols function is necessary to the role of a network engineer. Hiring managers may ask this question to evaluate your knowledge of data centres, routing protocols and how the ecosystem functions. Keep the answer brief and discuss the use of multiple routing protocols.

Example answer: In any given data centre environment, multiple routing protocols have various roles. They ensure that data flows through the ecosystem even if one routing protocol fails. Additionally, they ensure that the diverse types of traffic entering the system receive different service levels.

3. Can you explain convergence time?

In setting up any network, understanding its convergence time helps optimise the system. Employers may ask this question to assess how well you choose the right routing protocol to make a system fast. Keep the answer brief and discuss the convergence time of different routing protocols.

Example answer: Routers share the same topological information about the internetwork in which they operate. Convergence time is a measure of how quickly routers may reach this equilibrium. It is an important performance indicator for routing protocols, as it indicates a reliable and fast system. For example, Open Shortest Path First or OSPF, is a routing protocol with one of the shortest convergence times.

4. What is OSPF?

This question helps hiring managers test your fundamental knowledge about networking and routing protocols. Explain the meaning of OSPF, how it differs from other routing protocols and discuss its advantage. Keep the answer brief.

Example answer: OSPF is a routing protocol that divides an autonomous system into multiple areas to reduce routing updates in the network. This helps speed convergence in routing as it calculates the shortest time when a network topology changes. It also helps reduce overhead costs and is suitable for a large heterogeneous internetwork. OSPF also helps restrict network instability to single area in the entire network.

5. What is the #no auto-summary command in EIGRP?

Each network may have different requirements and this question helps hiring managers understand how well you work on managing configurations. To answer this question, you can explain the meaning of EIGRP while sharing the pros and cons of auto-summary. You can also summarise the process of implementing the command and how it benefits the network and organisation.

Example answer: Enhanced interior gateway routing protocol or EIGRP, helps automate routing decisions and configurations on a computer network. There is a default automatic route summarisation feature on EIGRP. It helps aggregate the routes to classful addresses during routing updates. It often causes issues with discontinuous subnetworks. You can use the command #no auto-summary to avoid hassles in the network. The command allows a network engineer to switch off the default automatic route summarisation.

6. What is bandwidth?

This question aims to test your fundamental skills and knowledge. As a network engineer or administrator, it is necessary to understand the right bandwidth to meet organisational requirements. Employers may ask this foundational question to ensure you are aware of the basics of routing protocols.

Example answer: A network bandwidth refers to the maximum capacity of a wired or wireless communication link to transmit data in a given time. It is typically the number of bits, kilobits, megabits or gigabits sent in one second. Bandwidth is necessary to determine the quality and speed of a network. The higher the capacity or bandwidth, the more data a network can handle or transmit per second.

7. What is a null interface?

Network security is necessary to the role of a network engineer. This question helps hiring managers assess your technical knowledge of network security fundamentals. Keep the answer brief and discuss the importance of the null interface.

Example answer: A null interface is like a black hole where all traffic gets discarded. It helps prevent the server from receiving or sending data over the internet. It is often active to detect distributed denial-of-service attacks.

8. Where do you use the next hop router?

This question tests your technical knowledge of how data transmits in the network. Hiring managers may ask this question to evaluate your expertise on next hop routers and their functions. Keep your answer short and discuss its applications.

Example answer: The source router uses the next hop router to help forward packets to their destination networks. The next hop router gets connected directly or indirectly and is reachable through one or more intermediate hops. It is typically within an autonomous system to forward traffic to different domains.

9. What are iBGP sessions and can you configure them?

This question aims to evaluate your advanced networking knowledge. Hiring managers may ask this question to assess your problem-solving skills and ability to implement complex network requirements. Keep the answer brief and discuss the necessary steps to configure the sessions.

Example answer: An Internal Border Gateway Protocol or iBGP, session is one where two BGP routers belong to the same autonomous system. They are not directly connected and get configured using a BGP command on port 179. Users can encrypt these sessions utilising Transport Layer Security or Internet Protocol Security.

10. How can you configure the router to prefer OSPF over the EIGRP route?

This question aims to evaluate your technical knowledge and ability to apply it. Hiring managers may ask this question to assess your ability to resolve issues in the network and implement systems that benefit the organisation. Keep the answer brief and discuss the necessary steps you can take to configure the router.

Example answer: A simple command in the global configuration mode of the router helps it prefer OSPF over EIGRP. While configuring, it is necessary to input the administrative distance for EIGRP to a higher value than OSPF. The command is usually Router(config)# distance eigrp.

10 Routing Interview Questions (With Sample Answers)