Here's how you can ace technical interview questions in the computer networking field.

The best way to ace technical interviews is to tell a story to illustrate the question being asked. For example, if someone asks you the difference between a threat, a risk and a vulnerability, you could say something like - my neighbour smokes and flicks his cigarette butts into dry grass (threat). The vulnerability is the dry grass. The risk is he could burn my house down. If the question is, "what's the difference between TCP and UDP?". Tell the old joke - "I sometimes tell a UDP joke and no one gets it. Everyone gets my TCP joke". Theory does not apply in real life. Application of the theory through examples does.

Irrespective of any field and especially in networking strong basics build the foundations very strong. Despite of lots advancement in technologies like SDN in Enterprise, Campus or in DC, Basics of networking remain the same. Deep understanding of basics helps to ace the interview and understanding the packet flows. I have seen people with multi years of experience struggles in basic packet flows. So start with strong basics and then add different layers on top of it.

The OSI model with all its flaws is still the most used model to describe how a packet flows through the network. In an interview there's often not enough time to cover more than the basics and some projects the candidate has worked on. Do they have an understanding of IP addressing? Do they understand what is required to communicate? How does a L2 device forward a frame? How does a L3 device forward a packet? What happens when the packet goes to the internet? Why do we need DNS? Knowing the basics is critical to be able to properly understand more complex topics.

In networking, understanding packet flows is one of the most important skills. This means you need to have knowledge of the different protocols involved. A host needs an IP so it's important to understand DHCP and how it can break. You should have at least a basic understanding of DNS. What types of servers are there? How do they differ? How is load sharing/load balancing achieved with DNS? It's also important to understand the apps, where many of them use HTTP. Get familiar with TLS and certificates as nearly all communication is encrypted.

While troubleshooting to some degree is a skill in itself, it's also critical for getting to know a protocol or feature at depth. It's not until you've performed labs and dealt with troubleshooting that you can really evaluate how well you know something. I always recommend people to build labs and break them. What went wrong? How do you diagnose it? How do you fix it? What does the packet capture show you? You should apply a structured methodology to your troubleshooting. Do you start at the top or bottom layer? Or in the middle? Combine it with experience and intuition to find the problem as quickly as possible.

Network design and architecture are what I would consider timeless skills. They will make you stand out and they will provide job security as tools like automation and AI can't replace what a good architect does such as talking to the business, translating between business and tech, and producing high quality documentation. Discussing design in an interview can be a great way of showing the experience you've gathered and how you have transitioned from implementation to design. What are some projects you worked on? What were the requirements? Why did you choose protocol X over protocol Y? These can be great discussions as long as the interviewer has an open mind.

The days of silos where you could focus on one thing and one thing only are over. Security is not only for the people in cyber security or network security, it's the responsibility of all the teams involved. Do you have an understanding of segmentation? Lateral movement? Firewalls? VPNs? Cloud security and SASE? IoT? You can't go to depth in all topics, but you need to build a basic understanding of security. It should be top of mind when creating designs and when implementing the network. Where do you put guest users? How do you authenticate your employees to access the network? If you can have a discussion around security that will showcase your breadth.

Indeed staying relevant with latest technologies trend is similar to survival for the fittest theory, Because with the pace technologies are evolving and if we don’t stay updated we will loose our relevance in the market. So IMHO, Keep updating the knowledge in terms of reading the blogs, watch the webinars organise by OEM, youtube videos by technologist and at last paid courses if someone can afford or company sponsored.

Over the course of years, I've been thru a fair few rounds myself. Bombed a few too ??. Often times, I think it helps to take a step back and reflect on the obvious mistakes that were made, and if there was something that could have been put forward in a better manner. I always have belief in the quote, if you want to move forward, you can't keep looking back. Trust the CV and believe in yourself and your skills. Most importantly, it is OK to not know everything, and I personally think it's much better to say Sorry I don't know, rather than being someone on the fake it till you make it bandwagon. If you train with weights (like me) to cool down after an interview, just hit two more reps for King Ronnie in each set. Light Weight ????..!