People seem to dread interviews, but it's an ideal time for you to show what you know and learn more about the company.

Remember that you are not likely to be able to answer every question perfectly, and never bluff your way through an answer. Tell the interviewers you aren't sure but will research it after the interview is over. They will probably appreciate your honesty!

We cover interview preparation in our video training course on how to land your first IT job, but of course, you need to research the role you are applying for and what is expected so you can prepare as well as possible.

Here are five of the most commonly asked questions for junior network engineers, but of course, anything from the CompTIA Network+ would be considered fair game.

What are the OSI layers, and what is their function?

The OSI (Open Systems Interconnection) model is a framework for understanding how data is transmitted over a network. The OSI layers are:

• Layer 1: Physical
• Layer 2: Data Link
• Layer 3: Network
• Layer 4: Transport
• Layer 5: Session
• Layer 6: Presentation
• Layer 7: Application

What is your experience with routing protocols such as OSPF and BGP?

Answering this question will depend on the person's specific experience with these protocols. They could discuss configuration, troubleshooting, and any experiences working with OSPF and BGP in different network environments.

Can you explain VLANs and how they work?

A VLAN (virtual LAN) is a logical subnetwork that can segment a physical network into multiple broadcast domains. VLANs can be used to segment a network by department, application, or any other logical grouping of network devices. VLANs use tagging to identify packets that belong to a specific VLAN, allowing them to be passed only to devices that are members of that VLAN.

What is the purpose of a firewall, and how do you configure it?

A firewall is a security system that controls the incoming and outgoing network traffic based on predetermined security rules and policies. Firewalls can be implemented using hardware, software, or a combination of both. When configuring a firewall, an individual would need to set up rules that specify which traffic is allowed and which is denied.

What do you know about Quality of Service (QoS)?

Quality of Service (QoS) is a set of technologies and techniques used to manage network resources and prioritize certain types of network traffic over others. QoS can help ensure that critical network traffic, such as voice and video, is given priority over less critical traffic, such as file transfers and email.

It's important to read the job post because if they mention a specific technology or protocol, you will be asked about it. You may well be asked about IP subnetting in detail, even for junior roles. This book will help you.