Microsoft Azure India Core Network Specialist Interview: Rounds, Questions and Preparation

What the job involves

A Core Network Specialist in telecom and internet keeps the high-capacity backbone that carries subscriber and cloud traffic running. Day to day you monitor links, troubleshoot routing and switching issues, plan capacity, and work with field and vendor teams to restore or improve service. In a cloud-focused company, you may also connect data centres and peering points to carrier networks.

Role and technical knowledge

1. 1

   Explain the difference between a router and a switch, and where each fits in a telecom backbone.

   Cover OSI layer, forwarding decisions, and typical deployment: switches for high-density LAN or aggregation, routers for interconnecting sites and running BGP or OSPF.

2. 2

   How does BGP help internet traffic find its way between autonomous systems?

   Mention path-vector behaviour, AS numbers, peering and transit, and why BGP is preferred over interior protocols for inter-domain routing.

3. 3

   What happens step by step when you type a website address and press Enter, from a network perspective?

   Walk through DNS resolution, TCP handshake, HTTP request, routing, and response. Show awareness of latency, caching, and the role of the core network.

4. 4

   What is subnetting and why does a core network engineer need to be comfortable with it?

   Explain CIDR, subnet masks, and address planning. Give a small example of dividing a block for point-to-point links and loopbacks.

Practical scenarios

1. 5

   A core link between two cities shows high packet loss and latency spikes. How would you troubleshoot it?

   Start with monitoring dashboards and interface counters, check for errors or discards, run ping and traceroute, inspect routing changes, and involve field teams if it is a physical issue.

2. 6

   You need to add a new VLAN for a customer on an existing switch. What steps and checks do you follow?

   Cover VLAN creation, trunk and access port configuration, spanning-tree considerations, and verification with show commands and a test host.

3. 7

   During a maintenance window, a routing change causes a brief outage. What do you do next?

   Focus on rollback plan, communication with stakeholders, capturing logs, and writing a clear post-incident note with lessons learned.

4. 8

   How would you use packet capture to prove whether a problem is in the network or in an application?

   Mention tools like tcpdump or Wireshark, filtering by host and port, checking TCP flags, retransmissions, and comparing both ends of the connection.

Behavioural and situational

1. 9

   Tell me about a time you had to learn a technical topic quickly for a project or exam.

   Use a clear situation-action-result structure. Show how you found resources, practised, and applied the learning under a deadline.

2. 10

   Core network teams often work in shifts and handle escalations. How do you stay calm and organised under pressure?

   Give a real example of prioritising tasks, following runbooks, and asking for help when needed. Mention clear communication with seniors.

3. 11

   Describe a time you disagreed with a teammate on a technical approach. How did you resolve it?

   Show that you listened, used data or documentation to compare options, and accepted the team decision even if it was not your first choice.

4. 12

   Why do you want to work in telecom and core networking rather than other software roles?

   Connect your interest to the scale and critical nature of backbone networks, your coursework or projects, and a willingness to learn on the job.

HR and background

1. 13

   Are you comfortable with 24x7 shift work and on-call rotations that core network operations sometimes require?

   Answer honestly and show awareness of what on-call means. If you have constraints, state them politely and focus on your flexibility.

2. 14

   Walk me through your final-year project or any networking lab work you have done.

   Keep it short and technical: what you built, which protocols or tools you used, and what you learned about troubleshooting or design.

3. 15

   Where do you see yourself in three years in a core network role?

   Show a realistic path: deeper protocol expertise, certifications, automation skills, or leading small incident teams. Avoid vague answers.

4. 16

   Do you have any certifications or plans to pursue one, such as CCNA or JNCIA?

   Mention any completed or planned certification and what you are doing to prepare. If none, explain how you are building equivalent knowledge through labs or courses.