CDK Global India Telecom Analyst Interview: Rounds, Questions and Preparation

What the job involves

A Telecom Analyst supports the design, operation, and optimisation of voice, data, and unified communication networks for an enterprise or its clients. Day to day work includes monitoring network performance, analysing call and traffic data, troubleshooting connectivity issues, and preparing reports on cost, capacity, and service quality. In a growing IT services or product company, the role often sits between telecom vendors, internal IT teams, and business users.

Role and Telecom Fundamentals

1. 1

   What is the difference between circuit-switched and packet-switched networks in telecom?

   Explain that circuit switching reserves a dedicated path for the call, while packet switching breaks data into packets routed independently. Give one example of each, such as traditional PSTN versus VoIP.

2. 2

   Walk me through what happens when you make a VoIP call from your laptop to a mobile number.

   Cover signalling via SIP, media encoding with a codec, RTP packet flow, and the role of a gateway or SBC that connects the IP network to the PSTN or mobile network.

3. 3

   What are the key telecom KPIs you would track for a voice service?

   Mention ASR, ACD, MOS, jitter, packet loss, and call setup success rate. Briefly say what each indicates about service quality.

4. 4

   What is number portability and why does it matter for telecom operators in India?

   Define mobile number portability as the ability to keep the same number when changing operators. Mention that it increases competition and requires accurate routing and database updates.

Networking and Technical Knowledge

1. 5

   Explain the OSI model layers and give one telecom example for each layer.

   List all seven layers briefly. For telecom, link physical cables and radio to Layer 1, IP addressing to Layer 3, SIP to Layer 5, and voice codecs or RTP to Layer 7 or transport depending on how you classify them.

2. 6

   What is SIP and how does it differ from RTP?

   SIP is a signalling protocol for setting up, modifying, and tearing down sessions. RTP carries the actual media such as voice packets. SIP does not carry voice itself.

3. 7

   How would you use ping, traceroute, and a packet analyser to troubleshoot a network issue?

   Ping checks reachability and round-trip time, traceroute shows the path and where delays occur, and a packet analyser like Wireshark reveals protocol-level errors or dropped packets. Describe a simple sequence of using them.

4. 8

   What is the difference between a public and a private IP address in an enterprise telecom setup?

   Public IPs are routable on the internet, private IPs are used inside internal networks and need NAT for internet access. Mention that enterprises often use private addressing with NAT for voice and data traffic.

Practical Scenarios and Problem Solving

1. 9

   Users at one branch report choppy voice calls while other branches are fine. How would you investigate?

   Start by checking local internet bandwidth, jitter, and packet loss. Compare with a working branch, inspect router or firewall QoS settings, and check whether the issue is on the LAN, WAN, or service provider side.

2. 10

   A client complains that international calls are failing but domestic calls work. What could be the cause?

   Consider carrier routing rules, international dialling permissions, blocked prefixes, or a failed SIP trunk to the international gateway. Suggest checking call logs and testing with a known working international number.

3. 11

   You notice a sudden spike in call drops on a VoIP platform. What data would you pull first?

   Pull call detail records, gateway or SBC logs, CPU and memory usage on voice servers, and network latency graphs. Look for a common time, route, or codec pattern.

4. 12

   How would you explain a technical telecom issue to a non-technical business user?

   Use an analogy such as a highway with traffic or a phone line with static. Avoid jargon, state the impact clearly, and give a simple timeline for the fix.

Behavioural and HR Questions

1. 13

   Telecom support often involves shifts or on-call duty. How do you feel about that?

   Show willingness and awareness. Mention that you understand network issues can happen anytime and that you are open to rotational shifts if needed.

2. 14

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

   Use a specific example. Describe the topic, the resources you used, the timeline, and the result. Highlight your method for learning under pressure.

3. 15

   Describe a situation where you had to explain something complex to a friend or teammate who did not understand it.

   Focus on patience and clarity. Explain how you broke the topic into smaller parts and checked for understanding, which is key for client-facing telecom roles.

4. 16

   Why do you want to work as a Telecom Analyst in the telecom and internet sector?

   Connect your interest to the growth of Indian telecom, VoIP, and cloud communications. Mention that you enjoy troubleshooting and want to build expertise in network performance and service quality.