WLAN Designer Interview Questions & Answers

1

What are the different types of network cables?

Reference answer

Common network cables include: - UTP (Unshielded Twisted Pair): The most common type, consisting of two insulated wires twisted together to reduce interference. - STP (Shielded Twisted Pair): Similar to UTP, but with an additional metallic shield to further reduce interference. - Coaxial Cable: Consists of a central conductor surrounded by insulation and a metallic shield. Used for older networks and video transmission. - Fiber Optic Cable: Transmits data using light pulses through thin glass fibers, offering high bandwidth and immunity to interference.

2

Supervisor interview questions with STAR-style answer blueprints, strong vs weak examples, red flags, and first-time manager framing for candidates and hiring.

Reference answer

Interview questions for human resources manager roles, with strong sample answers, what each question is really testing, and how to tailor responses if youre.

3

What is the difference between WEP, WPA, and WPA2?

Reference answer

WEP uses static keys and RC4 encryption, easily hacked. WPA uses TKIP with RC4 encryption, improving security over WEP. WPA2 uses AES encryption, which is the most secure up-to-date algorithm.

4

What is a network security incident response plan?

Reference answer

A network security incident response plan is a documented process for responding to security incidents. It outlines steps for identifying, containing, investigating, and recovering from security breaches, minimizing damage and restoring network operations.

5

What relevant network engineering qualifications do you have?

Reference answer

Here you can list any qualifications or certifications youâve gained on your network engineering journey, whether through university degrees, network engineering courses or an apprenticeship course youâve completed. Although you may put all this down on your CV, this network engineer question allows you to expand on the qualifications youâve achieved, why you enrolled on these courses, and what you learned.

6

Can you explain the significance of phase noise in an RF system and how it can be mitigated?

Reference answer

Seeking detailed understanding of phase noise, its sources, its impact on system performance, and common strategies employed to reduce phase noise in RF systems.

7

How do you configure high availability on a WLC?

Reference answer

To configure high availability (HA) on a Wireless LAN Controller: - Configure primary and secondary (standby) WLCs in HA mode. - Ensure APs can failover to standby WLC automatically. - Test failover scenarios to confirm seamless client connectivity. - Use redundancy for critical sites to prevent downtime.

8

What is a VPN, and how does it work?

Reference answer

A VPN (Virtual Private Network) creates a secure, encrypted connection between a device and a remote server, allowing users to access the internet privately. It hides the user's IP address and encrypts data, protecting it from hackers and surveillance. VPNs are commonly used for secure remote access, bypassing geo-restrictions, and maintaining privacy on public Wi-Fi networks.

9

How would you design a network for a new office, considering security, scalability, and budget?

Reference answer

Designing a network for a new office starts with understanding the business requirements: number of users, applications used, and growth projections. Security is paramount; I'd implement a firewall, VLANs to segment traffic, and strong password policies. A guest Wi-Fi network with its own firewall rules is crucial. We'll also assess needs for VPN access for remote workers. For scalability, I would choose network devices that support future expansion and consider cloud-based solutions where appropriate. Budget is a key constraint, so I'd evaluate cost-effective solutions without compromising security or performance. A phased rollout, starting with essential services and gradually adding features, can help manage costs. Consider open-source solutions where viable alternatives exist. Consider the location of servers or if they can be cloud-based.

10

What is NAT?

Reference answer

NAT stands for Network Address Translation. The process of NAT involves converting a specific range of private IP addresses to a single public IP address linked to a gateway device. The network address translation process allows a single device to act as an intermediary or agent between a private, localized network and a public network, such as the Internet. The main focus of NAT is to conserve public IP addresses.

11

What is QoS (Quality of Service)?

Reference answer

Quality of Service (QoS) is a networking feature that gives important network traffic higher priority than less important traffic. In simple words, it controls which data should move first in the network when the network gets busy. A network carries many types of data: - Video calls - Voice calls - YouTube Videos - File Downloads - Emails - Online games, etc. But not all traffic is equally important. Without QoS, all the traffic is treated the same way, which can cause: - Voice breaking - Video buffering - Slow application performance - Lag during meetings, etc. QoS solves these problems by giving priority to important traffic.

12

What is SD-WAN?

Reference answer

SD-WAN stands for Software-Defined Wide Area Network. It is a solution based on SDN architecture for simplifying WAN management. It separates the control and data planes to optimize application performance and reduce costs.

13

What is the Doppler effect in wireless communication?

Reference answer

The Doppler effect is the change in frequency of a signal due to the relative motion between the transmitter and the receiver. It can cause frequency shifts in wireless communication, especially in mobile environments, affecting signal quality.

14

What are clients and servers in a network?

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The client is the component responsible for initiating communication and requesting a network service, such as retrieving a web page, transferring a file, or transmitting an email. The server is the component responsible for responding to client requests and delivering the requested service, such as transmitting a webpage, file, or email. Computer application uses the client-server model.

15

What factors do you consider when designing a data center network?

Reference answer

When designing a data center network, skilled network engineers would focus on factors like scalability, redundancy, and security, to ensure the network can handle increasing data loads and expand as needed. They'd also implement redundant paths and devices to maintain availability and reliability and consider implementing strong security measures, including firewalls, intrusion detection systems, and secure access controls.

16

How would you provide user-based authentication on a wireless network?

Reference answer

User-based authentication on a wireless network can be provided using 802.1X with a RADIUS server. This requires a wireless controller or access points that support 802.1X, a RADIUS server for credential verification (e.g., Active Directory), and client devices configured for WPA2-Enterprise or WPA3-Enterprise authentication.

17

What tools are used to monitor performance?

Reference answer

Common tools used to monitor and analyze wireless network performance include: - Cisco DNA Center: Provides real-time monitoring and configuration. - Wireshark: Captures network traffic to analyze issues. - Ekahau: Conducts site surveys and visualizes coverage. - AirMagnet: Troubleshoots connectivity issues and RF interference.

18

What are the basic parameters to configure on a wireless access point?

Reference answer

Parameters Include: SSID, RF, Channel authentication method.

19

What is a packet in networking?

Reference answer

Imagine sending a package through the mail. In networking, a 'packet' is like that package. It's a small bundle of data that's being sent across a network. Just like a physical package needs an address to arrive at the right place, a packet contains information like the sender's and receiver's IP addresses (like a postal address) and other control information. The actual data being transmitted is like the contents of the package. Similar to how a large item is broken down into smaller boxes for easier shipping, large files or data streams are split into multiple packets. Each packet is then sent independently and reassembled at the destination. This allows for efficient and reliable data transfer, especially across networks with varying capacities or potential disruptions.

20

How do you approach capacity planning for a network?

Reference answer

I start by analyzing current network usage and growth trends to forecast future requirements. By implementing scalable solutions and regularly reviewing capacity, I ensure the network can handle increased traffic and evolving business needs.

21

What is the OSI model, and why is it important?

Reference answer

The OSI (Open Systems Interconnection) model is a seven-layer framework that explains how network devices communicate. The layers are: - Physical: Handles physical connections (cables, signals). - Data Link: Manages data transfer between directly connected devices. - Network: Determines the best path for data (IP addressing, routing). - Transport: Ensures data is sent reliably (TCP, UDP). - Session: Manages communication sessions between applications. - Presentation: Translates data for compatibility (encryption, compression). - Application: Interfaces with user applications (web browsers, emails). Understanding the OSI model helps in diagnosing and fixing network issues.

22

What is port forwarding and when might you need it?

Reference answer

Port forwarding allows you to redirect network traffic from one port number on a network device (like a router) to another port number on a different device within the same network, or even to a different port on the same device. It's like having a receptionist at your router who knows where to send incoming calls (network requests). You might need to configure port forwarding to: host a game server from your home network, allow remote desktop access to a computer inside your network, set up a web server accessible from the internet, or access a security camera system remotely.

23

What is the OSI model and what are its seven layers?

Reference answer

The OSI model, or Open Systems Interconnection model, is a conceptual framework used to understand how different network protocols interact and work together to provide network services. The model is divided into seven layers starting from physical to application. At the bottom, we have the Physical layer (Layer 1), which encompasses the physical equipment involved in data transmission, such as cabling and connections. Above this is the Data Link layer (Layer 2), which handles error-free transmission of frames from one node to another. Next, we have the Network layer (Layer 3), responsible for data routing through different networks. The Transport layer (Layer 4) controls the reliability of a given link through flow control, segmentation/desegmentation, and error control. Session layer (Layer 5) manages sessions between applications. Presentation layer (Layer 6) handles syntax and semantics of data to be sent over a network. And finally, the Application layer (Layer 7) facilitates interactions between networked applications and the user. So, basically, data starts at the top (application layer) and works its way down through the layers adding extra bits of information, like source and destination addresses, as it goes, before eventually being sent across the network at the physical layer.

24

What is Wi-Fi and what is WiMAX?

Reference answer

Wi-Fi: Wireless Fidelity, a technology that uses radio waves for high-speed network connectivity based on IEEE 802.11 standards. Devices include PCs, laptops, video game consoles, phones, tablets, smart TVs, and more. WiMAX: Worldwide Interoperability for Microwave Access, referenced by IEEE 802.16, commonly termed 4G. It provides wide area network access and uses OFDM modulation.

25

The network becomes very slow during office hours. How would you identify the problem?

Reference answer

You should first check these things: - Bandwidth utilization - Broadcast storms - Duplex mismatch - High CPU usage on network devices - Excessive downloads or streaming - Malware or abnormal traffic You can use tools such as: - Wireshark - SNMP monitoring - NetFlow - Interface statistics on switches/routers You should also check: " show interfaces show processes cpu"

26

What are the OSI layers?

Reference answer

Here is another more tech-focused question you may be asked during your interview. As part of your network engineer interview preparation, hereâs how you can answer this question in a concise way that demonstrates your knowledge. âThe OSI model consists of seven layers: - Data link layer - Network layer - Presentation layer - Transport layer - Session layer - Physical layer - Application layer.â

27

What is interference in wireless communication?

Reference answer

Interference is the unwanted disruption of a signal by other signals, which can degrade communication quality. It can be caused by overlapping frequency channels, other wireless devices, or environmental factors.

28

How would you describe what anonymous FTP is?

Reference answer

Our final type of more technical network engineer interview question you could be asked can be answered straightforwardly, allowing the interviewer to evaluate your network engineering expertise. Hereâs how weâd advise answering technical types of network engineer interview questions like this: âAnonymous FTP provides a method for granting users access to files on public servers. Those permitted to access data from these servers can do so without the need for personal identification, but instead theyâll log in as anonymous guests.â

29

What role does monitoring and analytics play in the lifecycle management of enterprise networks?

Reference answer

Monitoring and analytics provide critical visibility into network performance, security posture, and potential issues. They enable proactive management, facilitate capacity planning, ensure compliance, and support continuous improvement throughout the network lifecycle.

30

What role does an RF engineer play in conducting environmental impact assessments for wireless infrastructure deployment, and how is this related to regulatory compliance?

Reference answer

This question measures the candidate's ability to understand the broader implications of RF engineering projects, including environmental concerns and how they align with regulatory compliance.

31

What project management methodologies are you familiar with, and which have you applied in the field of RF Engineering?

Reference answer

Candidate should show knowledge of various project management methodologies (like Agile, Waterfall, Scrum) and provide examples of how they've tailored these methodologies to suit RF Engineering projects.

32

What are your preferred tools for WarDriving?

Reference answer

Preferred tools for WarDriving are as follows:- a) Kismet- Kismet is a 802.11b wireless network sniffer. It is capable of sniffing using almost any wireless card supported in Linux. b) Airsnort- is one of the first tools to come out discovering insecurity of wireless network. AirSnort is a wireless LAN (WLAN) tool which cracks encryption keys on 802.11b WEP networks. AirSnort operates by passively monitoring transmissions, computing the encryption key when enough packets have been gathered. c) WEPCrack is Perl based tool. WEPCrack is a tool that cracks 802.11 WEP encryption keys using the latest discovered weakness of RC4 key scheduling. d) WaveStumbler is console based 802.11 network mapper for Linux. It reports the basic AP stuff like channel, WEP, ESSID, MAC etc. e) Aircrack yet another WEP cracking tool for Linux courtesy by divine.

33

How does a Layer 2 switch forward data?

Reference answer

A Layer 2 switch operates at the data link layer of the OSI model, where it uses MAC addresses to forward data frames. It learns and maintains a MAC address table by inspecting incoming frames, associating each MAC address with a specific port. When a frame arrives, the switch checks the destination MAC address and forwards it to the corresponding port, ensuring efficient and accurate delivery within a local network.

34

What is DNS and why is it crucial?

Reference answer

DNS, or Domain Name System, acts like a phonebook for the internet. It translates human-readable domain names (like google.com) into IP addresses (like 142.250.185.142), which computers use to identify each other on the network. Without DNS, we'd have to remember and type in these complex IP addresses every time we wanted to visit a website. DNS is crucial because it makes the internet user-friendly. It allows us to use memorable names instead of cumbersome numbers. Furthermore, DNS facilitates changes to IP addresses without affecting the user experience; a website can change its IP address, and DNS will update the mapping, so users continue to access it using the same domain name.

35

What kind of error is undetectable by the checksum?

Reference answer

In checksum, multiple-bit errors can not be undetectable.

36

What is the difference between 2.4 GHz and 5 GHz Wi-Fi frequencies?

Reference answer

The 2.4 GHz Wi-Fi frequency offers a broader range and better penetration through walls and obstacles but is more susceptible to interference from devices like microwaves and cordless phones. The 5 GHz frequency provides higher data rates and reduced interference, making it ideal for high-bandwidth activities like streaming and gaming but has a shorter range and less effective penetration through obstacles.

37

What are the different types of network security audits?

Reference answer

Different types of network security audits include: - Vulnerability Scan: Identifies security weaknesses and vulnerabilities in network devices and systems. - Penetration Testing: Simulates real-world attacks to assess the effectiveness of security controls and identify exploitable vulnerabilities. - Compliance Audit: Verifies adherence to security standards, regulations, and best practices. - Internal Audit: Assesses the effectiveness of internal security policies, procedures, and controls.

38

How would you diagnose a slow network performance issue affecting multiple users?

Reference answer

To diagnose a slow network performance issue affecting multiple users, I'd start by gathering information: How many users are affected? When did the issue start? What applications are slow? Then, I'd check the basics: Isolate the problem (is it specific to a subnet or application?), examine network device status (routers, switches, firewalls), and monitor network utilization (bandwidth usage, packet loss, latency) using tools like ping, traceroute, iPerf, and network monitoring software. Analyzing these metrics will help pinpoint the bottleneck. Next, I'd investigate potential causes: saturated network links, faulty network hardware, DNS resolution issues, application server overload, or even a malware infection. I'd prioritize based on the data gathered, focusing on the most likely culprits first. For example, high latency might indicate a WAN link issue, while high CPU usage on a server might suggest an application problem. Corrective actions might involve upgrading network hardware, optimizing application configurations, or implementing traffic shaping policies.

39

Describe a time when you dealt with a mismatched impedance in an RF system. How did you resolve it?

Reference answer

The candidate should provide a detailed account of a practical situation where they encountered impedance mismatch, the techniques they used to diagnose the issue, and the steps taken to achieve impedance matching.

40

How many (max) mac addresses are present in a 802.11 header

Reference answer

Four - Sender Address (SA), Transmitter address (TA), Destination address (DA) and Receiver address (RA)

41

A conflict interview question is easier to answer when you know how to pick the right story, shape it with STAR, and adjust it for entry-level, mid-level, or.

Reference answer

How do you handle stress interview answers that actually sound like you? Use these persona-based scripts for students, career switchers, returning applicants.

42

A new Business partnership has been agreed between 2 organization A and B respectively. Business Partner A needs to access some services/ applications of Organization B via a point to point link. Where should the links to be terminated considering the secured flow of traffic across both?

Reference answer

The links should be terminated in the DMZ (Demilitarized Zone) of each organization's network. This ensures that traffic from Business Partner A is isolated from Organization B's internal LAN, with firewalls enforcing access control policies to allow only specific services or applications.

43

What is Wi-Fi design?

Reference answer

Wi-Fi design is the process of taking your business' requirements for wireless connectivity and turning them into a high-performing and reliable Wi-Fi network. It's the translation of your business needs — how many devices need Wi-Fi (capacity) and where they need it (coverage) — into a deployment plan detailing how many access points you'll need, where they need to be installed, and how they should be configured in order to satisfy the demands of your users.

44

How do you configure AP failover in HA scenarios?

Reference answer

To configure AP failover in high-availability scenarios, enable HA mode on both the primary and secondary WLCs and ensure APs can reach both controllers via IP. Configure AP fallback options so they can connect to the secondary WLC if the primary fails, and test failover scenarios in a lab environment before deploying to production to ensure seamless client connectivity.

45

Name two devices that can interfere with the operation of a wireless network because they operate on similar frequencies.

Reference answer

Devices such as microwave ovens and cordless phones operating on 2.4GHz can interfere with wireless networks.

46

What is the reason for SDWAN based solutions being hot buy in today's enterprises?

Reference answer

SD-WAN solutions are popular because they offer cost-effective WAN connectivity by leveraging multiple link types (e.g., MPLS, broadband, LTE), provide centralized management, improve application performance through intelligent path selection, and enhance security with integrated features like encryption and firewalling.

47

What is the difference between Hub, Switch, and Router?

Reference answer

Here is a table explaining the difference between Hub, Switch, and Router – | Device | Layer (OSI Model) | Function | Example | | HUB | It works on Layer 1 i.e., Physical Layer | Connects multiple devices on a single network and broadcasts data to all ports. | A hub can be used to connect four computers in a small office network. | | Switch | It works on Layer 2 i.e., Data Link Layer | Connects multiple devices on one or more networks and forwards data to the destination port based on MAC address. | A switch can be used to create VLANs and reduce broadcast traffic. | | Router | It works on Layer 3 i.e., Network Layer | Connects two or more networks and routes data based on IP address. | A router can be used to connect a home network to the internet and provide firewall protection. |

48

At what layer IPsec works?

Reference answer

An IPsec works on layer 3 of the OSI model.

49

What is the OSI model and why is it useful?

Reference answer

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven distinct layers. Each layer has specific responsibilities, ensuring interoperability between different network devices and software. These layers are, from top to bottom: Application, Presentation, Session, Transport, Network, Data Link, and Physical. The OSI model is useful because it provides a common language for network professionals, simplifies network troubleshooting by breaking down complex communication processes into manageable parts, and promotes modularity in network design, allowing for easier updates and development of new technologies. It provides a structured way to understand how data travels from one application to another over a network.

50

What is capacity planning in Wi-Fi design?

Reference answer

Capacity planning goes a step beyond coverage and takes into account the different types and number of devices and applications that will connect to the network. Wireless network capacity is a measurement of the amount of traffic supported concurrently on a wireless network based on the bandwidth being consumed.

51

What is the difference between Layer 2 and Layer 3 roaming?

Reference answer

- Layer 2 roaming happens within the same subnet, where a client can move between APs without changing its IP address. Handoff is fast and usually seamless. - Layer 3 roaming occurs between different subnets. The client must obtain a new IP address via DHCP. This introduces slight delays, so network design often uses mobility anchors or controllers to minimize disruption.

52

How would you design a network to support a large number of IoT devices?

Reference answer

To support a large number of IoT devices, a multi-layered network design is essential. Key considerations include: leveraging protocols optimized for low bandwidth and intermittent connectivity like MQTT, CoAP, or LwM2M. Implementing a hierarchical network architecture with local gateways aggregating data before sending it to a central server reduces bandwidth consumption and processing load on the core network. Scalable infrastructure is critical. This includes using a cloud-based platform that can dynamically provision resources as the number of devices grows, utilizing message queues for asynchronous communication and buffering, and considering edge computing to process data closer to the source, reducing latency and bandwidth requirements. Strong security measures are also paramount, including device authentication, encryption, and regular security audits. Network segmentation helps isolate compromised devices.

53

How do you communicate complex network designs to non-technical stakeholders?

Reference answer

I use analogies and visuals extensively. When explaining network segmentation to executives, I compare it to a building's floor plan—different departments have their own spaces, and there are controlled entry points between them. When explaining redundancy, I talk about backup routes like an alternate commute route if your main highway is blocked. Visually, I use network diagrams, but I simplify them significantly for non-technical audiences—I show the big picture flow rather than every device and connection. I also connect everything back to business impact. Rather than saying ‘we're upgrading to 100GB core infrastructure,' I say ‘this upgrade will reduce application performance bottlenecks that currently cause 2-3 hours of lost productivity per month.' That business language resonates much better than the technical specs.

54

What is the difference between 802.11a, 11b, 11g, and 802.11n?

Reference answer

The difference between 11a, 11b, 11g, and 11n lies in terms of data rate, frequency of operation, distance coverage, and more.

55

What are the two types of wireless network setups?

Reference answer

Wireless networks can be established either as an Independent Basic Service Set (IBSS) which allows direct communication between devices without an access point, or a Basic Service Set (BSS) which uses a central access point to control access and connectivity for wireless devices on the network.

56

What is the difference between the ipconfig and ifconfig?

Reference answer

ipconfig stands for Internet Protocol Configuration, whereas ifconfig stands for Interface Configuration. The two have similar functions, except that the ipconfig command is used with the Windows operating system, while the ifconfig command is used on Linux and Mac computers. Both commands display network information. They display your IP address, network mask, and gateway information. However, `ifconfig` is not limited to displaying information. `ifconfig` allows you to modify network settings directly. You can enable or disable network interfaces. You can also assign new IP addresses through this command. `ipconfig` is more limited in what it can do. It mainly shows network details. Its main extra feature is refreshing your network connection. Many Linux users now prefer the newer `ip` command. It has replaced `ifconfig` in some newer distributions. But `ifconfig` is still commonly used and understood.

57

TCP handshakes, TCP Windowing

Reference answer

You can google it :)

58

Is it true that Wireless networking is only good for laptop computer?

Reference answer

- Although wireless networking offers obvious benefits to users of laptops who move from location to location throughout the day, there are benefits for users of fixed position computers as well: - So this is not such that wireless networking is only good for laptop computers but on preference basis it got more than fixed positions, as laptop computers are portable, flexible, ease to use and move. - Many schools and businesses have unsuitable building layouts or walls that cannot be wired for various reasons making it difficult or impossible to build a wired network. Wireless networking in these environments is a very cost effective alternative also providing future flexibility. - In cases where a small number of computers are separated from a main network a wireless link may be more cost effective than network cabling although the latter is perfectly feasible. - Temporary wireless LANs can easily be created for exhibitions, school or business projects, all without any trailing cabling.

59

Is there any way to recover my password for WLC?

Reference answer

Password Recovery: Use the CLI and Restore-Password command for versions 5.1 and later; otherwise, reset to factory defaults.

60

What device would you use for sharing a cable modem Internet connection with LAN users?

Reference answer

A router with NAT (Network Address Translation) capabilities is used to share a cable modem Internet connection with LAN users. The router translates private IP addresses from the LAN to the public IP address provided by the cable modem, enabling multiple users to access the Internet.

61

Walk me through how you would design a network for a company with 5,000 employees across 12 office locations, including a data center and cloud services.

Reference answer

First, I'd understand their current applications and criticality. For 5,000 employees across 12 locations, I'd recommend a hybrid hub-and-spoke topology with some mesh redundancy for critical sites. The core would likely be a pair of high-capacity switches at the data center with dual connections to our ISP and a backup carrier for redundancy. Each branch office would have dual connections back to the core—a primary and secondary link, potentially different carriers to avoid common failure points. For the data center network, I'd use a modern leaf-spine architecture with redundancy built in. This gives us the scalability to grow without redesigning the core. Cloud connectivity would be through a dedicated gateway or virtual firewall, segregating cloud traffic and applying security policies appropriately. For security, I'd implement network segmentation—critical systems in their own segments, guest wireless completely separate, applications in appropriate tiers. I'd use a distributed firewall or Cisco ACI to enforce policies consistently across locations. I'd also implement QoS to ensure voice and critical applications maintain performance even during congestion, and I'd build monitoring and analytics in from the start so operations teams have visibility. The key is designing this to scale from 5,000 to 10,000 employees without major changes, and ensuring that any single failure doesn't create a complete outage.

62

What is POC?

Reference answer

POC stands for Proof of Concept. It is a small-scale implementation or test to validate the feasibility, performance, and functionality of a proposed network solution before full deployment. It helps identify potential issues and ensures the solution meets requirements.

63

Can you explain your experience with BGP route optimization in a large-scale network?

Reference answer

I have optimized BGP in large-scale networks by implementing route filtering, traffic engineering with BGP attributes (AS-path, MED, local preference), and leveraging route reflectors to improve scalability. I use BGP peering with multiple ISPs for redundancy, optimize prefix aggregation to reduce overhead, and monitor route stability to ensure efficient, resilient, and high-performance network routing.

64

What is a subnet mask and why is it important?

Reference answer

A subnet mask is a number that defines how much of an IP address is allocated to the network, and how much is available for host devices. It's primarily used for dividing an IP address into a network and host address in a practice called subnetting. The importance of a subnet mask in networking is manifold. One of the main purposes is to improve the efficiency and speed of the network. By breaking a network into smaller subnetworks, locally transmitted data can stay within a particular subnet, reducing unwanted traffic on other subnets. This helps enhance network performance by limiting the chances of network collisions. Subnet masks also play a crucial role in IP routing, where they are used to determine whether the destination of a packet is within the same subnet or if it needs to be sent to a different subnet via a router. Moreover, subnetting increases the number of available IP addresses and improves network security by segregating different parts of a network. So, essentially, subnet masks are a key tool for organizing, managing, and securing your network resources efficiently.

65

What is Cognitive Radio, and what are its applications?

Reference answer

Cognitive radio is an intelligent wireless communication system that dynamically adapts its transmission or reception parameters based on the environment to avoid interference and optimize spectrum use. It is used in dynamic spectrum access and next-generation wireless networks.

66

How do the 2.4 GHz and 5 GHz frequency bands differ from each other?

Reference answer

| Feature | 2.4 GHz Band | 5 GHz Band | |---|---|---| | Coverage Range | Longer | Shorter | | Data Speed | Lower | Higher | | Interference | High | Low | | Channel Availability | Fewer non-overlapping channels | More non-overlapping channels | | Wall Penetration | Better | Weaker | | Best Use Case | Basic coverage, legacy devices | High-performance and high-density environments |

67

What bracket of network engineer salary are you looking for?

Reference answer

If youâre asked this question during your interview, be sure to give a respectful and realistic answer. To construct your answer, do some research into the salary brackets of a network engineer, taking into account the following: Your level of experience, What youâre currently earning, Your location, Whether the role is a contract or permanent position, If the role is onsite, remote or a combination of both, Other offers youâve recently had, What other companies are offering, The size of the organisation and what you could realistically expect them to offer you. To give you an idea of what to expect salary-wise from your potential future employer, hereâs what you could earn as a network engineer, according to Glassdoor. Entry-level network engineer salary: Â£34,000, Average network engineer salary UK: Â£45,000, Senior network engineer salary: Â£61,000. Hereâs how you could answer this type of network engineer interview question: âBased on my level of experience as a network engineer and research I have conducted around the position youâre offering, I would be grateful for you to offer me âXâ for this position.â Of course, the employer may have stated the network engineer salary they are offering or a bracket based on your experience. Donât be afraid to negotiate what the employer is offering, but like we say, be respectful if doing so.

68

What is the frequency range of the IEEE 802.11g standard?

Reference answer

2.4 GHz (specifically 2.4-2.4835 GHz).

69

How do you secure IoT devices on Wi-Fi?

Reference answer

To secure IoT devices on Wi-Fi: - Use WPA3 or other strong encryption methods - Isolate devices on a guest or dedicated VLAN - Monitor network traffic for anomalies or suspicious behavior - Regularly update firmware on IoT devices to patch vulnerabilities These practices help protect IoT devices and the enterprise network from security threats.

70

What is MPLS, and how does it improve network traffic flow?

Reference answer

MPLS, or Multiprotocol Label Switching, is a method for directing traffic on a network. It uses labels to forward data instead of long network addresses. This makes the process simpler and faster. Once data enters an MPLS network, it gets a label. Then the data is sent rapidly by network devices using this shorter label along an already established path. This eliminates the need for complicated routing choices at each step. Through this, a more efficient and reliable network is achieved, which can be helpful to businesses that require high-quality connections to run their applications. MPLS improves traffic flow in several ways: - It uses labels for faster forwarding decisions. - It creates predictable paths for data to follow. - It reduces the work routers have to do. - It allows for prioritizing important traffic. - It helps manage network congestion better.

71

What is the impact of client density on wireless network performance?

Reference answer

High client density can lead to network congestion and reduced performance due to increased competition for bandwidth and increased interference. Proper network design, including adequate access point placement and capacity planning, is essential to manage client density effectively.

72

What are the advantages of a network design based on the OSI model?

Reference answer

- Modularity: The OSI model allows for independent development and implementation of each layer, making it easier to upgrade or modify specific components. - Interoperability: The layered approach promotes interoperability between different network devices and systems. - Standardization: The OSI model provides a common framework for network communication, promoting consistency and understanding across the industry. - Flexibility: The modular design allows for adaptation to different network environments and technologies.

73

Describe in detail what happens when you open the web browser on a client to surf google.com

Reference answer

This article gives a very in-depth breakdown of the process. You just need to know the high level details mainly around DNS and HTTP request

74

What subnet mask would provide for a network with 50 hosts, while maximizing the number of available subnets?

Reference answer

255.255.255.192 (or /26). This provides 62 usable host addresses per subnet.

75

What strategies do you use to troubleshoot network issues effectively?

Reference answer

To troubleshoot network issues effectively, I start by using diagnostic tools to identify and isolate the problem. I then analyze data and logs to pinpoint the root cause, and implement and test solutions to confirm the issue is resolved.

76

What is network latency?

Reference answer

Network latency is the time delay between sending a data packet and receiving a response. It is measured in milliseconds (ms). High latency can affect network performance, especially for real-time applications like online gaming and video conferencing.

77

How do you troubleshoot roaming issues for VoIP clients?

Reference answer

To troubleshoot roaming issues for VoIP clients: - Ensure APs and the network support fast roaming (802.11r) - Verify that client devices are compatible with fast roaming protocols - Check signal overlap and channel planning for seamless handoffs - Monitor for call drops or packet loss during roaming events

78

What is a star topology and what are its characteristics?

Reference answer

The star topology is a type of network configuration where all devices, or 'nodes', are connected to a central device, such as a switch or a hub. Just imagine a star: the central device is in the middle, and the nodes branch out from its center like the points of a star. In a star topology, data transmissions from any node go through the central device, which then either forwards the data to the intended recipient node or broadcasts it to all nodes. This setup allows for easy fault detection and isolation since a malfunctioning node does not affect others. Additionally, adding or removing nodes is relatively easy and doesn't disturb the entire network's activity. Because the nodes are not directly interconnected, you only need to connect or disconnect them from the central device. The star topology is most commonly used in modern Ethernet LANs (Local Area Networks), including home, business, and school networks. It supports robustness (if one link fails, the rest of the network remains operational), simplifies management and troubleshooting, and is compatible with mass-market network devices like routers and switches. However, the central device's failure can bring down the whole network, and more cable length is required compared to other topologies, like a Bus topology.

79

What is IBSS, BSS, and ESS?

Reference answer

IBSS (Independent Basic Service Set) is a peer-to-peer network without an access point. BSS (Basic Service Set) is a group of stations sharing an access point. ESS (Extended Service Set) is a group of access points connected to the same WLAN, allowing roaming.

80

How would you put in place network security procedures?

Reference answer

Ensuring networks are protected and secured from the various threats out there in the ever-evolving tech landscape, now more than ever, businesses expect network engineers to have the skills to protect their organisation and that of their clients from potential attacks that could pose financial and reputational harm to a company. Therefore, itâs highly likely youâll be asked this type of network engineer interview question and hereâs how you can answer it. âThere are multiple effective approaches to achieve ensure your network is secure. First, I would ensure that all work computers and devices are installed with a reliable and up-to-date anti-virus programme. Secondly, Iâd recommend setting up and configuring appropriate firewalls to bolster network security. I would also consider implementing user authentication protocols to help enhance the protection of the network. By combining these measures, a highly secured network can be established.â If youâre entering a more entry-level network engineer job, you may only be expected to demonstrate your knowledge of network security. So at the very least, itâs worth having an understanding of this area of network engineering.

81

What types of challenges do you face most often when designing networks?

Reference answer

This technical question probes the candidate's experience with common network design challenges, such as coverage, capacity, interference, and scalability issues.

82

What is internetworking?

Reference answer

Internetworking is a combination of two words, inter and networking which implies an association between totally different nodes or segments. This connection area unit is established through intercessor devices akin to routers or gateways. The first term for the associate degree internetwork was interconnected. This interconnection is often among or between public, private, commercial, industrial, or governmental networks. Thus, associate degree internetwork could be an assortment of individual networks, connected by intermediate networking devices, that function as one giant network. Internetworking refers to the trade, products, and procedures that meet the challenge of making and administering Internet works.

83

What is CGMP(Cisco Group Management Protocol)?

Reference answer

CGMP is a simple protocol, the routers are the only devices that are producing CGMP messages. The switches only listen to these messages and act upon them. CGMP uses a well-known destination MAC address (0100.0cdd.dddd) for all its messages. When switches receive frames with this destination address, they flood it on all their interfaces Bluetooth so all switches in the network will receive CGMP messages. Within a CGMP message, the two most important items are: - Group Destination Address (GDA) - Unicast Source Address (USA) The group destination address is the multicast group MAC address, and a unicast source address is the MAC address of the host (receiver).

84

What is a network management system (NMS)?

Reference answer

An NMS is a software application that provides centralized control and management of network devices and resources. It allows for monitoring, configuration, troubleshooting, and reporting on network performance and security.

85

What are different network topologies?

Reference answer

Network topologies define how various devices are interconnected inside the network. Some of the common network topology types are: - Star Topology - Tree Topology - Bus Topology - Mesh Topology - Ring Topology - Point-to-Point Topology - Hybrid Topology

86

Which of the following wireless security protocols is considered the most secure and recommended for modern Wi-Fi networks? Options: WEP, WPA, WPA2, WPA3

Reference answer

WPA3

87

Explain some measures you have implemented to ensure the efficiency and productivity of wireless networks?

Reference answer

The answer to this question will help you understand the candidate's practical knowledge and ability to optimize wireless networks.

88

How do you ensure network scalability in your designs?

Reference answer

To ensure network scalability, I design with modular components and scalable technologies that can easily accommodate future growth. I also implement load balancing and redundancy strategies to handle increased traffic without compromising performance.

89

What cell edge and cell overlap would you survey for a voice deployment

Reference answer

-65 to -67 dBm

90

How would you go about designing an RF amplifier with a specific gain and bandwidth? Detail the design considerations.

Reference answer

Candidates are expected to articulate a clear design process for an RF amplifier, including considerations such as gain, bandwidth, stability, and linearity. Understanding of design trade-offs is key.

91

What are the differences between 802.11a, 802.11b, 802.11g, and 802.11n?

Reference answer

802.11a operates at 5GHz with up to 23 channels and data rate up to 54Mbit. 802.11b operates at 2.4GHz with 3 channels and data rate up to 11Mbit. 802.11g operates at 2.4GHz with 3 channels and data rate up to 54Mbit. 802.11n operates at 2.4GHz and 5GHz with channels depending on configuration and data rate up to 300-600Mbit.

92

What is DHCP and why is it useful?

Reference answer

DHCP (Dynamic Host Configuration Protocol) is a network protocol that automatically assigns IP addresses and other network configuration parameters (like subnet mask, default gateway, and DNS server addresses) to devices on a network. It is useful because it simplifies network administration. Without DHCP, each device would need to be manually configured with a unique IP address, which is time-consuming and prone to errors. DHCP reduces administrative overhead, prevents IP address conflicts, and allows devices to easily join and leave the network without manual intervention. Furthermore, it enables centralized management of IP address allocation.

93

Changes in WLAN-11ac compared to previous versions?

Reference answer

802.11ac Enhancements: Includes Multi-User MIMO, wider RF channels, and more spatial streams for faster and more efficient network performance. There are 2 variants of 802.11ac — phase 1 and phase 2.802.11ac is faster compared to previous standards because of the introduction of the below Multi-User MIMO (MU-MIMO) — Clients get on and off the network quicker, allowing more clients to be served, Pre Wave 2 an access point would talk to the clients one at a time and this was called SU-MIMO. Multi-user MIMO is important because it allows access points and their many antennas to transmit (or talk) to multiple client devices all at the same time. This helps maximize air-time efficiency so that each client, regardless of what version of 802.11 it is running, gets the amount of airtime it's supposed to get based on the technology supported. Wider RF Channels — Wave 2 improvement is the option to use 160-MHz channel widths. That's double what we saw with Wave 1 technology. Think of this as a 2 line interstate road where two additional lines have been added. The top speeds depend on the whether the AP supports 80-MHz or 160-MHz channels, as well as whether the wireless client devices tapping your network support Wave 2. Four Spatial Streams — Wave 2 also supports four transmitting and receiving antennas while the previous iteration supported only three receive antennas. Just like we see in the image below, With 4 spatial streams an AP could send 4 streams of data to the same client at the same time. The client can then aggregate this 4 streams and thus improve its throughput. It is also important to notice that on the AP side, the greater the number of receive antennas, the greater the distance that a particular data rate can be sustained.

94

At which layer of the OSI model does packet fragmentation occur to accommodate different network MTU (Maximum Transmission Unit) sizes?

Reference answer

Packet fragmentation occurs at the Network layer (Layer 3) of the OSI model to accommodate different network MTU sizes.

95

How do you stay current with network technology trends and advancements?

Reference answer

I stay current through multiple channels. I'm a member of Cisco Learning Network, and I maintain active CCNP and CCDP certifications, which requires staying on top of current technologies. I attend Cisco Live annually—it's great for both learning and connecting with other architects facing similar challenges. I also subscribe to industry publications like Network World and follow key voices on LinkedIn who work at major vendors and enterprises. More recently, I've started experimenting with emerging technologies in a home lab setup. For example, I've been testing SD-WAN solutions and 5G integration concepts so I understand them before my organization needs them. I also participate in our local IT professional association, which hosts monthly meetings where we discuss current challenges.

96

How do you troubleshoot high latency or packet loss in wireless networks?

Reference answer

To troubleshoot high latency or packet loss in wireless networks: - Check for RF interference or overlapping channels. - Verify AP placement and client distribution. - Monitor traffic using wireless monitoring tools. - Adjust QoS policies and perform client-side testing.

97

Can you describe a high-pressure situation in which your expertise in next-generation wireless technology was crucial for resolution?

Reference answer

This is a behavioral question aimed at understanding how the candidate applies their expertise during high-pressure situations. It gives insights on both their technical capabilities and problem-solving skills.

98

What technologies would you use to connect two remote offices, and what is inter-networking?

Reference answer

Technologies for connecting remote offices include VPN (Virtual Private Network): A VPN creates a secure, encrypted connection over the internet between remote offices. It allows remote sites to communicate as if they were on the same local network. Inter-networking refers to connecting multiple networks to allow them to function as a cohesive whole.

99

How does Wi-Fi work and what are the security protocols?

Reference answer

Wi-Fi allows devices to connect to a network wirelessly using radio waves. A wireless router broadcasts a Service Set Identifier (SSID), which is the network name, and devices within range can detect and connect to it. The router acts as a bridge, translating data between the wireless devices and the wired network or internet connection. Protocols like 802.11a/b/g/n/ac/ax define the standards for Wi-Fi communication, specifying data rates, frequencies, and other parameters. Security protocols are crucial for protecting wireless networks. WPA2 (Wi-Fi Protected Access 2) is a common protocol that uses AES encryption, while WPA3 is a more recent and secure standard. These protocols use a pre-shared key (PSK) or Enterprise authentication (like RADIUS) to grant network access. Older protocols like WEP are considered insecure and should not be used. MAC address filtering and disabling SSID broadcasting are additional (but less reliable) security measures.

100

The customer has procured a new 10 Mbps link which may increase up to 40 Mbps in next 5 years? What are considerations with link sizing?

Reference answer

Considerations include: 1) Selecting a router and interfaces that support future upgrades (e.g., modular interfaces for higher speeds). 2) Ensuring the service provider can scale the link (e.g., from 10 Mbps to 40 Mbps) without significant infrastructure changes. 3) Planning for oversubscription and QoS to handle growth. 4) Budgeting for potential hardware upgrades if the current equipment cannot support 40 Mbps.

101

Why is network documentation crucial?

Reference answer

Network documentation is crucial for several reasons. It serves as a central repository of information about the network's design, configuration, and operation, making troubleshooting and maintenance significantly easier. Accurate and up-to-date documentation allows network administrators to quickly identify problems, understand the impact of changes, and plan for future growth. Without proper documentation, tasks like onboarding new engineers, responding to outages, or implementing security measures become substantially more difficult and time-consuming. Comprehensive documentation reduces reliance on individual tribal knowledge, ensuring that the network can be managed effectively even in the absence of specific personnel. It also supports compliance efforts by providing an audit trail of network configurations and changes.

102

Explain the concept of airtime fairness in wireless networks.

Reference answer

Airtime fairness ensures that all devices connected to a wireless network receive an equal opportunity to transmit data. It prevents a single device from monopolizing network resources and improves overall network performance and user experience.

103

What network engineering skills do you possess?

Reference answer

As part of your network engineer interview preparation, itâs important you can communicate to the interviewer the various network engineering skills you possess, as this is likely to be asked during the interview. When answering this question, you could mention the more technical skills youâre equipped with, like your ability to troubleshoot hardware and software various types of network infrastructure issues as well as soft skills like organisational skills and your ability to manage projects on time. Hereâs one response you could give when answering these types of network engineer interview questions: âI have the technical, analytical, and problem-solving skills to troubleshoot network problems and resolve issues quickly and efficiently with little to no downtime for the end user.â

104

What experience do you have with designing wireless mesh networks?

Reference answer

This question assesses the candidate's experience with mesh network topologies, including routing protocols, self-healing capabilities, and deployment scenarios.

105

What is a network router?

Reference answer

A network router is a device that connects different networks and forwards data packets based on their IP addresses. It maintains a routing table that maps IP addresses to network paths, enabling efficient data routing between networks.

106

How can you share an internet connection across multiple devices?

Reference answer

An internet connection can be shared using a router with NAT (Network Address Translation) to allow multiple devices on a local network to access the internet through a single public IP address.

107

New Servers with Dual LAN ports are being setup in a Data Center. These are very critical servers since bulk of revenue-generating applications are stationed in these servers. What should be considerations while selecting the Access layer switch to support such a setup?

Reference answer

Considerations include: 1) High availability features (e.g., redundant power supplies, stacking) 2) Support for link aggregation (e.g., LACP) to utilize both server LAN ports for redundancy and increased throughput. 3) Low latency and high switching capacity. 4) Advanced QoS for traffic prioritization. 5) Support for 10G or higher uplinks to avoid bottlenecks.

108

How do you approach network scalability?

Reference answer

Network scalability is approached by designing modular and flexible network architectures, using scalable technologies like VLANs, SDN, and cloud services. For example, I design networks with modular switches that can be easily expanded and use cloud-based resources to scale computing power as needed.

109

What is the role of modulation in wireless communication?

Reference answer

Modulation is the process of varying a carrier signal's properties (amplitude, frequency, or phase) to encode information for transmission. It allows efficient use of bandwidth and helps signal propagation over long distances.

110

Which is the minimum parameter needed on the access point to allow a wireless client to operate on it?

Reference answer

SSID (Service Set Identifier) must be configured.

111

Design a solution for a company that needs to support both on-premises and multi-cloud infrastructure with consistent security and management.

Reference answer

This is complex because each cloud provider has their own networking model, and you need consistency across all of them. Connectivity: I'd implement SD-WAN or a similar overlay network. This abstracts the underlying connectivity—whether it's on-premises, AWS, Azure, or GCP. It gives you visibility and control across all connections. Security architecture: Define a consistent security model—maybe zero-trust, where every connection is authenticated and authorized regardless of where it originates. Use a cloud-native security platform that can operate across multiple clouds and on-premises. Implement consistent network segmentation policies—users and workloads should have the same access rules whether they're on-premises or in cloud. Management: Implement a multi-cloud management platform that gives you unified visibility and control. Some examples are tools from vendors like Cisco, VMware, or open source options. The goal is single pane of glass for networking across all environments. Specific implementation: Maybe on-premises infrastructure connects through SD-WAN to a central hub. Each cloud provider has a similar SD-WAN endpoint or native gateway. Traffic between locations flows through this overlay, giving you visibility and control. Security policies are defined once and enforced consistently everywhere. Cost optimization: By not locking into any single cloud provider, you maintain flexibility. You can move workloads or use different clouds for different purposes based on cost and capability, not because you're locked in. This architecture is complex, but organizations increasingly need it. The payoff is flexibility, security consistency, and the ability to optimize costs.

112

What is a Virtual Private Network (VPN) and how does it enhance security?

Reference answer

A Virtual Private Network (VPN) creates a secure and encrypted connection over a public network, such as the Internet. It enhances security by masking the user's IP address, encrypting data traffic, and allowing secure remote access to a private network.

113

How do you monitor real-time client performance?

Reference answer

To monitor real-time client performance, use WLC dashboards or tools like Cisco DNA Center to track key metrics such as: - Signal-to-noise ratio (SNR) - RSSI levels - Packet loss - Latency and throughput This allows proactive detection of performance issues and helps optimize the wireless network for reliable client connectivity.

114

Suppose some users can access the Internet but cannot access the company server. What should you troubleshoot first?

Reference answer

First, check whether the server is reachable on the local network. You can use commands like "ping" or "traceroute" to check this. If the user can access the Internet but not the internal server, the issue must be related to: - Incorrect VLAN configuration - Firewall rules are blocking access - DNS resolution issue - Server down or disconnected - Incorrect gateway settings You should also verify: - IP configuration of the client - Server status - Switch port VLAN assignment - ACLs or firewall policies

115

What are some common network security threats?

Reference answer

Some common network security threats include malware (viruses, worms, trojans), phishing attacks (deceptive emails or websites), ransomware (encrypting data and demanding payment), denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks (overwhelming a system with traffic), man-in-the-middle (MitM) attacks (intercepting communication), and SQL injection (exploiting vulnerabilities in databases). It's also important to be aware of insider threats (malicious or negligent employees), weak passwords, unpatched software vulnerabilities, and social engineering (manipulating individuals to gain access or information). Staying informed about the latest threat landscape and implementing appropriate security measures are crucial for protecting a network.

116

What is the maximum data rate for the 802.11a standard?

Reference answer

Up to 54 Mbit.

117

What is BGP, and how does it function in network routing?

Reference answer

BGP (Border Gateway Protocol) is an inter-domain routing protocol used to exchange routing information between different autonomous systems (ASes) on the internet. It helps manage how data is routed across the internet. Example of How BGP Is Involved- Example with ‘traceroute app.lightrun.com' - From Your Network (ISP): Your ISP's network (which is part of an AS) sends packets to a neighboring AS, which might be a larger backbone provider like Cogent. - Cogent Communications: Cogent receives the packets and uses BGP to determine the best route to the destination network. - AWS Network: Finally, the packets reach AWS's network. AWS's own internal routing, potentially influenced by BGP routes from different providers, directs the packets to the specific AWS service (like app.lightrun.com).

118

Explain the difference between co-location interference studies and cumulative exposure assessments in the context of RF engineering and compliance.

Reference answer

The candidate is expected to demonstrate their understanding of RF engineering concepts related to exposure and interference, and how these studies are vital for compliance with regulatory limits.

119

Which of the following statements best describes the primary function of the Address Resolution Protocol (ARP)? options: To resolve domain names to IP addresses, To resolve IP addresses to MAC addresses, To resolve MAC addresses to IP addresses, To resolve port numbers to application names

Reference answer

To resolve IP addresses to MAC addresses.

120

What is ICMP and what is its role in networking?

Reference answer

ICMP, or Internet Control Message Protocol, is a supporting protocol that sends feedback to a source host regarding any network-related issues in processing its packet transmissions. While ICMP does not transmit application data between network hosts like TCP or UDP does, it plays an essential role in managing and controlling network operations. ICMP messages are usually generated in response to errors in IP datagrams (packets), or for diagnostic or routing purposes. Common ICMP messages include "Destination Unreachable" messages, "Time Exceeded" messages (used in tools like Traceroute to detect routing loops or excessive transit delays), "Redirect" messages (used to update routing information) and "Echo Request/Reply" messages (used in tools like Ping to check network connectivity). Overall, ICMP helps maintain network health by reporting problems back to the devices responsible for transmitting data. Without it, these devices couldn't tell whether data is taking too long to arrive, is being delivered inaccurately, or if there are any other network-related issues happening. This makes ICMP an integral part of IP operations.

121

What factors should be considered when designing firewall policies?

Reference answer

Firewall policies are critical for securing a network while ensuring essential services function smoothly. A well-structured firewall policy should consider the following: - Least Privilege Principle: Allow only the necessary traffic for business operations. - Stateful Inspection: Monitor active connections to permit or block traffic dynamically. - Application Awareness: Implement rules based on specific applications, not just ports. - Regular Updates: Keep policies updated to address emerging threats and vulnerabilities.

122

How do you handle interference in a wireless network?

Reference answer

To handle interference: - - Identify the source of interference using spectrum analyzers. - Change wireless channels to reduce overlap with other networks. - Adjust access point placement and transmit power. - Implement shielding or use different frequency bands to mitigate interference.

123

What are the key parameters you monitor when conducting preventive maintenance on RF systems, and why?

Reference answer

Candidates are expected to identify critical RF system parameters like power levels, signal-to-noise ratio, and others that need regular monitoring to prevent failures, revealing their preventive mindset and understanding of RF system operation.

124

How do you configure and troubleshoot a mesh network?

Reference answer

A22: To configure and troubleshoot a mesh network: - Set up root and non-root APs with properly planned channels - Ensure strong connectivity between mesh nodes - Monitor throughput and latency between nodes to identify performance issues - Adjust AP power levels and placement to eliminate coverage gaps or dead zones This approach helps maintain reliable performance and seamless connectivity in mesh deployments.

125

What tools and techniques do you use for network troubleshooting?

Reference answer

Common network troubleshooting tools include ping, traceroute (or tracert on Windows), nslookup (or dig on Linux/macOS), ifconfig (or ipconfig on Windows), and tcpdump (or Wireshark for a GUI). These tools help determine network reachability, route tracing, DNS resolution, IP configuration, and packet capture for detailed analysis. Techniques involve a systematic approach like the OSI model, starting from the physical layer (checking cables and connectivity) up to the application layer. Other techniques include checking IP configuration, DNS settings, routing tables, and firewall rules. Isolating the problem by testing connectivity between different points in the network and analyzing error messages are also helpful.

126

Explain the difference between 2.4 GHz and 5 GHz frequency bands.

Reference answer

The 2.4 GHz band offers longer range but is more susceptible to interference and congestion from other devices (e.g., microwaves, Bluetooth). The 5 GHz band provides faster speeds and less interference but has a shorter range and lower penetration through obstacles.

127

What is a default gateway and why is it important?

Reference answer

A default gateway is an essential component of networking that acts as a bridge connecting your local network to the internet. When a device wants to communicate with a system outside its local network, it doesn't always know the pathway to that external network, that's where a default gateway comes in. Consider the gateway as a translator between a small local network and the vast internet. When a device sends a request to access a resource outside its local network, that request is sent to the default gateway. The gateway, usually your router, then takes it from there to send the request to the internet. In other words, the default gateway is the device that routes traffic from the local network to other networks or subnets. Without it, your local network would be an island isolated from the rest of the digital world.

128

A host, configured to receive its IP address automatically, needs to keep its IP address. What message is sent by the host to the DHCP server to accomplish this?

Reference answer

The host sends a DHCPREQUEST message to the DHCP server to request to keep its IP address.

129

How do you troubleshoot weak mesh network performance?

Reference answer

To troubleshoot weak mesh network performance: - Ensure all mesh nodes are within proper RF range for stable connectivity - Check for interference from nearby networks or electronic devices - Adjust AP power levels to optimize signal strength - Monitor latency and throughput between mesh nodes to identify bottlenecks These steps help maintain reliable performance and connectivity in enterprise mesh deployments.

130

What is QoS (Quality of Service) in a network?

Reference answer

QoS involves managing network traffic to ensure performance for high-priority applications. Techniques include: - Traffic Shaping: Controls the rate of outbound traffic to smooth out bursts and maintain a steady flow. - Queuing: Manages packets in different queues based on priority or traffic type, ensuring orderly processing. - Prioritization: Assigns different priority levels to various types of traffic, ensuring that higher-priority traffic is processed first.

131

What is the role of ARP?

Reference answer

ARP translates a known IP address into a physical MAC address. Devices on a local network need a MAC address to communicate directly. ARP is the protocol used to discover it. When a device needs to send data, it knows the destination IP address. It uses an ARP request to ask the network for the matching MAC address. The device with that IP address sends an ARP reply. This reply contains its MAC address. The requesting device can now send its data. ARP is an essential process for discovering addresses on a local network.

132

What is a firewall and how does it work?

Reference answer

Firewalls are a kind of network security technique used to restrict unauthorized access to the network. A device or program that is capable of filtering both incoming and outgoing data within a private network, applying a predefined set of regulations to identify and prevent cyber threats. They serve as an essential element of network security. The majority of operating systems are equipped with a rudimentary integrated firewall. However, the utilization of a firewall application from a third-party source offers enhanced protection measures. Working: Firewalls are used to monitor and control the flow of network traffic. It evaluates and determines what traffic to allow or restrict on a specific set of regulations. The firewall can be understood as a guard placed at the entry of a computer system, carefully allowing entry only to authorized sources or IP addresses within the network. The regulations are derived from various factors as specified by the packet data, such as their origin, destination, and other relevant attributes. In order to prevent cyberattacks, traffic originating from suspicious sources is blocked.

133

How do you keep up-to-date with changes in regulatory compliance standards relevant to RF engineering?

Reference answer

Looking for candidates to detail their strategies for staying informed on regulatory updates, such as subscribing to relevant newsletters, attending seminars, or participating in industry groups. This reflects their commitment to ongoing compliance.

134

What is a VLAN and why is it used?

Reference answer

A VLAN (Virtual Local Area Network) is a logical grouping of network devices that allows them to communicate as if they were on the same physical network segment, regardless of their actual physical location. It enables network administrators to segment a network into broadcast domains. VLANs are used for several reasons. Primarily, they enhance security by isolating sensitive data and traffic. Secondly, they improve network performance by reducing broadcast traffic within each VLAN. Finally, they simplify network management by allowing administrators to group users and devices based on function or department rather than physical location, making moves, adds, and changes easier.

135

What knowledge do you have of network protocols?

Reference answer

Industry-standard protocols such as WANs, wireless LANs, VPNs, and TCP/IP are part of the fundamental expertise a network engineer should be equipped with. An interviewer will ask these types of network engineer interview questions to understand your level of technical knowledge within this core area. To know how to prepare for network engineer interview questions like this one, check out our example response: âWith extensive experience in working with TCP/IP, I have honed my skills in resolving technical issues remotely by accessing the IP addresses of the user. I also possess expertise in installing and configuring wireless LAN technology, enabling seamless internet or intranet access within office spaces or designated areas. Moreover, my proficiency extends to deploying secure VPNs for multiple businesses, ensuring their data remains safeguarded and accessible only to people with the necessary authority. I recognise how these networking protocols represent fundamental components of standard technology crucial to a network's day-to-day functionality.â

136

Which of the following CIDR notations represents a network with a subnet mask of 255.255.255.0?

Reference answer

/24

137

What is the difference between a switch and a router?

Reference answer

A switch connects devices within the same network, using MAC addresses to send data to the correct device. It improves network performance by reducing unnecessary traffic. A router connects different networks and directs data between them using IP addresses. Routers are necessary for internet access, as they determine the best path for data to travel.

138

Describe a time you had to troubleshoot a critical network outage under pressure.

Reference answer

In my previous role, we experienced a sudden outage affecting a critical e-commerce application during peak shopping hours. The initial reports pointed to a network connectivity problem, but the scope and root cause were unclear. Under immense pressure to restore service quickly, I began by isolating the affected components. Using network monitoring tools and ping commands, I traced the issue to a misconfigured firewall rule that was inadvertently blocking traffic to the application servers. The firewall rules had been updated recently for a penetration test. After identifying the faulty rule, I immediately adjusted the firewall configuration following our change management process. I documented the changes and communicated the resolution to the stakeholders. I also collaborated with the security team to ensure the restored rule didn't introduce vulnerabilities. Finally, we conducted a post-incident review to prevent similar issues by improving our configuration change management and penetration testing rollback processes.

139

What is a node?

Reference answer

Types of technical network engineer interview questions like this can be answered in this simple but effective way that tells the interviewer you know what youâre talking about. âA node is a point or junction where connections occur, representing a computer or device within a network. To establish a network connection, at least two nodes are required to interact with each other.â

140

What is the difference between HTTP and HTTPS?

Reference answer

HTTP (HyperText Transfer Protocol) is a protocol used for transmitting data over the web. HTTPS (HTTP Secure) is an extension of HTTP that uses encryption (SSL/TLS) to secure data transmission between a web server and a browser. HTTPS ensures that data is encrypted and secure from eavesdropping and tampering.

141

Why is WPA encryption preferred over WEP?

Reference answer

WPA is preferred over WEP because WEP is insecure and can be hacked in 5-10 minutes, while WPA uses TKIP for dynamic key changes and improved security.

142

Which encryption type does WPA2 use?

Reference answer

WPA2 uses AES: A newer Wi-Fi encryption solution that is more secure than the older TKIP used in WPA.

143

A new branch office has terminated a new Internet Link but there is no firewall in the setup to protect the network. What should the best possible solution to provide network security?

Reference answer

The best possible solution is to deploy a firewall at the network edge between the Internet link and the LAN. If budget is a concern, consider a Unified Threat Management (UTM) appliance or a router with integrated firewall features (e.g., Cisco ASA or Fortinet FortiGate) to provide basic security.

144

What is SNMP and how is it used in network management?

Reference answer

SNMP, or Simple Network Management Protocol, is a protocol used in networking for managing and monitoring network devices. Think of it as a communication rulebook for network devices like routers, switches, servers, printers, and even laptops and desktops. SNMP allows network administrators to oversee network performance, find and solve network issues, and occasionally, plan for network growth. It operates by sending protocol data units (PDUs) to different parts of a network, and upon arrival, the PDU is used for monitoring and controlling these network devices. The protocol includes a set of standards for network management, including an application layer protocol, database schema, and a set of data objects. To put it simply, SNMP provides a way to get or set the values of variables in the database schema, which is particularly useful for tracking and controlling network behavior.

145

Describe the concept of Wi-Fi security and list some common security protocols.

Reference answer

Wi-Fi security protects wireless networks from unauthorized access and data breaches. Common security protocols include: - - WEP (Wired Equivalent Privacy): An older and less secure protocol. - WPA (Wi-Fi Protected Access): Provides improved security over WEP. - WPA2: Uses AES encryption for stronger security. - WPA3: Offers enhanced security features and protection against brute-force attacks.

146

What is Confidentiality, Integrity & Availability?

Reference answer

The CIA triad can be broadly defined as: Confidentiality – means information is not disclosed to unauthorized individuals, entities, or processes. For example, if we say I have a password for my Gmail account but someone saw it while I was doing login into my Gmail account. In that case, my password has been compromised and Confidentiality has been breached. Integrity – means maintaining the accuracy and completeness of data. This means data cannot be edited in an unauthorized way. For example, if an employee leaves an organization then in that case data for that employee in all departments like accounts, should be updated to reflect the status to JOB LEFT so that data is complete and accurate in addition, this is only authorized persons should be allowed to edit employee data. Availability – means information must be available when needed. For example, if one needs to access information about a particular employee to check whether an employee has outstood the number of leaves, that case, it requires collaboration from different organizational teams like network operations, development operations, incident response, and policy/change management. Denial of service attack is one of the factors that can hamper the availability of information.

147

What is the function of a wireless network management system (WMS)?

Reference answer

A wireless network management system (WMS) provides centralized control and monitoring of wireless network components. It helps manage configuration, performance, security, and troubleshooting, offering insights and analytics to optimize network operations.

148

What is the purpose of using multiple SSIDs on an access point?

Reference answer

Multiple SSIDs allow an access point to broadcast different network names, enabling the segregation of traffic for various user groups (e.g., employees, guests). It helps in managing network access and applying different security policies for each SSID.

149

What is a network management console?

Reference answer

A network management console is a centralized interface that provides access to network management tools and resources. It allows administrators to monitor, configure, troubleshoot, and report on network performance and security.

150

A user can ping an IP address, but cannot open any website using its Domain name. What might be the issue?

Reference answer

This usually happens because of a DNS issue. In this scenario, network connectivity is working because IP communication succeeds, but name resolution is failing. You should check the configured DNS Server, using: "nslookup google.com" - Verify internet DNS reachability - If the issue doesn't get resolved, you can change the DNS to public DNS for some time, using 8.8.8.8 and 1.1.1.1

151

How do you ensure that an RF circuit remains stable and does not oscillate?

Reference answer

Interviewers should listen for practical solutions to RF circuit instability. The candidate should mention common issues, like oscillations or signal drift, and how they maintain stability, such as ensuring correct component values, biasing, or using feedback loops. They should also share specific examples of when they've encountered and resolved stability issues.

152

What is the difference between a switch and a hub?

Reference answer

A switch and a hub are both networking devices that connect multiple devices together on a network, but they operate differently. A hub is a basic network device that connects multiple devices together on a Local Area Network (LAN) and sends incoming data packets to all connected devices, regardless of the intended recipient. This can lead to lots of unnecessary network traffic, plus it's not exactly secure, since all the data is sent to all devices. A switch, on the other hand, is a bit smarter. It can examine and understand the data it receives, and it can direct data to a specific device on the network instead of all of them. It does this by maintaining a list of all the devices connected to it and the corresponding physical (MAC) addresses. This contributes to a much more efficient and secure network because the data only goes where it needs to. So, in essence, while both switches and hubs are used for connecting devices in a network, switches offer better performance and security due to their ability to direct traffic rather than just broadcasting it to all connected devices.

153

What are the two methods of using a key for WPA and WPA2?

Reference answer

Preshared key (used at home, easy but lacks control) and 802.1x with EAP (used for serious setups, authenticates users and is more secure).

154

What is an RF site survey, and why is it important?

Reference answer

An RF site survey identifies signal strength, interference sources, and optimal AP placement. It ensures reliable coverage and capacity planning in enterprise environments. Tools like Ekahau and AirMagnet are commonly used.

155

What is Quality of Service (QoS) and how can it be implemented?

Reference answer

Quality of Service (QoS) refers to the ability of a network to provide differentiated service to specific network traffic. The goal of QoS is to improve the user experience by prioritizing critical traffic and minimizing latency, jitter, and packet loss for delay-sensitive applications like VoIP and video conferencing. QoS can be implemented through various mechanisms to prioritize network traffic. Some common techniques include: traffic classification and marking, queuing (e.g., Priority Queuing, Weighted Fair Queuing), traffic shaping, and congestion avoidance.

156

What is the difference between Wi-Fi 5 (802.11ac) and Wi-Fi 6 (802.11ax)?

Reference answer

Wi-Fi 5 (802.11ac): Operates on the 5 GHz band and offers high-speed wireless connectivity with wider channels and MIMO. Wi-Fi 6 (802.11ax): Enhances Wi-Fi 5 by providing faster speeds, lower latency, and better performance in dense environments through technologies like OFDMA and MU-MIMO.

157

What are the key considerations while selecting a Switch in a solution?

Reference answer

Key considerations include: 1) Port density and speed (e.g., 1G, 10G, 40G) 2) Switching capacity and forwarding rate 3) Layer 2 vs. Layer 3 capabilities 4) Power over Ethernet (PoE) requirements 5) Redundancy (e.g., redundant power supplies, stacking) 6) Management features (e.g., SNMP, CLI) 7) Budget and total cost of ownership.

158

Explain the concept of network security.

Reference answer

Network security refers to the measures taken to protect a network from unauthorized access, use, disclosure, disruption, modification, or destruction. It involves implementing security protocols, firewalls, intrusion detection systems, and access control measures to safeguard data and network resources.

159

How do you secure enterprise wireless networks against threats?

Reference answer

I ensure enterprise wireless networks remain secure by implementing strict authentication, encryption, and continuous monitoring. Wireless networks are highly vulnerable to attacks like unauthorized access, data interception, and rogue APs, so proactive security measures are essential. Here are the key steps I take to secure them: - Strong Encryption: I enforce WPA3 encryption to protect data and prevent unauthorized interception. - Access Control: I use 802.1X authentication with RADIUS to ensure that only approved users and devices can connect. - Network Segmentation: I separate guest, employee, and critical network traffic to limit access and reduce risk. - Regular Audits: I conduct frequent security assessments to identify rogue access points and misconfigurations. - Intrusion Detection: I deploy monitoring tools to detect, alert, and respond to suspicious activities in real time. - Firmware Updates: I ensure all wireless devices have up-to-date firmware to patch security vulnerabilities.

160

What challenges arise when transitioning from IPv4 to IPv6, and how can they be managed?

Reference answer

Transitioning from IPv4 to IPv6 presents challenges, but careful planning ensures a smooth process. Compatibility is a major issue, as older devices may not support IPv6. To manage the transition from IPv4 to IPv6, I use a dual-stack approach to ensure compatibility with older devices. For migration, I implement tunneling and NAT64 to maintain communication. I also update firewall policies, enable IPv6 security features, and conduct regular security audits. To ensure a smooth transition, I train IT teams, update documentation, and integrate IPv6 gradually into the network.

161

How does WPA3 differ from WPA2?

Reference answer

WPA3 provides enhanced security compared to WPA2 by offering individualized encryption for open networks, stronger password-based authentication, and protection against offline dictionary attacks. These improvements make both enterprise and public Wi-Fi networks more secure and significantly reduce the risk of unauthorized access.

162

What are the main components of an Enterprise Wireless Network?

Reference answer

The main components of an enterprise wireless network typically consists of: - Access Points (APs): Provide wireless connectivity to clients - Wireless LAN Controllers (WLCs): Centralized management, security, and policy enforcement - Authentication Servers (RADIUS/ISE): User authentication and authorization - Switching Infrastructure: Provides power (PoE) and network connectivity - Management Tools: For monitoring, analytics, and troubleshooting

163

What is Spanning Tree Protocol, and how does it work?

Reference answer

Spanning Tree Protocol (STP) is a protocol used in switches to prevent network loops. A network loop happens when there are multiple paths between switches, and data keeps moving in circles inside the network. STP helps prevent these loops by blocking extra paths and keeping only one active path. STP works in a few simple steps: Step 1: STP chooses one switch as the main switch, called the Root Bridge. Step 2: Every switch finds the shortest path to the root bridge. Step 3: If there are multiple paths, STP blocks the unnecessary ports. This removes the loops from the network.

164

How do you design a scalable network?

Reference answer

Designing a scalable network requires planning for future growth and flexibility. Expect candidates to outline a similar process: Implement a modular architecture, using hierarchical models like core, distribution, and access layers; Use scalable technologies like VLANs and IP subnets to segment traffic; Implement redundant links and devices to handle increased traffic loads; Choose equipment that supports higher capacity and can be upgraded easily; Plan for efficient routing and switching to minimize bottlenecks, and ensure the network can accommodate new users, devices, and applications.

165

What is the role of a Mobility Controller in a Cisco Wireless Network?

Reference answer

A Mobility Controller (WLC) manages multiple access points, enforces security policies, configures SSIDs, and handles client authentication. It also manages seamless roaming, provides centralized logging and monitoring, and enforces Quality of Service (QoS) for voice and video applications. Additionally, WLCs support redundancy to ensure network reliability in case of AP or controller failures.

166

Can you provide an example of a time you led a team to design a scalable and efficient network architecture?

Reference answer

At Telstra, I led a team to design a new multi-site network architecture to support a significant increase in data traffic. We assessed existing infrastructure and identified bottlenecks. By implementing a SD-WAN solution, we improved bandwidth efficiency by 40% and reduced latency by 30%. This project not only enhanced user experience but also saved the company approximately 20% in operational costs.

167

Which layer of the OSI model is responsible for segmenting data into smaller packets for transmission?

Reference answer

The Transport layer (Layer 4).

168

What are Nodes and Links?

Reference answer

Two or more computers form a network when some wire or fiber optics physically links them. In this configuration, the computers are referred to as nodes, and the link is the actual medium of communication, i.e., the physical medium.

169

What are some common network management tools?

Reference answer

Common network management tools include: - SolarWinds Network Performance Monitor (NPM): For network performance monitoring and troubleshooting. - Wireshark: For packet analysis and network traffic monitoring. - Nagios: For network monitoring and alerting. - ManageEngine OpManager: For comprehensive network management, including performance monitoring and fault management.

170

What considerations do you take into account when implementing Zero Trust Network Architecture (ZTNA)?

Reference answer

Zero Trust is a security model that assumes no implicit trust within the network. When implementing ZTNA, I focus on: - Least Privilege Access: Ensuring users/devices have access only to necessary resources. - Micro-Segmentation: Restricting lateral movement by segmenting the network into secure zones. - Continuous Authentication: Using multi-factor authentication (MFA) and identity verification mechanisms. - Network Visibility: Deploying real-time monitoring and anomaly detection tools. - Policy Enforcement: Using software-defined policies to control access dynamically. With these measures, I create a highly secure and resilient network environment.

171

How do you handle interference in an RF system?

Reference answer

Interviewers should check if the candidate can recognize different types of interference, such as signal overlap or unwanted noise from nearby devices. Look for practical methods the candidate has used, like adjusting frequency bands, power levels, or implementing filtering solutions. A real-world example where the candidate resolved interference effectively would show their hands-on experience.

172

What are your weaknesses, and how are you addressing them?

Reference answer

This question evaluates the candidate's self-awareness and commitment to professional growth, including their strategies for improving areas of weakness.

173

How do you ensure network security is built into your architecture from the beginning?

Reference answer

Security is integrated into every layer of the architecture I design. I follow a ‘defense in depth' model, which means no single point of failure in your security posture. At the perimeter, I deploy next-generation firewalls with threat intelligence. Inside the network, I implement segmentation so that if one area is compromised, the attacker can't automatically move to other critical systems. I also ensure proper access controls using least privilege principles and encrypt all management traffic. Beyond the technical controls, I work with the security team early to understand compliance requirements—whether that's PCI-DSS, HIPAA, or others—and design the network to meet those standards from day one rather than retrofitting controls later. I also maintain certifications like Security+ to stay current on emerging threats.

174

What is a network gateway?

Reference answer

A network gateway is a device that connects two networks with different protocols or addressing schemes. It acts as a bridge between networks and translates data between them. For example, a gateway might connect an Ethernet network to a wireless network or translate between IPv4 and IPv6 addresses.

175

What is a trunk port?

Reference answer

A trunk port is a network link that carries data for many VLANs over a single connection. Its main job is to connect switches, allowing VLANs to stretch across multiple devices. Trunk ports handle traffic from many different VLANs. Trunk ports add a special tag to each piece of data. This tag identifies which VLAN the data belongs to. The receiving switch reads the tag to send the data to the correct destination. This system makes the network more efficient and flexible.

176

Which of the following factors is primarily used by Spanning Tree Protocol (STP) to elect the root bridge in a network?

Reference answer

The bridge priority and MAC address are used to elect the root bridge. The switch with the lowest bridge priority becomes the root bridge.

177

What is network virtualization and what are its benefits?

Reference answer

Network virtualization abstracts network resources (hardware and software) into logical components, enabling flexible and dynamic network management. It decouples network functions from the underlying physical infrastructure. This allows for creating multiple virtual networks on a shared physical infrastructure. Benefits include improved network agility through rapid provisioning and deployment of network resources. It significantly enhances efficiency by optimizing resource utilization, reducing capital expenditures (CAPEX) and operational expenses (OPEX). It also allows for better scalability and simplified network management. Virtualization facilitates faster innovation and service delivery.

178

What is a network security appliance?

Reference answer

A network security appliance is a specialized hardware device that provides security functions for a network. These appliances can include firewalls, intrusion detection systems, VPN gateways, and other security tools, protecting the network from various threats.

179

What is load balancing in networking and how does it work?

Reference answer

Load balancing in networking is the process of distributing network traffic across multiple servers or paths to ensure no single server or path gets overwhelmed. This can optimize responsiveness and increase the availability of applications. At its core, a load balancer sits between client devices and the backend servers. When a client makes a request, the load balancer uses an algorithm to determine which server is best suited to handle the request, based on factors like server availability, current load, and response times. Then, it forwards the client's request to that selected server. There are various load balancing algorithms, and the choice of which to use depends on the specific needs of the network. For example, a round robin algorithm cycles through all servers in order, while a least connections algorithm gives the request to the server with the fewest active connections. Apart from ensuring efficient use of resources and preventing server overload, load balancers can also provide failover capabilities. If a server goes down, the load balancer can automatically redirect its traffic to the remaining operational servers, enhancing network reliability and availability.

180

How do you implement QoS on wireless networks?

Reference answer

To implement QoS on wireless networks: - Configure QoS policies on WLC or APs to prioritize voice/video. - Use Wi-Fi Multimedia (WMM) for client devices. - Map DSCP values to corresponding QoS levels. - Monitor performance using tools like Cisco DNA Center or Wireshark.

181

How would you design a Wi-Fi network for a multi-floor corporate building?

Reference answer

To design a Wi-Fi network for a multi-floor corporate building, conduct a detailed RF site survey for each floor and place APs strategically to ensure coverage with minimal interference. Use 5 GHz for high-density areas like conference rooms and 2.4 GHz for general coverage. Configure the WLC for centralized management and seamless roaming, and plan redundancy for critical areas to maintain reliability and prevent downtime.

182

What is background scan?

Reference answer

♣ When STA is connected to AP and STA wants to scan, the STA sends null frame with PM=1 to AP. Then STA does Active/Passive scan on other channel. Then STA comes back to original channel [Connected AP channel] and sends null frame with PM=0 to AP. Example: This type of scan observed at the time of Roaming.

183

What is the difference between Wi-Fi and Ethernet?

Reference answer

Imagine your phone connecting to the internet. Wi-Fi is like using the phone's speaker to talk to someone – it's wireless. Ethernet is like using a wired headset. So, Wi-Fi is a wireless way to connect devices to the internet using radio waves. Ethernet is a wired connection, where you plug a cable directly from your device (like a computer) into your internet router or modem. Ethernet is generally faster and more reliable than Wi-Fi, but Wi-Fi is more convenient since you don't need cables.

184

What is the primary benefit of using VLANs (Virtual LANs) in a network?

Reference answer

To logically segment a network into separate broadcast domains, improving security, performance, and manageability.

185

What are the data rates of 802.11b, 802.11g, 802.11a, 11n and 11ac (they can also ask history of 802.11b, g and a). There are too many 802.11n MCS rates so most likely you should not expect a question like that.

Reference answer

802.11n rates: http://mcsindex.com/ 802.11ac MCS rates

186

What are the different modes of a Cisco Access Point (AP) operation?

Reference answer

Modes Include: Local, REAP, Monitor, Rogue Detector, Sniffer.

187

What are the protection mechanisms to secure server farms?

Reference answer

Protection mechanisms include: 1) Firewalls (network and host-based) 2) Intrusion Detection/Prevention Systems (IDS/IPS) 3) Access control lists (ACLs) on switches and routers 4) Load balancers with DDoS protection 5) Regular patching and vulnerability scanning 6) Network segmentation (e.g., VLANs) to isolate server traffic.

188

What are some key measures for securing a network?

Reference answer

Securing a network involves numerous strategies and techniques, but here are a few key measures: Set up Firewalls: Firewalls act as the first line of defense against external threats by monitoring incoming and outgoing traffic and blocking suspicious activities based on predefined rules. Use Strong, Unique Passwords: Employ a strong password policy that includes changing passwords regularly, avoiding common or easily guessable passwords, and using a mix of letters, numbers, and symbols. Encrypt Data: Encryption converts data into code that can only be read if the user has the correct decryption key. Use secure protocols like HTTPS, and consider using a VPN for all online connections. Regular Updates: Ensure all systems and software are up to date as outdated software often contains vulnerabilities that can be exploited by attackers. Network Segmentation: Divide the network into various segments to isolate different types of traffic from each other. This can limit the spread of potential threats and protect sensitive information. Install Antivirus/Malware Software: This can help to scan, identify, and remove any malicious software present in the devices connected to your network. Remember, security is not a one-off task but a continuous process. Regular audits and monitoring are crucial to ensure the effectiveness of the implemented security measures, with adjustments made as necessary to adapt to evolving threats.

189

What are some common network monitoring tools and their key features?

Reference answer

Expect candidates to mention software like SolarWinds, PRTG, and Nagios. Some key features they might talk about are: Network monitoring; Performance analysis; Traffic flow analysis; Alerting systems.

190

What is a MAC address?

Reference answer

The Media Access Control (MAC) address holds significant importance in computer networking, similar to that of an IP address. It is also known as a physical, hardware, or burned-in address. It is a 12-digit hexadecimal number divided into six octets. The first three octets indicate the organization that issued the address, and the last three identify the specific device. MAC addresses direct data packets to the correct destination on a local network.

191

What is configuration management in networking and why is it important?

Reference answer

For this, network engineers and administrators use tools like Ansible, Puppet, or Chef to define the desired state of network devices and push configurations to devices, ensuring consistency and compliance. Automation reduces manual errors, speeds up deployment, and simplifies management across multiple devices.

192

What is a network security policy enforcement?

Reference answer

Network security policy enforcement involves implementing and enforcing security policies across the network. This includes configuring firewalls, intrusion detection systems, access controls, and other security measures to enforce the defined security rules and prevent unauthorized access or malicious activity.

193

Which layer of the OSI model is responsible for physical addressing, such as MAC addresses?

Reference answer

The Data Link layer (Layer 2).

194

How do VLANs improve security and performance?

Reference answer

A VLAN (Virtual Local Area Network) logically divides a single physical network into multiple broadcast domains. This allows you to group devices together regardless of their physical location. This segregation enhances both security and performance. VLANs improve security by isolating network traffic. For instance, you can separate traffic from different departments (e.g., finance, engineering) or types of devices (e.g., employee computers, IoT devices). This prevents unauthorized access to sensitive data. If one VLAN is compromised, the impact is limited to that specific VLAN, reducing the overall risk. VLANs also improve performance by reducing broadcast traffic within each segment. Since broadcasts are confined to their respective VLAN, less bandwidth is consumed, and network congestion is minimized. This leads to faster data transmission and better network responsiveness.

195

Which type of DNS query requires the DNS server to respond with either the requested resource record or an error message stating that the record could not be found?

Reference answer

A recursive DNS query requires the DNS server to respond with either the requested resource record or an error message stating that the record could not be found.

196

How do you perform a site survey for a wireless network?

Reference answer

A site survey involves analyzing the physical environment to determine the optimal placement of access points. It includes assessing signal coverage, interference sources, and network requirements using tools like spectrum analyzers and site survey software.

197

How do you handle IPv6 deployment in an enterprise network?

Reference answer

IPv6 adoption is essential for future-proofing networks. My strategy to handle IPv6 deployment in an enterprise network includes the following: - Address Planning: Structuring subnets efficiently using IPv6 addressing schemes. - Dual-Stack Implementation: Running IPv4 and IPv6 concurrently to allow gradual transition. - Security Considerations: Addressing new attack vectors such as rogue RA (Router Advertisement) threats. - Application Compatibility: Ensuring that legacy applications support IPv6. - Monitoring & Training: Deploying IPv6 monitoring tools and training teams on IPv6 best practices.

198

Name some wireless troubleshooting tools and their purposes?

Reference answer

Some wireless troubleshooting tools and their purposes are: - Wireshark: Packet capture for analyzing traffic. - Ekahau: RF survey and coverage mapping. - AirMagnet: Performance and interference analysis. - Cisco DNA Center: Centralized network monitoring, client performance tracking, and alerting.

199

Roaming Corporate workers need to access Corporate LAN Services like File server and Internal Portals. What solution should be proposed to meet this requirement?

Reference answer

A VPN (Virtual Private Network) solution should be proposed, such as an SSL VPN or IPSec VPN. This allows roaming workers to securely connect to the corporate network over the Internet, accessing file servers and internal portals as if they were on the LAN.

200

How do you use logs on WLC to troubleshoot client issues?

Reference answer

To troubleshoot client issues using WLC logs, check association and disassociation logs to view connection history, look for authentication or DHCP errors, and identify repeated failures that may indicate interference or misconfiguration. Logs can also be used to track roaming issues between APs and pinpoint performance problems.

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