Common Wi-Fi Engineer Interview Questions Explained

1

What is HTTPS, and what port does it use?

Reference answer

The big brother of HTTP, HTTPS stands for Secure HTTP (not to be confused with HTTPS, a separate protocol). HTTPS, which was created for identity verification, uses SSL certificates to confirm the server you are connected to is authentic. Although HTTPS has certain encryption capabilities, they are typically judged insufficient, and additional encryption methods are preferred whenever practical. TCP port 443 is used for HTTPS transmission.

2

What is the role of a load balancer in a cloud environment?

Reference answer

A load balancer distributes traffic across cloud instances, ensuring high availability and performance.

3

How do you handle network monitoring and alerting?

Reference answer

I handle network monitoring and alerting by implementing monitoring tools that provide real-time visibility into network performance and health. I configure alerts for critical events, such as device failures, traffic spikes, and security breaches. Regular review and analysis of monitoring data help identify potential issues early and ensure prompt response to any network anomalies.

4

What are the different types of networks?

Reference answer

Mainly there are four types of networks. These are: 1. Personal Area Network (PAN) The Personal Area Network (PAN) is considered to be the fundamental form of computer networking. This network is limited to an individual user, meaning that the exchange of information among computer devices is limited only to the user's personal workspace. The PAN technology allows communication between devices within a range of 1 to 100 meters from the user. The transmission speed is relatively high, and its maintenance is simple and cost-effective. 2. Local Area Network (LAN) LAN is a type of computer network that connects devices within a limited geographic area, such as a home, office, or school. LANs allow users to share resources, such as files, printers, and internet access, among the connected devices. One of the basic examples of Local Area Network (LAN) is a printer connected to a computer. The maximum range of the system is 1-10 kilometers, and its transmission speed is significantly high. 3. Metropolitan Area Network (MAN) The Metropolitan Area Network (MAN) is a network type that covers the network connection of an entire city or connection of a small area. The area covered by the network is connected using a wired network, like data cables. This network mainly uses FDDI, CDDI, and ATM as the technology, ranging from 5km to 50km. Its transmission speed is average. It isn't easy to maintain, and it comes with a high cost. 4. Wide Area Network (WAN) WAN is a network that connects devices over a large geographical area, such as different cities or countries. WANs typically use public or leased telecommunication lines to transmit data. Examples of WANs are the Internet, corporate networks, and satellite networks. In most cases, the connection is established through wireless means and relies on radio towers for transmission. WAN is a collection of Local Area Networks (LANs) that are connected with each other over a distance above 50 kilometers.

5

If my computer is connected to wireless LAN, can it communicate with computer on wired LAN as well?

Reference answer

- To do this you will need some sort of bridge between the wireless and wired network. This can be accomplished either with a hardware access point or a software access point. Hardware access points are available with various types of network interfaces, such as Ethernet or Token Ring, but typically require extra hardware to be purchased if your networking requirements change. - If networking requirements go beyond just interconnecting a wired network network to a small wireless network, a software access point may be the best solution. - A software access point does not limit the type or number of network interfaces you use. It may also allow considerable flexibility in providing access to different network types, such as different types of Ethernet, Wireless and Token Ring networks. Such connections are only limited by the number of slots or interfaces in the computer used for this task. - Further to this the software access point may include significant additional features such as shared Internet access, web caching or content filtering, providing significant benefits to users and administrators.

6

What is the purpose of Quality of Service (QoS) in network design?

Reference answer

QoS prioritizes certain traffic types (e.g., VoIP) to ensure bandwidth and low latency, improving performance for critical applications.

7

How do you implement QoS (Quality of Service) in a network?

Reference answer

I implement QoS by configuring network devices to prioritize certain types of traffic based on predefined policies. This involves setting up traffic classes, defining priority levels, and applying policies using techniques such as traffic shaping, queuing, and policing. QoS ensures that critical applications receive the necessary bandwidth and low latency, improving overall network performance and user experience.

8

Mention the different types of LAN cables used in networking. What do you mean by a cross cable?

Reference answer

Some of the common types of LAN cables that are used in networking are CAT 5 and CAT 6. CAT 5 provides 100 Mbps of speed and CAT 6 offers 1 Gbps of speed. However, the three major types of network cables are coaxial, fiber optic and twisted pair. A cross cable is also called a crossover cable that is used for connecting two similar devices for communication without the help of a hub or a switch.

9

How would you handle a difficult situation with a client?

Reference answer

First, I would express empathy and sincerely apologise for the client's unfortunate experience. My next step would be to actively listen to their concerns, asking relevant questions to gain a deeper understanding of the situation. I'd maintain a composed and respectful demeanour, even in the face of the client's anger or frustration. I would take full responsibility for the situation, set realistic expectations and propose a solution that addresses the client's needs and preferences. After resolving the issue, I would follow up with the client to ensure they were satisfied with the resolution and implement measures to prevent similar incidents in the future. Taking this comprehensive approach aims to foster positive client relationships and reinforce the commitment to exceptional service.

10

What are the differences between a hub, a switch, and a router?

Reference answer

A hub is a simple device that broadcasts all incoming traffic to every connected device, leading to collisions and poor performance. A switch learns MAC addresses and forwards traffic only to the intended recipient, improving efficiency. A router connects different networks and routes traffic based on IP addresses, enabling communication between networks and providing network segmentation.

11

What is a load balancer?

Reference answer

A load balancer distributes traffic across servers.

12

Describe your experience with configuring and managing firewalls.

Reference answer

Look for familiarity with firewall rules, access control lists, and common security protocols. Candidates should be able to explain how they would configure a firewall to protect a network from specific threats.

13

How would you describe network topology?

Reference answer

Network topology refers to the organisation of components within a communication network. This structural representation illustrates nodes, devices, and network connections, which can be physically or logically arranged to demonstrate their interrelationships. For example, in a mesh topology, every device within the network is directly interconnected with each other device, creating a comprehensive and redundant network structure. As a result, every device in the mesh topology must possess a minimum of two network connections to facilitate seamless communication and ensure reliable data transmission. Engineers can design and optimise networks by understanding topology to efficiently meet their intended purposes.

14

Walk me through how you would troubleshoot a network outage affecting multiple departments.

Reference answer

First, I'd gather information: Is it affecting all users or specific ones? Can they reach some resources but not others? This tells me whether it's a widespread outage or something more specific. Next, I'd check the monitoring tools we have in place—Nagios or SolarWinds—to see if there are any alarms firing. Then I'd check the core infrastructure. Is the main router up? Are the core switches passing traffic? If the core infrastructure looks healthy, I'd check departmental switches and access points. I also immediately start looking at recent changes—did someone deploy a new configuration or reboot a device? I remember one outage where it turned out a VLAN trunk port on a switch had been accidentally reconfigured. While I'm investigating, I'd communicate with the help desk about what I'm finding so they can manage user expectations. The key is being methodical rather than panicking and making it worse.

15

What's the most common issue you run into with regards to beamforming when looking at an overall wireless network?

Reference answer

The candidate should identify common beamforming issues, such as improper calibration, client compatibility, or coverage imbalances.

16

How do you troubleshoot network connectivity issues?

Reference answer

To troubleshoot network connectivity issues, I follow a systematic approach. First, I verify the physical connections and ensure that all cables and devices are properly connected. Next, I check the device configurations, including IP addresses, subnet masks, and gateway settings. I use diagnostic tools such as ping and traceroute to identify where the connectivity breaks down. I also review network logs and monitoring data to identify any errors or anomalies. If necessary, I escalate the issue and collaborate with other network engineers to resolve it.

17

What is the data rate of the 802.11g standard?

Reference answer

- Up to 54Mbps.

18

What are trunk ports and access ports?

Reference answer

A trunk port carries multiple VLANs.

19

How does an access point's transmit power affect network coverage?

Reference answer

Higher transmit power extends the coverage area of an access point, allowing it to reach more devices and cover a larger space. However, excessive power can lead to interference with other networks and reduce overall performance.

20

What is IPX?

Reference answer

IPX, or Internetwork Packet Exchange, was a fairly lightweight protocol, which was advantageous given the limitations of computers at the time. It is a TCP/IP rival that performs admirably in small networks, has little to no configuration, and does not require components like DHCP. However, it does not scale effectively for applications like the Internet. As a result, it was abandoned and is no longer a necessary protocol for the majority of pieces.

21

How do you prioritize and manage multiple tasks in a networking environment?

Reference answer

I use ticketing systems, assess impact, and address critical issues first while documenting progress.

22

What is the purpose of a CDN in cloud networking?

Reference answer

A CDN accelerates content delivery from cloud services by caching data at edge locations.

23

What are the important topologies for networks?

Reference answer

There are three important topologies for networks: BUS topology: Each computer in a BUS architecture connects to a single line of principal network cables. It's affordable and simple to set up, comprehend, and extend. STAR topology: A single hub connects every system, making it easy to troubleshoot and reinstall. RING topology: A single computer connects to two other computers from the rear and front ends. When all computers connect, they form a ring-like structure. This ensures equal access to network resources for all computers and less signal degradation compared to other topologies.

24

What is the frequency range of the 802.11a standard?

Reference answer

5GHz Frequency.

25

What is a firewall?

Reference answer

A firewall is a network security device that supervises traffic entering and leaving a network. Its primary purpose is to create a barrier between the internal network and external sources to avoid malicious traffic, like viruses or malware.

26

What is Quality of Service (QoS) in wireless networks?

Reference answer

QoS refers to the prioritization of certain types of traffic or users in a wireless network to ensure reliable service, especially for latency-sensitive applications like voice and video. It is achieved through traffic management, resource allocation, and scheduling.

27

Explain the function of the H.323 protocol.

Reference answer

H.323 is a standard for multimedia communication over IP, including VoIP and video conferencing.

28

Explain the purpose of Wireshark in network troubleshooting.

Reference answer

Wireshark captures and analyzes network packets in real-time, helping identify issues like latency, errors, or malicious traffic.

29

What is a firewall and how does it work?

Reference answer

A firewall filters network traffic based on security rules, inspecting packets and blocking unauthorized access while allowing legitimate traffic.

30

What is the function of the 802.11n standard in wireless networking?

Reference answer

The 802.11n standard improves wireless network performance by introducing features like MIMO (Multiple Input, Multiple Output), channel bonding, and higher data rates. It enhances throughput, range, and reliability compared to previous standards.

31

What is DNS, and why is it employed? What do A and MX records mean?

Reference answer

Domain Naming Service, or DNS, is used to translate between names and IP addresses. While we can easily recall names, the computer can only understand numbers. Therefore, we give computers and websites names. When we use these names (such as yahoo.com), the computer converts the request to an IP address (a number) via DNS. - "A" record: This is a host record and maps a name to an IP address. It uses the DNS record of the Domain Name System (DNS) to obtain a name's IP address. - "MX" Record: MX, or mail exchanger records are required to identify the network's mail servers.

32

What is the purpose of DHCP?

Reference answer

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and other network configuration parameters to devices, simplifying network management.

33

How do you stay proactive in identifying and mitigating potential network vulnerabilities?

Reference answer

I perform regular vulnerability scans, patch systems, and review logs for unusual activity.

34

Explain the concept of NAT.

Reference answer

NAT (Network Address Translation) translates private IP addresses to a public IP address for internet access, conserving public IP addresses and providing a layer of security.

35

What Strategies Would You Use to Achieve Optimal Capacity, Performance, and Range of a WiFi 6/6E Network?

Reference answer

To optimize a WiFi 6/6E network, it's crucial to understand the network's demand and design the infrastructure accordingly. Utilizing 1024-QAM for better data transfer rates and coordinating the OFDMA correctly is crucial. Moreover, to achieve optimal range, the placement of equipment and proper use of high-frequency ranges, such as the 6 GHz band, will be a key strategy in the optimization of these networks.

36

In which OSI layer does a gateway typically operate?

Reference answer

Gateways typically operate at the network layer, though they can function across multiple layers depending on their configuration. They connect networks using different protocols, facilitating seamless communication between them. This versatility makes gateways a crucial component in heterogeneous network environments.

37

Can you explain the DSSS, CCK and OFDM modulation schemes?

Reference answer

This question assesses your knowledge of how data is encoded for wireless transmission. Managers want to see that you understand the evolution of these schemes and their roles in different 802.11 standards. Provide a high-level explanation of each scheme, differentiating between them.

38

How can you configure Wi-Fi network and what are Wi-Fi Protocols?

Reference answer

1) Basically there are many standards of Wi-Fi in the industry but some popular of them are 802.11a, 802.11b, 802.11g/n. With the support of these Wi-Fi protocols we can communicate/interact among the devices at the speed of 5Ghz to 2.4Ghz dual band communication. 2) If we have Wi-Fi nic card so firstly we have to install their drivers and after installation if we have Wi-Fi access point then we can see the signal strength in the right corner below just open that and find the access point to connect, if access point is configured with the security, type the key to connect and enjoy the service. 3) Wi-Fi is technically referred to as the 802.11 protocol. Over time, Wi-Fi has improved, giving rise to different variations of the protocol. 802.11a – This version operates at 54Mbps. It is considered as the favorite wireless LAN protocol for IP telephony.

39

Explain the TCP three-way handshake in detail.

Reference answer

Before getting into the detailed answer, first remember these 3 words: SYN, SYN-ACK, ACK. Talking about TCP. Before any data is sent ove to TCP, the client and server are expected to make sure that the connection is reliable. In this case, TCP uses a three-way handshake method where it establishes a connection where both sides are ready to send and receive data. Here's how it goes: 1. A client, say your browser wants to connect to a server. It starts by sending a SYN packet. Along with this, it includes an initial sequence number basically saying, “I want to start a connection, and here's where my data numbering begins.” 2. The server receives this and responds with a SYN-ACK. Two things take place here, it acknowledges the client's sequence number and also sends its own sequence number back. 3. Now the client sends a final ACK, confirming that it received the server's sequence number. 4. At this point, the connection is established, and data transfer can begin. You might wonder why 3 steps are required here instead of 2 And it is because both sides need to confirm two things, and that is if they can send and receive. With only two steps, the server wouldn't know if the client actually received its response. Once communication is done, the connection is closed using a four-step process, i.e, FIN - ACK - FIN - ACK, which is slightly more involved. Here's what you might get asked during the interviews for a follow-up: Q. What happens if the SYN-ACK is lost? Your Ans: The client waits for a timeout and then retransmits the SYN packet. Q. What is a SYN flood attack? Your Ans: It's when an attacker sends a large number of SYN requests but never completes the handshake. This leaves connections half-open and can exhaust server resources.

40

How to send unicast probe request? Which field is set?

Reference answer

Unicast Probe Request: i) Destination address is ff:ff:ff:ff:ff:ff and SSID field is set to target AP's SSID. Or ii) Destination address is set to target AP's MAC address and SSID field is set to target AP's SSID. Unicast probe request SSID field is always set to target AP's SSID.

41

How does a wireless mesh network work?

Reference answer

A wireless mesh network consists of multiple access points that communicate with each other to form a self-healing, redundant network. Each AP acts as a node that relays data, extending coverage and improving network resilience.

42

What do you mean by a point to point link?

Reference answer

A point to point link is a connection between two dedicated networking devices. The complete bandwidth of the link is utilized for the transmission of data between two devices. There may be multiple connections between devices. Using a PPP link, two different networks can be connected, where one network will work as the endpoint for another. These days PPP links are created using modems and PSTN (Public Switched Telephone Networks). An example of a PPP link is a telephone call between two people.

43

What is the purpose of SIP in VoIP communication?

Reference answer

SIP (Session Initiation Protocol) sets up, manages, and terminates voice and video calls over IP networks.

44

What kinds of transmission media are available?

Reference answer

Two transmission media are available: guided and unguided. Guided Media, such as twisted-pair, coaxial cable, and fiber-optic cable, act as a conduit from one device to another. Any of these media's physical boundaries direct and confine a signal as it travels along them. Metallic materials that accept and transport signals in the form of electrical current are used in twisted-pair and coaxial cables. A glass or plastic cable called an optical fiber accepts and transmits signals in the form of light. Unguided Media is wireless media that transmits electromagnetic waves without a physical conductor. Signals can be sent through the air. Radio communication, satellite communication, and mobile telephony are used for this.

45

Describe the difference between Cisco Catalyst and Nexus switches.

Reference answer

Catalyst switches are for enterprise access, while Nexus switches are designed for data center environments with high performance.

46

Can you describe a time when you had to work with a cross-functional team to resolve a network issue?

Reference answer

In a previous role, we experienced a network outage that affected multiple departments. I worked with the IT, server, and application teams to identify the root cause, which was a misconfigured switch. Through collaborative troubleshooting, we resolved the issue, restored network connectivity, and implemented measures to prevent future occurrences. Clear communication and teamwork were essential to resolving the issue quickly and effectively.

47

What network engineering skills do you possess?

Reference answer

I 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.

48

You see packet drops in VoIP calls but bandwidth utilization is low. What will you check?

Reference answer

Check QoS policies → ensure RTP traffic is marked EF → verify queues and drops in show policy-map interface → confirm no microbursts on interface.

49

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.

50

What do you mean by a backbone network?

Reference answer

A backbone network is a network that has the connectivity infrastructure that is the main link for the various parts of a network. It has the capability of supporting networks spread over vast geographical areas. It can connect different networks within the same area or building, or different buildings within an area. Typically, a backbone network comprises routers, bridges, gateways, and switches.

51

What is a computer network?

Reference answer

A computer network is a group of interconnected devices that communicate and share resources with each other.

52

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.

53

Can you describe a time when you had to resolve a major network outage?

Reference answer

In a previous role, we experienced a major network outage due to a misconfigured core switch. The outage affected multiple departments and critical services. I quickly identified the issue by reviewing configuration changes and network logs. I reverted the misconfiguration, restored connectivity, and conducted a thorough analysis to prevent future occurrences. I also communicated with stakeholders to keep them informed and implemented additional monitoring to detect similar issues early.

54

What is Dynamic Transmit Power Control (DTPC)?

Reference answer

- DTPC: Adjusts transmit power of APs and clients to ensure balanced communication and save battery life.

55

How do you handle network compliance audits and assessments?

Reference answer

I handle network compliance audits and assessments by preparing comprehensive documentation, conducting internal reviews, and ensuring all security controls and policies are in place. During the audit, I work closely with auditors to provide necessary information and address any findings promptly. Continuous monitoring and regular internal assessments help maintain compliance and readiness for external audits.

56

What is Port Security?

Reference answer

Port Security restricts switch port access.

57

Describe how a Three-Way Handshake works in TCP/IP?

Reference answer

A three-way handshake is used in TCP/IP to establish a reliable connection between a client and a server. It begins with the client sending a SYN packet to the server, signaling a request to establish a connection. The server responds with a SYN-ACK packet, acknowledging the request. Finally, the client acknowledges the server's response with an ACK packet. After this, the connection is established.

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

Describe a Time You Implemented a Network Upgrade.

Reference answer

This question assesses project management and technical skills. Candidates should detail the planning, execution, and results of a network upgrade. Look for evidence of successful outcomes and lessons learned from challenges faced.

60

Describe a time you identified and resolved a wireless interference issue. What steps did you take?

Reference answer

At my previous position with Singtel, we faced significant interference issues in a densely populated area affecting our 4G network performance. I conducted a thorough site survey using spectrum analyzers to identify the source of the interference, which turned out to be from nearby commercial installations. By collaborating with the facilities management team, we adjusted the antenna orientation and implemented additional filtering solutions. This resolved the interference, resulting in a 30% improvement in signal quality and user satisfaction. This experience taught me the importance of cross-department collaboration.

61

How do you handle IP address allocation and management?

Reference answer

I handle IP address allocation and management by using DHCP (Dynamic Host Configuration Protocol) to automate the assignment of IP addresses within the network. For static IP addresses, I maintain a detailed IP address plan and document all allocations to ensure there are no conflicts. Additionally, I regularly review and update the IP address plan to accommodate network changes and expansions.

62

Difference between Wi-Fi and Bluetooth?

Reference answer

Wi-Fi vs Bluetooth: Wi-Fi is for high-speed internet access; Bluetooth is for short-range communication between devices.

63

How does beamforming improve wireless network performance?

Reference answer

Beamforming directs the wireless signal towards specific devices rather than broadcasting it in all directions. This focused signal improves signal strength, range, and data rates, resulting in better performance and reduced interference.

64

What is a mesh network, and how does it work?

Reference answer

A mesh network is a type of wireless network where devices (nodes) communicate directly with each other, forming a web-like structure. This creates multiple pathways for data to travel, increasing network reliability and coverage.

65

What is the role of a wireless network gateway?

Reference answer

A wireless network gateway serves as the interface between the wireless network and external networks (e.g., the internet). It manages traffic, provides security features like NAT (Network Address Translation), and may include firewall capabilities.

66

Explain the difference between TCP and UDP.

Reference answer

TCP (Transmission Control Protocol) is connection-oriented, reliable, and ensures ordered data delivery, while UDP (User Datagram Protocol) is connectionless, faster, and does not guarantee delivery or ordering.

67

How do you configure a wireless access point for optimal performance?

Reference answer

To configure an access point for optimal performance: - - Set appropriate channel and channel width. - Adjust transmit power to balance coverage and interference. - Implement band steering to distribute clients between 2.4 GHz and 5 GHz bands. - Regularly update firmware and monitor network performance.

68

What is DNS and how does it resolve domain names?

Reference answer

DNS (Domain Name System) translates domain names into IP addresses, allowing users to access websites easily.

69

Differentiate between a hub, switch, and router.

Reference answer

A hub operates at Layer 1 and broadcasts data to all ports, a switch operates at Layer 2 and forwards data based on MAC addresses, and a router operates at Layer 3 and routes packets based on IP addresses.

70

What is the role of the Certified Information Systems Security Professional (CISSP) in networking?

Reference answer

CISSP covers security management, including network security policies and risk assessment.

71

How do you handle a situation where a network change request could potentially impact the entire organization?

Reference answer

I follow change management, test in a staging environment, and schedule during maintenance windows.

72

What is the significance of the Nyquist theorem in wireless communication?

Reference answer

The Nyquist theorem states that the maximum data rate for a noiseless channel is twice the bandwidth of the channel. It helps determine the minimum sampling rate required to avoid aliasing in digital communication systems.

73

What are the advantages of using a VPN?

Reference answer

Below are few advantages of using VPN: - VPN is used to connect offices in different geographical locations remotely and is cheaper when compared to WAN connections. - VPN is used for secure transactions and confidential data transfer between multiple offices located in different geographical locations. - VPN keeps an organization's information secured against any potential threats or intrusions by using virtualization. - VPN encrypts the internet traffic and disguises the online identity.

74

What is the role of network topology in device interconnection?

Reference answer

Network topology dictates what media you should use to interconnect devices and serves as a basis for selecting the materials, connectors, and terminations suitable for the configuration.

75

What are the differences between public and private IP addresses?

Reference answer

Public IPs are internet-facing; private IPs are for internal use.

76

Can you explain the Software-Defined Networking (SDN) concept and its benefits?

Reference answer

SDN separates the network control plane from the data plane. This allows for more flexible and programmable network management. Benefits include centralized control, increased network agility, and easier implementation of network-wide policies.

77

What is the purpose of the G.711 codec in VoIP?

Reference answer

G.711 is a codec that encodes audio at 64 kbps, offering high quality with low compression.

78

Have you led a team of engineers before?

Reference answer

The candidate should confirm their leadership experience, including team size, scope of projects, and management style.

79

How do you keep updated with network engineering trends?

Reference answer

I recognise that staying up-to-date with the latest network engineering trends, products, and technologies is essential to my career, especially given the rapid pace of the IT industry. To achieve this, I actively engage in various online professional groups where we exchange ideas and explore new concepts. I also stay informed by subscribing to multiple podcasts and attending an annual IT conference. Additionally, I try to enrol on the latest courses and certifications and complete them in my own time to keep my knowledge of network engineering up-to-date.

80

What is Anonymous FTP?

Reference answer

Anonymous FTP is a way of granting user access to files on public servers. Users allowed access to data on these servers do not need to identify themselves but instead log in as anonymous guests.

81

How do you define a Mac address?

Reference answer

It is the LAN card's 48-bit hardware address. The network adapter card typically keeps the MAC address in ROM, and it is distinct.

82

Describe the advantages and challenges of implementing VoIP in an organization.

Reference answer

Advantages include cost savings and flexibility; challenges include network dependency and security risks.

83

In MPLS network, one site is unable to reach another site. What steps will you take?

Reference answer

Check PE router VRF → verify route in BGP VPNv4 table → confirm label binding in LFIB → check LDP/RSVP sessions → ping/traceroute with mpls ping/mpls traceroute.

84

Explain the concept of a VPN.

Reference answer

A VPN (Virtual Private Network) creates an encrypted tunnel over a public network, ensuring secure remote access and data privacy.

85

How does ARP (Address Resolution Protocol) work?

Reference answer

ARP resolves IP addresses to MAC addresses.

86

After a firewall change, users cannot access a public application. How will you debug?

Reference answer

Check NAT translations (show xlate) → ACL rules → default route → packet-tracer (ASA) or flow-debug → rollback if misconfiguration found.

87

What is the 802.11n standard?

Reference answer

Also known as Wi-Fi 4, 802.11n was introduced in 2009. It operates in both 2.4 GHz and 5 GHz frequency bands and uses multiple-input multiple-output (MIMO) technology to achieve a maximum data rate of up to 600 Mbps. It provides improved range and is backward compatible with 802.11a, 802.11b, and 802.11g devices.

88

Describe a time when you had to troubleshoot a complex network issue and the steps you took to resolve it.

Reference answer

I used packet captures to identify a misconfigured ACL, then updated rules and verified connectivity.

89

Describe the difference between a Layer 2 and Layer 3 switch.

Reference answer

A Layer 2 switch forwards frames based on MAC addresses, while a Layer 3 switch can also route packets based on IP addresses, combining switching and routing functions.

90

What network engineering skills could you improve upon?

Reference answer

Although I have a deep knowledge of network engineering, I would like to improve on my ability to present and translate complex ideas and processes to non-technical shareholders in a way that they will understand and benefit from.

91

What is the purpose of a wireless repeater?

Reference answer

A wireless repeater extends the coverage area of a Wi-Fi network by receiving and retransmitting signals.

92

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.

93

What is the use of a proxy server?

Reference answer

Proxy servers are used for securing a network from external users who might want to intrude into the network. It makes a computer system virtually invisible to others. A proxy server has a list of harmful websites so that the main network is protected. When it receives a request, it collects the data from the target web server and processes it. The response is then forwarded to the user.

94

Can I mix wireless equipments from different vendors, elaborate on it?

Reference answer

- You can mix wireless equipments from different vendors, but the recommendation is that you should prefer only prescribed vendors, because most wireless networking hardware vendors support the 802.11 standard they can inter operate. However, we recommend verification as the standard is a fairly recent one, and does specify two different methods for wireless communications; Frequency Hopping (FH) and Direct Sequence Spread Spectrum (DSSS or DS), which are not interoperable. - When purchasing wireless networking hardware from separate vendors be sure to obtain guarantees from the vendors that the hardware will interoperate and follows the standards. - Within a short time we expect all new wireless cards, like ethernet cards, to become inexpensive, ubiquitous and totally interoperable. - Also of note is that the latest version of the standard defines 11mbps and 5.5mbps networking, with support for the older standard 1mbps and 2mbps speeds. This provides some compatibility with different or older equipment. Note that this new standard covers DS-type Networks, not FH types. - Software access points such as InterGate which uses the wireless interface of the host computer should have no compatibility issues with third party wireless hardware, as long as standards are followed. Typically wireless hardware is identified to the software as a network interface, and therefore can be used in the same way as any other network card. So you can choose them from different vendors but keeping these things in mind and then go ahead.

95

Can you explain the concept of VLANs and their benefits?

Reference answer

A VLAN, or Virtual Local Area Network, allows for logical segmentation of a network, improving security by isolating sensitive data. It also enhances performance by reducing broadcast traffic and managing network congestion more effectively.

96

What is NAT and what are its types?

Reference answer

NAT modifies IP information in packet headers to allow multiple devices to share a single public IP address. Types include PAT (many private IPs to one public IP).

97

Do You Have Any Experience with Spectrum Analysis of the 6GHz Band?

Reference answer

Given that WiFi 6E operates in the 6GHz band, it's crucial to understand its spectrum allocation and usage. Spectrum analysis of the 6GHz band can help in finding out most suitable channels for deployment, identifying interference sources, and ensuring optimal performance in WiFi 6E networks. While I am still accumulating experience in this area, deploying WiFi 6E in the 6GHz band offers promising opportunities to gain extensive expertise.

98

Can you discuss a time when you had to implement a new technology in a network? What challenges did you face?

Reference answer

In my previous role, I led the implementation of SD-WAN technology to enhance network performance and reliability. The main challenge was ensuring minimal disruption during the transition, which I managed by conducting thorough testing and phased deployment.

99

What are some common issues you watch for, and how do you resolve them?

Reference answer

Network engineers must ensure that network performance is running optimally without issues despite bottlenecks and threats of decreased performance. Potential employers want to know that you have the skills to identify these common issues and can act quickly to reduce any downtime. This question gives you a chance to talk about your previous work optimizing router protocols and implementing delivery solutions to fix system bottlenecks.

100

Describe a time you've used RFID technologies in your day-to-day management?

Reference answer

The candidate should provide an example of using RFID for asset tracking, inventory management, or location services, detailing the implementation and outcomes.

101

How do you explain network issues to someone who doesn't understand computers?

Reference answer

As a Network Engineer, you'll often have to describe technical issues to people who aren't familiar with the terminology. When this occurs, use layman's terms. Drawing diagrams can be extremely helpful when describing a problem and possible solutions.

102

What is LTE Advanced Pro?

Reference answer

LTE Advanced Pro (also known as LTE-A Pro) is an enhancement of LTE that introduces new features like higher-order carrier aggregation, massive MIMO, and advanced modulation techniques. It provides faster data rates and better performance compared to standard LTE.

103

What are the security concerns and measures for data protection at Wi-Fi hotspots?

Reference answer

Security concerns at Wi-Fi hotspots include eavesdropping and man-in-the-middle attacks. Measures for data protection include using VPNs, ensuring HTTPS connections, and avoiding sensitive transactions on public networks.

104

Explain the concept of WEP and its security vulnerabilities.

Reference answer

WEP (Wired Equivalent Privacy) is an outdated wireless security protocol with weak encryption, easily cracked due to static keys and IV reuse.

105

What does the physical layer do?

Reference answer

The physical layer performs the transformation from data bits to electrical signals and vice versa. This is where network devices and cable types are considered and configured.

106

What is a backbone network?

Reference answer

A backbone network is a centralized infrastructure created to provide several networks with varied routes and data. It also manages channel and bandwidth control.

107

Difference between Site-to-Site vs Remote Access VPN?

Reference answer

Site-to-Site connects office to office; Remote Access connects user to office via secure tunnels.

108

When 2 laptops wirelessly connected can communicate directly, what type of topology is created?

Reference answer

Full Mesh Topology (Ad-hoc Network): Each node is directly connected to all other nodes.

109

What is VPN?

Reference answer

VPN stands for Virtual private network. - It is considered VIRTUAL because it establishes a digital pathway, without needing a physical cable, between the user's device and the VPN server. - It is considered PRIVATE due to its ability to encrypt user data and conceal their Internet Protocol (IP) address. - It is considered a NETWORK due to its ability to connect various computing devices, namely the user's device and the VPN server. Virtual Private Networks simplify the transmission of all network traffic to a virtual network, thus allowing users to access local network resources remotely and bypass Internet censorship. The majority of operating systems have built-in VPN support. VPNs were initially designed to connect separate corporate networks over the internet securely or to provide remote access to a company's network.

110

What are the basic components of a wireless communication system?

Reference answer

The basic components include: Transmitter: Converts information into a signal for transmission. Receiver: Decodes the transmitted signal back into information. Channel: The medium (air, space) through which the signal propagates. Antenna: Facilitates the transmission and reception of signals.

111

What are the advantages of IPv6 over IPv4?

Reference answer

IPv6 offers larger address space, better security, simplified header, and autoconfiguration.

112

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

Reference answer

Parameters Include: SSID, RF, Channel authentication method.

113

Define the term OFDM.

Reference answer

OFDM stands for Orthogonal Frequency Division Multiplexing, which is also a multiplexing technique used in analog systems. In OFDM, a guard band is not necessary, and the spectral efficiency of OFDM is high, which negates FDM. Additionally, an individual data source connects all the sub-channels in it.

114

How do you stay current with developments in the wireless industry?

Reference answer

I actively follow industry leaders on LinkedIn and subscribe to Wireless Week and IEEE Communications Magazine to stay informed about innovations and trends. Additionally, I attend the annual Mobile World Congress and participate in webinars hosted by the IEEE. Recently, I completed a certification course on 5G technologies, which I've already started applying in my projects. I also share key takeaways with my team to foster a culture of continuous learning.

115

What is the main purpose of a DNS server?

Reference answer

DNS stands for Domain Name Server. It translates Internet domains and hostnames to IP addresses and vice versa. DNS technology allows typing names into your Web browsers and your computer to automatically find that address on the Internet. A key element of the DNS is a worldwide collection of DNS servers. It has the responsibility of assigning domain names and mapping those names to Internet resources by designating an authoritativename server for each domain. The Internet maintains two main namespaces like Domain Name hierarchy and Internet protocol address space.

116

What happens in the OSI model, as a data packet moves from the lower to upper layers?

Reference answer

In the OSI model, as a data packet moves from the lower to upper layers, headers get removed.

117

Explain the difference between static and dynamic routing.

Reference answer

Static routing involves manually configuring the routing table with fixed paths for data packets. It's simple and secure but requires manual updates when network changes occur. Dynamic routing uses algorithms and protocols like OSPF or EIGRP to automatically adjust paths based on network conditions. It adapts to changes more efficiently but may be more complex to manage.

118

What is Wi-Fi technology and over which frequency band it operates?

Reference answer

Wi-Fi technology is a technology used for transmitting a signal using the 802.11 specifications works a lot like it does with a basic Ethernet hub: They're both two-way forms of communication, and they both use the same frequency to both transmit and receive, often referred to a half-duplex. WLANs used radio frequencies (RFs) that are radiated into the air from an antenna that creates radio waves. These waves can be absorbed, refracted, or reflected by walls, water, and metal surfaces, resulting in low signal strength. So because of this vulnerability to surrounding environmental factors, it's pretty apparent that wire-less will never offer us the same robustness as a wired network can, but that still doesn't mean we're not going to use or run the wireless or Wi-Fi.

119

What is a gateway in networking?

Reference answer

A gateway is a network node that connects two different networks, often translating protocols and enabling communication between them.

120

Describe the benefits and drawbacks of a decentralized network architecture.

Reference answer

Benefits include resilience and scalability, while drawbacks involve complexity in management and security.

121

How do you stay current with emerging wireless technologies and ensure your designs are future-proof?

Reference answer

I actively follow publications like 'Wireless Week' and participate in online forums such as the IEEE Communications Society. I attend the annual Mobile World Congress to network and learn about emerging technologies. Recently, I completed a certification in 5G network design, which I applied to a current project to ensure our infrastructure is future-proof. Sharing insights with my team helps us innovate and stay competitive.

122

What is the role of Network Address Translation (NAT)?

Reference answer

Network Address Translation (NAT) enables private IP networks that use unregistered IP addresses to connect to the public internet. NAT operates on a router, usually connecting two networks together, and translates the private (not globally unique) addresses in the internal network into a legal public IP address before packets are forwarded on the internet. It helps conserve the global IP address space.

123

What is the purpose of a network management system (NMS)?

Reference answer

An NMS centralizes monitoring, configuration, and performance management of network devices.

124

Which frame has AID, Listen interval?

Reference answer

Association/Re-Association response frame contains AID. Association/Re-association request frame contains Listen Interval.

125

Explain the WLAN physical layer frame as per 802.11a?

Reference answer

WLAN has physical layer frame formats that differ in 11a, 11b, 11g, 11n, and 11ac. They all have three generic fields: preamble, header, and data payload (PSDU). The preamble carries STF (short training field) and LTF (long training field) used for front-end synchronization. Front-end synchronization includes time offset estimation and correction, frequency offset estimation and correction, and channel estimation and equalization. The header carries two important parameters: rate and length. Rate specifies the modulation-code rate of the data payload part, and the length field specifies the length of the data payload in units of OFDM symbols.

126

What Happens When You Type a URL in a Browser?

Reference answer

When you enter a URL like www.example.com, the following steps occur one by one: - DNS Resolution – The browser queries a DNS server to translate the domain name into an IP address. - TCP Connection – A TCP three-way handshake is established with the server. - HTTP/HTTPS Request – The browser sends an HTTP or HTTPS request to the web server. - Server Response – The server sends back the requested webpage data. - Rendering – The browser renders HTML, CSS, and JavaScript to display the page. Follow-up Question: Which protocol allows users to access a website using a URL instead of an IP address? DNS (Domain Name System) converts human-readable domain names (like google.com) into IP addresses that computers use to communicate. So, we do not need to know and write ip address of any website. We preferred easily remembered domain addresses.

127

What considerations are important when designing a secure network?

Reference answer

Implement firewalls, segmentation, encryption, access controls, and regular security audits.

128

What are the applications and scenarios where Ad-Hoc networking is preferable over infrastructure mode?

Reference answer

Ad-Hoc networking is preferable over infrastructure mode in scenarios like temporary meetings, emergency communication setups, or direct file sharing between devices without an existing network infrastructure.

129

How do TFTP and FTP application layer protocols differ?

Reference answer

A local host can download files from a distant host using the trivial file transfer protocol (TFTP), but it lacks security and reliability. It uses UDP's basic packet delivery functions. The usual method offered by TCP/IP for copying a file from one host to another is the File Transfer Protocol (FTP). It is dependable and secure because it uses TCP's services. It creates two links (virtual circuits) between the hosts, one for informational control and the other for data transport.

130

What data rates are beacons sent out / broadcasted?

Reference answer

Beacons are broadcasted at the mandatory data rates set on the 2.4 and 5GHz radios.

131

You are asked to migrate traffic from one PE router to another without downtime. How will you do it?

Reference answer

Use BGP path prepending/local-pref to shift routes gradually → verify MPLS/labels on new PE → move customers in phases → monitor for packet loss.

132

What is the difference between TCP and UDP?

Reference answer

TCP ensures reliable data transmission by establishing a connection. It uses acknowledgements to confirm data delivery. In contrast, UDP is faster but less reliable. UDP does not establish a connection or guarantee delivery. TCP is used for applications requiring accuracy. This includes things like file transfers or emails. But, UDP is better for real-time applications. It is often used for streaming or online gaming.

133

Can you share an experience where a major project did not meet its objectives and what you learned?

Reference answer

During a large-scale network upgrade, unforeseen compatibility issues delayed the project and affected performance. I conducted a thorough post-mortem analysis, which highlighted the need for more rigorous pre-deployment testing. This experience taught me the importance of contingency planning and stakeholder communication.

134

How can you optimize network performance for video streaming?

Reference answer

Use QoS, adaptive bitrate streaming, CDNs, and sufficient bandwidth to ensure smooth playback.

135

What is FlexConnect in Cisco Wireless?

Reference answer

FlexConnect: Enables branch office APs to be managed from a central location, allowing local client data switching and authentication. FlexConnect (previously known as Hybrid Remote Edge Access Point or H-REAP) is a wireless solution for branch office and remote office deployments. It enables you to configure and control access points in a branch or remote office from the corporate office through a wide area network (WAN) link without the deployment of a controller in each office. The FlexConnect access points (APs) can switch client data traffic locally and perform client authentication locally. When they are connected to the controller, they can also send traffic back to the controller.

136

Can You Explain a Complex Networking Concept to a Non-Technical Person?

Reference answer

Communication skills are vital for network engineers who often need to explain technical issues to non-technical stakeholders. Candidates should demonstrate the ability to simplify complex concepts without losing essential details.

137

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"

138

Can You Provide an Example of a Network Problem You Solved?

Reference answer

This question reveals problem-solving skills and technical expertise. Candidates should describe a specific issue, the steps taken to resolve it, and the outcome. Look for a structured approach and successful resolution.

139

Explain the differences between stateful and stateless autoconfiguration in IPv6.

Reference answer

Stateful uses DHCPv6 for addresses, while stateless (SLAAC) uses router advertisements for automatic configuration.

140

What does the term Quality of Service (QoS) mean in networking?

Reference answer

In networking, Quality of Service (QoS) refers to the performance level of a service or network. QoS mechanisms control the bandwidth, delay, jitter, and packet loss rate in a network by prioritizing certain types of traffic. For instance, voice and video traffic may be prioritized over other types of traffic to ensure smooth communication.

141

Describe the differences between a hub and a switch.

Reference answer

A hub broadcasts to all ports, while a switch forwards based on MAC addresses, reducing collisions.

142

What is DNS?

Reference answer

DNS is known as the phonebook that helps in translating the domain into a computer-readable IP address. DNS allows users to access websites without having to memorize long strings of numbers. For example, instead of typing 104.26.10.228, you can type pynetlabs.com, and DNS will find your corresponding IP address.

143

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

Reference answer

SNMP (Simple Network Management Protocol) monitors and manages network devices by collecting metrics and sending alerts.

144

Describe the benefits of network virtualization in cloud environments.

Reference answer

Benefits include resource efficiency, rapid provisioning, and multi-tenant isolation.

145

What is the purpose of the CompTIA Network+ certification?

Reference answer

Network+ validates vendor-neutral networking skills, covering troubleshooting and configuration.

146

What are the messages exchanged between STA and AP in WLAN? Explain the function of each.

Reference answer

There are various messages exchanged between a Station (STA) and an Access Point (AP) in a WLAN network for various purposes, such as establishing a connection, data transfer, terminating the connection, and more. Access points are devices that help extend wired networks with wireless capabilities. The main WLAN MAC messages are listed below with their main functions. - Association request: This is sent by STA to AP to obtain association after authentication is done. - Association response: This message is sent by AP in response to the received association request. - Probe request: It is used to find out AP in the WLAN network. - Probe response: It contains station (STA) parameters as well as data rates. - Beacon: It is used by AP to announce the start of a CF (Contention Free) period. - Disassociation: Used to announce the break-up of an existing association between peers in a WLAN network. - Authentication: These packets are used by STA to request authentication. - De-Authentication: Used by an authenticated station to announce that the receiver no longer needs to be authenticated. - RTS/CTS: Used for the initial handshake between WLAN peers. - ACK: Indicates the receipt of transmitted data whether reached on the other side or not. - CF end: It indicates the end of CFP (contention-free period).

147

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

148

Describe a challenging networking problem you faced and how you resolved it.

Reference answer

Example: A routing loop caused outages; I used traceroute and STP analysis to identify and disable redundant links.

149

How do tunnels work in network communication?

Reference answer

Tunnels create a virtual passage for data exchange between two communicating computers without using IPsec themselves. The gateway connecting their LANs to the transit network creates a virtual tunnel and uses the IPsec protocol to secure all communication passing through it.

150

How do you ensure network security, especially in an environment with increasing threats?

Reference answer

Network security is multi-faceted, requiring both perimeter and in-depth strategies. I implement firewalls to block unauthorized access and use Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) for real-time threat detection and mitigation. Beyond hardware solutions, I believe in maintaining a strong security posture through regular patching, security audits, and end-user education. For monitoring, tools like Wireshark and SolarWinds provide invaluable insights into network traffic, enabling early detection of anomalies.

151

What Is BSOD? How can you fix your computer if it has a blue screen?

Reference answer

BSOD stands for "Blue Screen of Death." A blue screen with a code appears when a hardware or OS issue prevents the Windows operating system from functioning. The best solution is to boot from the "Last Known Good Configuration" on the PC. Boot the machine in safe mode. And if that doesn't work, it could signify issues with the devices or driver.

152

When 2 laptops wirelessly connected can communicate directly, what type of topology is created?

Reference answer

- Full Mesh Topology (Ad-hoc Network): Each node is directly connected to all other nodes.

153

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.

154

Define piggybacking?

Reference answer

Piggybacking is used to improve the efficiency of the bidirectional protocols. When a frame is carrying data from A to B, it can also carry control information about arrived (or lost) frames from B; when a frame is carrying data from B to A, it can also carry control information about the arrived (or lost) frames from A.

155

Can You Describe Your Understanding of 6 GHz WiFi (WiFi 6E) And Its Benefits?

Reference answer

WiFi 6E essentially means 'Extended,' and represents WiFi 6's extension into the 6 GHz band. This higher frequency band, previously reserved for other forms of communication, like satellite and telecom, offers additional channels and lesser noise. Consequently, WiFi 6E enjoys all the benefits of WiFi 6 and additional, less congested bandwidth to provide faster speeds and lower latency. This is particularly advantageous for high-performance uses such as gaming and HD video streaming.

156

What is the signal-to-noise ratio (SNR), and why is it important?

Reference answer

SNR is the ratio of the signal power to the noise power. A higher SNR indicates a clearer, stronger signal. It is important because it determines the quality of the communication link and directly affects data transmission rates and error rates.

157

What is a USB?

Reference answer

USB stands for Universal serial bus, which connects devices like modems, mouses, and keyboards.

158

Which devices can interfere with wireless network operation?

Reference answer

- Interfering Devices: Microwave ovens, cordless phones.

159

Can you describe your experience with network automation and scripting?

Reference answer

I have experience with network automation and scripting using tools like Ansible, Python, and PowerShell. This includes automating routine tasks such as device configuration, software updates, and network monitoring. Automation improves efficiency, reduces errors, and allows for more consistent network management. I also develop custom scripts to address specific network needs and streamline operations.

160

What is an Anycast address?

Reference answer

Anycast address is a single IP address utilized by a set of servers at different sites. When one directs any request to an Anycast address, the address is redirected to the nearest server. This will improve the speed and consistency of network services since the distance the information needs to travel is reduced. It is also able to help manage heavy traffic at the same time. How it works: - The same IP address is used for many servers. - The network finds the closest server to you. - Your request is sent to that server automatically. - If one server fails, traffic is redirected to the next closest server.

161

Can you describe your experience with network analytics and reporting?

Reference answer

I have experience with network analytics and reporting using tools like SolarWinds, PRTG, and Splunk. These tools provide insights into network performance, traffic patterns, and security events. I generate regular reports to monitor key metrics, identify trends, and make data-driven decisions to optimize network operations and improve performance.

162

How does SDN (Software-Defined Networking) relate to network virtualization?

Reference answer

SDN provides centralized control for virtualized networks, enabling dynamic policy management.

163

What is WAN?

Reference answer

WAN is a Wide Area Network. It connects computers across different places or countries.

164

How many MCS rates are there for 802.11ac?

Reference answer

There are nine for a specific Spacial stream. http://wirelessonthego.postach.io/post/802-11ac-mcs-rates

165

Explain the concept of a virtual LAN (VLAN).

Reference answer

A VLAN logically segments a network into isolated groups, improving security and reducing broadcast traffic.

166

Describe How WiFi 6/6E Implementations Can Improve IoT Application Performance?

Reference answer

Wi-Fi 6/6E's advantages like higher data rates, improved capacity, lower latency, and advanced power management features make it favorable for IoT applications. IoT devices often require reliable connectivity, and WiFi 6/6E's ability to accommodate many devices simultaneously can optimize the performance of the entire IoT network. Furthermore, features such as Target Wake Time (TWT) can significantly improve the battery life of IoT devices.

167

What is Piggybacking in the context of Wi-Fi?

Reference answer

Piggybacking: Unauthorized use of someone else's wireless connection without their permission.

168

One of your core routers is showing high CPU usage and customer traffic is impacted. How will you troubleshoot?

Reference answer

Check show processes cpu to identify the culprit → verify control plane vs data plane issue → check routing protocol flaps, BGP churn, or ACL processing → if DoS attack suspected, use CoPP (Control Plane Policing).

169

What is NIC?

Reference answer

NIC stands for network interface controller — a piece of computer hardware also known as a network card or network adapter. An NIC enables computer communication over a computer network.

170

How do you verify whether a network port is open?

Reference answer

I use tools like Nmap or Telnet to scan and verify open ports on a network. These tools help identify which ports are accessible and monitor potential vulnerabilities. Regular port checks are a key part of maintaining network security and performance.

171

What do fully qualified and partially qualified domain names mean?

Reference answer

- Fully Qualified Domain Name A fully qualified domain name (FQDN) ends with a null or empty string (FQDN). - Partially Qualified Domain Name A partially qualified domain name does not end with a null string (PQDN). A PQDN does not finish at the root; rather, it begins at a node.

172

Explain the function of ICMP.

Reference answer

ICMP (Internet Control Message Protocol) is used for error reporting and diagnostic functions, such as ping and traceroute, in IP networks.

173

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

174

How does Ultra-Wideband (UWB) contrast with Wi-Fi in terms of bandwidth and application differences?

Reference answer

Ultra-Wideband (UWB) contrasts with Wi-Fi by offering very high bandwidth over short distances, making it suitable for applications like precise location tracking and high-speed data transfer in close proximity, while Wi-Fi provides broader coverage and is used for general wireless networking over longer ranges.

175

How do you approach network capacity planning?

Reference answer

I approach network capacity planning by analyzing current network usage and performance metrics, projecting future growth, and identifying potential bottlenecks. This involves monitoring traffic patterns, evaluating bandwidth requirements, and assessing the scalability of existing infrastructure. Based on the analysis, I develop a plan that includes upgrading hardware, optimizing configurations, and implementing additional resources to ensure the network can handle future demands.

176

Describe the challenges of securing virtualized networks.

Reference answer

Challenges include visibility gaps, hypervisor vulnerabilities, and east-west traffic security.

177

How do you work with a development team?

Reference answer

Interestingly, most infrastructure and development teams don't get along well with each other. When development teams and infrastructure teams get together to design large systems, they usually disagree with each other. There can be a lot of tension between the two departments. When you answer this question, make sure you give an answer that attempts to help a development team and facilitates progress instead of stifles it. You want to help developers complete projects while securing the network in the best way possible.

178

What is the network topology?

Reference answer

Network topology is a physical layout of the network, connecting the different nodes using the links. It depicts the connectivity between the computers, devices, cables, etc.

179

What is the purpose of VLAN?

Reference answer

VLANs (Virtual Local Area Networks) segment networks to improve performance and security. They achieve this without the need for new hardware. They allow logical grouping of devices regardless of physical location.

180

Have You Worked with Any Specific Hardware Vendors for WiFi 6/6E Access Points?

Reference answer

Several vendors offer WiFi 6/6E hardware, including popular names like Cisco, Netgear, Asus, and TP-Link. Through past projects, I had opportunities to work with different vendors, each providing a unique experience. For instance, Asus and Netgear have user-friendly interfaces that make the setup process effortless, whereas Cisco provides more robust and enterprise-level features that suit large organizations.

181

How does a wireless repeater work, and when would you use one?

Reference answer

A wireless repeater receives and retransmits wireless signals to extend coverage in areas with weak signal strength. It is used to enhance signal coverage in large or obstructed areas, improving connectivity for devices at the network's edge.

182

What steps do you take to ensure network security?

Reference answer

I implement layered security measures including firewalls, intrusion detection systems, and regular vulnerability assessments. I also enforce strict access controls and continuously monitor network traffic for anomalies. By staying current with security patches and industry trends, I maintain a robust defense against cyber threats.

183

What skills do you have with cloud networking?

Reference answer

Cloud-based networking allows organizations to use virtual networks with a third-party provider to handle network computing rather than operating an expensive in-house network. This is a good chance to discuss your skills with different cloud network environments, including certifications you may have earned that demonstrate your proficiency with these cloud platforms. Some of these certifications include: AWS Certified Cloud Practitioner, Microsoft Certified: Azure Fundamentals, Google Cloud Certification.

184

What is a Router?

Reference answer

A router routes data between networks.

185

Models of Outdoor Rugged Access Points/Bridges?

Reference answer

- Models Include: Aironet 1530, 1540, 1560, 1570, 1552, and Industrial Wireless 3702. Below are some of the latest Cisco Outdoor Rugged Access Points - Aironet 1530 Series Aironet 1540 Series Aironet 1560 Series Aironet 1570 Series Aironet 1552 Access Point Industrial Wireless 3702

186

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.

187

How would you design a scalable and redundant network architecture?

Reference answer

I would implement a modular design with core, distribution, and access layers. This includes using redundant links and devices, implementing load balancing, choosing scalable technologies like VLANs and IP subnets, and ensuring the network can accommodate future growth in users, devices, and applications.

188

What is a proxy server? Forward proxy vs reverse proxy.

Reference answer

A proxy server acts as an intermediary/middlemam between a client and a server. I So what happens is that direct communication doesn't take place, and a request is passed through the proxy, which is then forwarded to the destination intended. Now, proxy works differently depending on where it is placed. And this can be understood through forward and revers proxies. I'll first explain this to you with a simple idea. Normally, a request goes from a client to server. But when a proxy is introduced, the client first nudges the proxy and then it reaches the server. In Forward Proxy, the proxy sits in front of the client. So the request flow goes from client to the forward proxy and then the internet. And because of this, the server doesn't really see the client's IP address instead it only confronts the proxy. So, wherever websites are needed to be controlled, like in the corporate setting, the forward proxy is used. It can also be used for caching or hiding user identity. Now talking about Reverse Proxy Consider the opposite case. Here, the proxy sits in front of the server and because of that the flow goes from client to the revers proxy and then the server. From the client's point of view, it looks like they are communicating with a single server, but internally, the proxy may be routing the request to multiple backend servers. This setup is usually used for load balancing, SSL handling, and protecting servers from direct exposure. In the most basic sense, what you should remember is that forward proxy is used on the client's side to hide client's identity and a revers proxy is used on the server side which hides the server's identity. Some examples that you can use are: - Forward proxies are often used in corporate firewalls. - Reverse proxies are commonly used with tools like Nginx or services like Cloudflare.

189

What is COBIT?

Reference answer

COBIT® is a framework for developing, implementing, and monitoring information technology and management practices. It is a framework by ISACA (Information System Audit and Control Association) designed for all IT governance to bridge the gap between technical issues, business risk, and control requirements.

190

What is the difference between TCP and UDP?

Reference answer

191

What do you mean by a node?

Reference answer

A node is a point where two or more devices connect within a network. A node is where data is received, stored, sent and created within the network. Nodes can be an endpoint for transmitting data or a redistribution point. Any device connected to another device inside a network is a node itself. Common examples of nodes are switches, routers, bridges, and servers, which may be connected or other devices through the internet.

192

Explain LAN (Local Area Network)

Reference answer

LANs are widely used to connect computers/laptops and consumer electronics which enables them to share resources (e.g., printers, fax machines) and exchange information. When LANs are used by companies or organizations, they are called enterprise networks. There are two different types of LAN networks i.e. wireless LAN (no wires involved achieved using Wi-Fi) and wired LAN (achieved using LAN cable). Wireless LANs are very popular these days for places where installing wire is difficult. The below diagrams explain both wireless and wired LAN.

193

What sets apart Arp from Rarp?

Reference answer

A host or router can utilize the address resolution protocol (ARP), which determines the physical address of another host on its network by sending an ARP query packet with the recipient's IP address. When a host just knows its physical address, the reverse address resolution protocol (RARP) enables it to find its Internet address.

194

Describe the differences between FTP and SFTP.

Reference answer

FTP transfers files without encryption, while SFTP uses SSH for secure file transfer.

195

What bracket of network engineer salary are you looking for?

Reference answer

Based on my level of experience as a network engineer and research I have conducted around the position you're offering, I would be grateful for you to offer me 'X' for this position.

196

What is SNR? How do you fix SNR issues?

Reference answer

SNR (Signal-to-Noise Ratio) measures the strength of the wireless signal relative to background noise. To fix SNR issues, techniques include reducing interference, adjusting antenna placement, or increasing signal power.

197

Explain the significance of the Certified Ethical Hacker (CEH) certification in network security.

Reference answer

CEH teaches ethical hacking techniques to identify and mitigate network vulnerabilities.

198

What is the master controller mode on WLC?

Reference answer

- Master Controller Mode: Designates a controller as the tie-breaker when multiple controllers are available.

199

What is the role of a PBX in VoIP systems?

Reference answer

A PBX (Private Branch Exchange) manages internal call routing and connects to external phone networks.

200

Difference between UWB and Wi-Fi?

Reference answer

UWB vs Wi-Fi: UWB is short-range and high-bandwidth, ideal for personal area networks; Wi-Fi is longer-range and suitable for local area networks.

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