Basic to Advanced Wi-Fi Engineer Interview Questions

1

Explain the difference between TCP and UDP, and give examples of when you'd use each.

Reference answer

TCP is reliable and connection-oriented—it establishes a connection, ensures packets arrive in order, and resends anything that gets lost. UDP is connectionless and fires packets without caring if they arrive. TCP is what you use for file transfers, email, and web traffic where you can't afford to lose data. UDP is what you use for video streaming or VoIP where speed matters more than perfection—losing a few packets of voice or video is better than having a frozen connection. I've worked with both in monitoring scenarios. When I set up Nagios monitoring, it uses TCP to check if services are responding because missing an alert is worse than a slight delay. But when we set up IP telephony, we used UDP because users would rather have a brief audio glitch than wait for retransmissions.

2

Two PCs are in the same VLAN but cannot communicate. What could be the issue?

Reference answer

Here is a list of possible reasons: - Incorrect subnet mask - The host firewall is blocking traffic - Duplicate IP addresses - Switch port security restrictions - One port accidentally assigned to another VLAN - NIC issues Here's how you can solve it: - First, you should verify IP configurations - Then, check VLAN membership - Ping both devices - Check the ARP table - Inspect switch configuration

3

Describe the role of syslog in network management.

Reference answer

Syslog aggregates log messages from devices for troubleshooting and security auditing.

4

What is the difference between NAT and PAT?

Reference answer

Network Address Translation (NAT) translates one public IP address to one private IP address, allowing devices on a private network to access the internet. Port Address Translation (PAT), a type of NAT, translates one public IP address to multiple private IP addresses by using port numbers to distinguish between different connections. PAT is commonly used in home and small office networks, allowing multiple devices to share a single public IP address provided by the ISP. It conserves public IP addresses and enhances security by hiding the internal network structure.

5

Describe the TCP/IP Reference Model

Reference answer

It is a compressed version of the OSI model with only 4 layers. It was developed by the US Department of Defence (DoD) in the 1980s. The name of this model is based on 2 standard protocols used i.e. TCP (Transmission Control Protocol) and IP (Internet Protocol).

6

Name two technologies by which you would connect two offices in remote locations.

Reference answer

Two technologies that would connect two offices in remote locations are VPN and Cloud computing.

7

What is the role of wireless network planning tools?

Reference answer

Wireless network planning tools help design and optimize wireless networks by simulating coverage, analyzing signal strength, and identifying potential interference. They assist in determining access point placement and network configuration for optimal performance.

8

What is your experience with wireless networks?

Reference answer

The candidate should describe their past experience in wireless network engineering, including specific roles, projects, and technologies they have worked with.

9

What is beamforming, and how is it used in wireless systems?

Reference answer

Beamforming is a signal processing technique that focuses the wireless signal in a specific direction rather than broadcasting it omnidirectional. This improves signal strength and quality, especially in MIMO systems like 5G.

10

What is Bandwidth?

Reference answer

Bandwidth is a measurement that indicates the highest possible data transmission capacity of a wireless or wired communication channel within a network connection during a specific time frame. Higher bandwidth means more data can be sent and received faster and with fewer errors.

11

Describe the purpose of the show ip route command.

Reference answer

This command displays the routing table, showing known networks and next-hop addresses.

12

How does DHCP work?

Reference answer

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and configurations to devices in a network.

13

What is the OSI model?

Reference answer

The OSI model is a 7-layer conceptual framework describing network communication. From top to bottom: Application (network services for apps), Presentation (data formatting and encryption), Session (communication sessions), Transport (reliable/unreliable delivery via TCP/UDP), Network (routing and IP addressing), Data Link (physical addressing and media access control), Physical (cables, connectors, and electrical signals).

14

What is the Wi-Fi protocol based on IEEE 802.11 and its significance in wireless communication?

Reference answer

The Wi-Fi protocol based on IEEE 802.11 is a set of standards for wireless local area networking. Its significance lies in enabling reliable and interoperable wireless communication between devices, allowing for high-speed data transfer and network connectivity.

15

How do you start troubleshooting a wireless network issue?

Reference answer

The candidate should describe a systematic approach, such as gathering data, analyzing logs, checking physical components, and using diagnostic tools.

16

What is the significance of the enable secret command?

Reference answer

It sets an encrypted password for privileged EXEC mode, enhancing security over enable password.

17

How Do You Collaborate with Other IT Teams?

Reference answer

Network engineers often work with other IT professionals. Candidates should discuss their experience in cross-functional teams, emphasizing communication and teamwork skills. A good answer will highlight successful collaborations and the ability to work towards common goals.

18

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.

19

How would you describe what anonymous FTP is?

Reference answer

Anonymous 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 they'll log in as anonymous guests.

20

TCP handshakes, TCP Windowing

Reference answer

You can google it :)

21

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.

22

What is ACL?

Reference answer

ACL (Access Control List) is a packet filtering rule set.

23

Do you have any experience managing WLAN security?

Reference answer

The candidate should detail their experience with WLAN security measures, such as encryption standards, authentication methods, and intrusion detection.

24

What is SSH?

Reference answer

SSH, or Secure Shell, is most popular among Linux users but has a wide range of applications. Systems, switches, thermostats, or toasters, may all be connected securely over a tunnel, thanks to SSH. SSH also offers the unique ability to act as a tunnel for other programs, which is conceptually comparable to a VPN. If configured properly, even insecure programs or programs operating via insecure connections can be used in a secure state.

25

How do you approach documentation for network configurations and changes?

Reference answer

I use standardized templates to ensure consistency and clarity in documentation. Each configuration is accompanied by detailed descriptions and diagrams, and I regularly update the documentation to reflect any changes or improvements.

26

What are manageable and unmanageable switches?

Reference answer

Manageable switches are customizable, configurable, and controllable. Unmanageable switches don't have any customizable or configurable settings.

27

What is the OSI reference model?

Reference answer

OSI stands for Open System Interconnection and defines the communication of applications on a network. The OSI model helps you understand the relationship between existing networks and defines how networks communicate.

28

What is network segmentation, and why is it critical in large enterprises?

Reference answer

Network segmentation involves partitioning a larger network into smaller, isolated segments to enhance performance and security. It limits broadcast traffic, reduces the risk of widespread breaches, and improves overall management. In my projects, segmentation has proven invaluable for maintaining high performance in complex network environments.

29

Can you explain the difference between IPv4 and IPv6?

Reference answer

IPv4 (Internet Protocol version 4) uses a 32-bit address format, allowing for approximately 4.3 billion unique addresses. IPv6 (Internet Protocol version 6) uses a 128-bit address format, providing a vastly larger address space. IPv6 also includes improvements such as simplified header structure, improved security features, and support for auto-configuration. IPv6 was developed to address the limitations of IPv4, including address exhaustion and the need for more efficient routing.

30

How do you approach the configuration and management of cloud-based networks?

Reference answer

I begin by assessing the specific requirements of the cloud environment and selecting the appropriate networking solutions, such as virtual private clouds and software-defined networking. I configure secure connectivity between on-premise and cloud resources and monitor performance using specialized tools. This approach ensures seamless integration and scalable network performance.

31

Suppose you connect a new switch to a network, and the entire network starts flapping. What could be the reason for this?

Reference answer

An issue that can cause the entire network to flap is a Layer 2 loop. It can be caused by improper cabling or Spanning Tree issues. Some symptoms of this issue are: - Flapping of MAC Address - High broadcast traffic - The network will be very slow - CPU spikes on switches To troubleshoot the issue, you can: - Check the status of STP - Find the links that can be reduced - Verify BPDU exchange - And disconnect suspected loop links The commands you need: "show spanning-tree" "show mac address-table"

32

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.

33

Explain the purpose of bandwidth throttling.

Reference answer

Bandwidth throttling limits data transfer rates to manage congestion and ensure fair usage.

34

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)

35

How Would You Go about Designing a WiFi 6/6E Network for Optimal Performance?

Reference answer

The primary aspects to consider while designing a WiFi 6/6E network include considering the environment, understanding the expected usage, and planning accordingly. Identifying the number of devices, the physical restrictions, and obtaining the right equipment are all things to consider. Moreover, understanding the need for speed, range, and capacity in different areas and planning multidirectional antennae coverage can optimise the wireless network's performance. In WiFi 6/6E network design, interference should always be kept in check for maximum performance.

36

What is a network typology?

Reference answer

Your answer should include a physical description of a company's computer network, including where the different systems are located and how they're connected.

37

What is Network Topology?

Reference answer

Network Topology refers to the layout of a computer network. It shows how devices and cables are spread out, as well as how they connect.

38

How do you handle network documentation and change management?

Reference answer

I handle network documentation by maintaining detailed records of network configurations, topologies, and device inventories. This includes using tools like Microsoft Visio for network diagrams and centralized repositories for documentation. For change management, I follow a structured process that includes submitting change requests, assessing risks, obtaining approvals, and scheduling changes during maintenance windows. I also document all changes and update relevant records to ensure accuracy and compliance.

39

Can you give an example of how you reacted to a potential security breach?

Reference answer

Network security is a vital part of keeping networks up and running when threatened by security issues. Use this question as an opportunity to talk about your experience implementing security measures needed to protect sensitive information or proprietary data while also preventing unauthorized access to your networks. Consider tailoring your response to specific rules and compliance requirements you may be familiar with based on your previous industry experience. Some examples include the Payment Card Industry Data Security Standard (PCI DSS) in the financial industry and the Health Insurance Portability and Accountability Act (HIPAA) in the health care industry.

40

What is the purpose of compression in network optimization?

Reference answer

Compression reduces data size, lowering bandwidth consumption and speeding up transfers.

41

How do you optimize wireless network performance in high-density environments?

Reference answer

Managers ask this to gauge your hands-on experience optimizing WLANs in challenging scenarios. They want to see that you can apply a multi-faceted approach. Successful candidates for a wireless network engineer job outline these essential strategies: Channel allocation and power management Client load balancing across access points Band steering implementation QoS policy configuration Interference mitigation techniques

42

List and describe the layers of the OSI reference model.

Reference answer

The OSI model has seven layers: physical, data link, network, transport, session, presentation, and application. Each layer handles specific aspects of network communication, from transmitting raw data bits to ensuring reliable data transfer. Understanding these layers is essential for diagnosing network issues.

43

Describe common software problems that lead to network defects. How do you resolve them?

Reference answer

Common software problems include misconfigured network settings, outdated or incompatible drivers, firewall or antivirus blocking legitimate traffic, and software bugs in network services. Resolutions involve verifying configuration files, updating drivers and software, adjusting firewall rules, and applying patches or reconfiguring services.

44

Why is WPA encryption preferred over WEP?

Reference answer

- Stronger Encryption: WPA provides better security and dynamic key changes, unlike WEP which uses static keys.

45

Explain the role of the DHCP relay agent.

Reference answer

A DHCP relay agent forwards DHCP requests from clients to a DHCP server on a different subnet.

46

What is OSI Model and why is it important?

Reference answer

The OSI (Open Systems Interconnection) Model is a conceptual framework that standardizes the functions of a telecommunication or computing system. It divides the network communication process into seven layers: - Physical Layer - Data Link Layer - Network Layer - Transport Layer - Session Layer - Presentation Layer - Application Layer The OSI model is important because it allows different network technologies to work together and enables troubleshooting by dividing complex network operations into manageable layers.

47

Define the functionality of the OSI session layer.

Reference answer

The OSI session layer provides the protocol and means for two devices on the network to communicate with each other by keeping a session. It is responsible for session establishment, management of session time information exchange, and tear-down process based on session termination.

48

Describe the 802.11 Association process

Reference answer

Explain the frame exchange between the endpoint/client and the Access Point before the client goes into ‘RUN' state and is authenticated and is able to pass traffic. Provide as much detail as possible. There can be spin off questions based on your response to this question. The answer is probe request, probe response, 802.11 open authentication request, auth response (success), client sends association/ reassociation request and AP responds to that with a association/reassociation response (success). After this depending on the security type of the WLAN/SSID, further frames are exchanged. in the below snippet of wireshark you can see the reassociation process followed by EAP/TLS handshake

49

What are the potential downsides of an infrastructure-based Wi-Fi network setup?

Reference answer

Potential downsides of an infrastructure-based Wi-Fi network setup include reliance on a central access point (single point of failure), potential performance bottlenecks, and higher complexity in configuration and maintenance.

50

Can you differentiate between the internet, intranet, and extranet?

Reference answer

The internet is a global network that connects thousands of computers. Information can be accessed and shared from any location that has access to the internet. An intranet is a network that is unique to a firm where data is accessed and shared among the computers within that network only. An extranet is a network where only specific members are allowed access. These may include vendors, customers, suppliers, and other officials who are associated with a company. The extranet handles the secure part of the website that is accessed through IDs and passwords.

51

Define the term Jitter?

Reference answer

Jitter is a “packet delay variance”. It can simply mean that jitter is considered a problem when different packets of data face different delays in a network and the data at the receiver application is time-sensitive, i.e. audio or video data. Jitter is measured in milliseconds(ms). It is defined as an interference in the normal order of sending data packets.

52

How do you Troubleshoot a Network Connectivity Issue?

Reference answer

In a connectivity issue, step by step structured troubleshooting approach is important. Here, firstly we check physical layer by controlling cable connection and link lights. Then, we check ip configuration of the related device. Then, we use ping tests by pinging localhost, default gateway, remote device. We can also use traceroute to see the path follow towards the destination device. DNS settings, Access List and Firewall rules are also other parts that we can check during a network connectivity issue. Follow-up Question: How do you verify if a device has a valid IP configuration? In different systems, we can check ip configurations with different commands: - In Windows: ipconfig - In Linux/Mac: ifconfig or ip addr With these commands we can verify IP address, Subnet mask, Default gateway, DNS server. These setting can be configured manually by static ip addressing or by the help of DHCP (Dynamic Host Configuration Protocol) with Dynamic IP Addressing. Here, we can also check if the device has an APIPA address (169.254.x.x) which indicates a DHCP failure.

53

Tell us about the biggest network you've engineered

Reference answer

Among the networks I've designed, implemented, and provided troubleshooting support on, the biggest one I worked on was with my former employer. This project involved interconnecting numerous locations across the country, providing seamless communication for their employees working both onsite and remotely around the world - the latter of which involved me setting up secure VPNs to enable safe access to the network from remote locations.

54

What is Bonjour?

Reference answer

Almost every Apple software comes with a tool called Bonjour that controls several of the company's automated discovery techniques. Bonjour is a cross between IPX and DNS. With little to no configuration needed, Bonjour uses mDNS (multicast DNS) to find broadcasting devices on the network. Due to potential security risks, many administrators will purposefully stop this service in a corporate setting. However, in a home setting, it can be up to the user to decide whether the risk is worth the convenience.

55

What is a reverse proxy?

Reference answer

Reverse Proxy Server: The job of a reverse proxy server is to listen to the request made by the client and redirect to the particular web server which is present on different servers. This is also used to restrict the access of the clients to the confidential data residing on particular servers. For more details please refer to what is proxy server article.

56

What's your experience with cloud networking or hybrid network architectures?

Reference answer

My experience is primarily with integrating AWS with on-premises infrastructure using VPN connections and Direct Connect. At one company, we were migrating some applications to AWS but needed them to seamlessly connect to our on-premises databases. We set up AWS Direct Connect, which gave us a dedicated network connection to AWS instead of routing traffic over the internet. On the AWS side, we configured VPCs with the right security groups and NACLs to control traffic flow. I also worked with site-to-site VPN as a backup connection in case the Direct Connect went down. The main learning curve was understanding the AWS networking model—they have their own equivalent of subnets called subnets, their own routing tables, and their own firewalling with security groups. It required thinking about network design in a slightly different way than on-premises, but the fundamentals of routing and segmentation still apply. I'm also starting to look at SD-WAN solutions that make hybrid architectures easier to manage.

57

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.

58

Explain the concept of a virtual switch.

Reference answer

A virtual switch connects virtual machines within a hypervisor, managing traffic between them.

59

Explain the differences between TCP and UDP and when you would use each.

Reference answer

TCP is a connection-oriented protocol that ensures reliable data transmission through error-checking and flow control, making it ideal for applications like web browsing and email. UDP, on the other hand, is a connectionless protocol that offers faster data transfer without error-checking, suitable for real-time applications like video streaming and online gaming.

60

What is SNMP?

Reference answer

SNMP stands for Simple Network Management Protocol. SNMP is a network protocol that allows data collection, organization, and transmission among network devices. SNMP is a prevalent tool in network management, utilized to configure various network devices such as hubs, servers, routers, printers, and switches. Critical components of SNMP are: - Management Information Base (MIB) - SNMP Manager - SNMP Agent - Managed device

61

Explain the difference between IOS and IOS XR.

Reference answer

IOS is used on traditional Cisco routers and switches, while IOS XR is a modular, highly available OS for service provider platforms.

62

How does DHCPv6 differ from DHCP in IPv4?

Reference answer

DHCPv6 assigns IPv6 addresses and options, but stateless autoconfiguration (SLAAC) is also common in IPv6.

63

What are the differences between OSPF and EIGRP, and when might you choose one over the other?

Reference answer

OSPF (Open Shortest Path First) is a link-state routing protocol that uses the Dijkstra algorithm to calculate the shortest path, while EIGRP (Enhanced Interior Gateway Routing Protocol) is a Cisco-proprietary protocol and employs a distance-vector approach using its metric components. OSPF has a broader industry acceptance since it's an open standard, whereas EIGRP is often chosen in Cisco-only environments for its rapid convergence times and ease of configuration. I'd lean towards OSPF in mixed-vendor environments to ensure interoperability, but might prefer EIGRP in a purely Cisco ecosystem for its enhanced features.

64

Describe your experience with network monitoring and what tools you've used.

Reference answer

Monitoring is essential because you can't fix problems you don't know about. I've worked with Nagios for alerting on device availability and basic metrics, and SolarWinds for more comprehensive traffic analysis and performance trending. At my last role, I set up custom thresholds in Nagios—for example, alerting if link utilization exceeded 80% for more than 15 minutes. That gave us early warning before we had congestion issues. I've also used Wireshark for packet-level troubleshooting when I need to see exactly what traffic is on the wire. The key is not monitoring everything—that's noise. I focus on monitoring what matters: link availability, utilization, and whether critical services are responding. I also keep dashboards visible so the team can quickly see network health without having to log into multiple systems.

65

How do you perform log analysis in network management?

Reference answer

Collect logs from devices, use tools like SIEM to correlate events, and identify anomalies.

66

What happens when you type a website address into your browser?

Reference answer

Your browser starts by looking up the website's real address. The name you type is not the actual location. DNS servers translate this name into a numerical IP address. Next, your browser creates a connection to that server. It utilizes the TCP protocol to establish a secure pathway for data transfer. This happens through a three-way handshake process. Your browser then requests the webpage. It sends an HTTP message requesting specific content from the server. This message includes details about what your browser can handle. The server handles this request, and it responds by transmitting the webpage files. The latter consists of HTML, CSS, JavaScript code, and graphics. The files flow back to your device via the internet. Your browser receives all of these components. It reads the code, applies the styling, and executes the scripts, displaying all on your screen as one whole web page. Understanding how browsers, DNS, TCP/IP, and servers communicate is an important part of networking fundamentals and is commonly covered in CCNA training. If you want to learn these concepts practically with real lab experience, you can explore the CCNA Course by PyNet Labs taught by CCIE-certified trainers.

67

How do you ensure network security in your designs?

Reference answer

I ensure network security by implementing multi-layered security measures, including firewalls, encryption, and strict access controls. Regular security audits and vulnerability assessments help me identify and mitigate potential threats proactively.

68

Can you define OSPF?

Reference answer

OSPF stands for Open Shortest Path First. This is a link-state routing protocol that is used for identifying the best path for transferring data packets. This protocol is useful as it makes use of the network bandwidth efficiently.

69

Have You Encountered Any Challenges Migrating a WiFi 5 Network to WiFi 6/6E, and How did You Handle Them?

Reference answer

Migrating from WiFi 5 to WiFi 6/6E could present challenges. Issues could spring from compatibility of hardware, need for upgraded devices, and adequate knowledge on the new technology. Nevertheless, these challenges can be tackled by carrying out a thorough assessment of the existing network infrastructure, understanding the technical requirements, and effectively communicating the expected benefits and changes to the stakeholders.

70

What is network automation, and why is it important?

Reference answer

Network automation reduces manual tasks, improves consistency, and accelerates deployments.

71

What is the purpose of an 802.1X authentication server in wireless networks?

Reference answer

An 802.1X authentication server (often a RADIUS server) provides centralized authentication for wireless clients. It verifies user credentials and grants access based on policies, enhancing network security and access control.

72

Describe the differences between IaaS, PaaS, and SaaS.

Reference answer

IaaS provides virtualized infrastructure, PaaS offers development platforms, and SaaS delivers software applications over the internet.

73

What Is the IP address for APIPA? When the DHCP server is unavailable, what IP address is sent to the computer?

Reference answer

The Windows client machine automatically assigns itself an IP address known as an APIPA when a DHCP server is unavailable, to communicate with other network computers.

74

What is the difference between a router and a switch?

Reference answer

A router is a network device that connects different networks and routes data packets between them based on IP addresses. It operates at the network layer (Layer 3) of the OSI model. A switch, on the other hand, is a network device that connects devices within the same network and forwards data based on MAC addresses. It operates at the data link layer (Layer 2) of the OSI model. Routers enable communication between different networks, while switches facilitate communication within the same network.

75

Describe the topics covered in the CCIE Routing and Switching certification.

Reference answer

CCIE covers advanced routing, switching, and network design with a rigorous lab exam.

76

Explain subnetting and CIDR notation with an example.

Reference answer

Subnetting means dividing a network into smaller parts. The subnet mask help in the division where it tells which part of an IP address is the network and which part is for hosts. CIDR notation is just a shorter way to represent this. For example, /24 means the first 24 bits are for the network, and the remaining 8 bits are for hosts. You can understand this with the help of an example: 192.168.1.0/24 Here: Total addresses = 256 Usable hosts = 254 But why not 256? It is because .0 is the network address and .255 broadcast address So actual usable IPs are: 192.168.1.1 to 192.168.1.254 Now if you split this /24 into two smaller networks: You increase the network bits - /25 192.168.1.0/25 192.168.1.128/25 This will give you two subnets: First: .0 to .127 Second: .128 to .255 Now when this happens, each subnet gets fewer hosts and the segmentation gets better. Now here are some quick info you need to keep in mind about subnetting - It reduces unnecessary broadcast traffic - improves security, i.e, isolation between networks - uses IP addresses more efficiently Some common CIDR values that you should remember are: /8 - 255.0.0.0 /16 - 255.255.0.0 /24 - 255.255.255.0 /32 - single host

77

What things should you consider when you work with several departments and large infrastructures?

Reference answer

One main issue with larger businesses is security. If the business hosts its own web host servers, you must understand how to protect the internal network from outside Internet traffic. Other issues include user management and desktop audits and inventory. You must be able to manage several desktops and servers at once.

78

What is a subnet mask?

Reference answer

A subnet mask is combined with an IP address to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits, and it determines the network and host portions.

79

Describe the purpose of SIP in VoIP.

Reference answer

SIP establishes, modifies, and terminates multimedia sessions like voice and video calls.

80

How do you troubleshoot poor call quality in a VoIP network?

Reference answer

Check for packet loss, jitter, latency, bandwidth issues, and codec mismatches using tools like Wireshark.

81

What is SSID, and why is it important in wireless networks?

Reference answer

SSID (Service Set Identifier) is the name assigned to a wireless network. It allows wireless devices to identify and connect to the correct network among multiple networks in the vicinity. The SSID is essential for network segmentation and user access.

82

Explain the concept of VLANs and their significance in modern network design.

Reference answer

VLANs allow networks to be segmented logically, grouping devices together based on functional requirements rather than their physical location. This ensures efficient utilization of resources and enhances security by isolating sensitive data. In modern network designs, VLANs aid in broadcast domain control, reducing unnecessary traffic. When implementing VLANs, I always emphasize the importance of proper documentation and consistent tagging to avoid misconfigurations. Properly implemented VLANs can dramatically streamline network management and bolster security measures.

83

Which frame has SSID ?

Reference answer

Beacon, Directed Probe request, Probe Response, Assoc Req, Re-association Req

84

Do you have any network engineering certifications?

Reference answer

This question tests your interest in and drive to stay current with changes in network engineering and whether you enjoy learning about new topics in the industry. You can discuss topics you learned from additional professional coursework youâ€™ve completed through different organizations or third-party platforms such as Coursera. Certifications are also a good way to boost your skills and show potential employers your dedication to understanding different aspects of network engineering. Some relevant certifications include: AWS Certified Advanced Networking - Specialty, CompTIA Network+, JNCIA-Junos, Microsoft Certified: Azure Network Engineer Associate.

85

What is Ad-Hoc networking in Wi-Fi and what are its specific applications?

Reference answer

Ad-Hoc networking in Wi-Fi allows direct device-to-device communication without an access point. Its specific applications include scenarios where devices need to communicate directly, such as in temporary network setups or peer-to-peer file sharing.

86

What is your preferred area of expertise within network engineering?

Reference answer

While I find every aspect of being a network engineer enjoyable, there is one particular area where my passion and expertise truly shine when I interact with clients and support with troubleshooting their server issues. I love the challenge of dealing with server and configuration problems and coming up with solutions that allow the client to get the most out of the network they're using.

87

Name the three means of user authentication.

Reference answer

There is biometrics (e.g. a thumbprint, iris scan), a token, or a password. There is also two-level authentication, which employs two of those methods.

88

Define the 4 different layers of the TCP/IP Reference Model

Reference answer

| Layer | Description | |---|---| | Link | Decides which links such as serial lines or classic Ethernet must be used to meet the needs of the connectionless internet layer. | | Internet | | | Transport | Its functionality is almost the same as the OSI transport layer. It enables peer entities on the network to carry on a conversation. | | Application | It contains all the higher-level protocols. |

89

What is the minimum size of the icmpV4 packet what is the maximum size of the icmpv4 packet?

Reference answer

- Minimum size ICMPv4 packet = 28 bytes - Maximum size ICMPv4 packet = 2068 bytes

90

How does caching improve network performance?

Reference answer

Caching stores frequently accessed data locally, reducing bandwidth usage and latency.

91

What are the requirements for using a Wi-Fi network and the necessity of an account?

Reference answer

Requirements for using a Wi-Fi network include a device with a Wi-Fi adapter and proximity to an access point. An account may be necessary for secured or paid networks, but open networks may not require one.

92

Can you state the differences between a switch, router, and a hub?

Reference answer

A switch is used for forwarding the data packets in a network. It facilitates error checking for the data packets and send error-free packets to the destined ports properly. A router is a networking device that transfers data packets after analyzing their contents. The correct destination, correctness and IP address of the data packets are checked by the router. They make use of a routing table for finding out the best path for transmission. A hub is a connection point for networking devices. Different segments of a LAN are connected using a LAN. It also has several ports for communication. If a packet arrives at a hub port, it is copied to the other ports so that it is visible to the other segments of the LAN. But as they are unable to filter data, it sends the data packets to all the connected devices.

93

Tell me something about VPN (Virtual Private Network)

Reference answer

VPN or the Virtual Private Network is a private WAN (Wide Area Network) built on the internet. It allows the creation of a secured tunnel (protected network) between different networks using the internet (public network). By using the VPN, a client can connect to the organization's network remotely. The below diagram shows an organizational WAN network over Australia created using VPN:

94

How do you configure and manage VPNs?

Reference answer

I configure and manage VPNs by setting up secure tunnels between remote users or sites and the main network. This involves configuring VPN gateways, defining encryption protocols (such as IPsec or SSL), and setting up authentication methods (such as certificates or two-factor authentication). I also manage VPN policies and monitor connections to ensure secure and reliable remote access.

95

Describe the differences between IPv4 and IPv6.

Reference answer

IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses, offering larger address space and improved features like autoconfiguration.

96

What is DHCP and how does it function?

Reference answer

DHCP (Dynamic Host Configuration Protocol) is a protocol that automatically assigns IP addresses to network devices. When a device joins the network, the DHCP server assigns it an IP address, gateway, and other network parameters, simplifying network management.

97

What are the layers of the OSI reference model?

Reference answer

The OSI reference model has seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

98

How do you troubleshoot network congestion issues?

Reference answer

Identify bottlenecks with monitoring tools, analyze traffic patterns, and adjust QoS or upgrade links.

99

What is the difference between unicast, multicast, and broadcast traffic?

Reference answer

Unicast: It involves a one-to-one transmission. One sender sends the data to a single and specific receiver. It can be described as direct communication between two devices. Multicast: A one-to-many transmission is multicasting. Data is sent by one sender to multiple interested receivers. Broadcast: It is a one-to-all transmission. One sender sends data to every device on the entire local network. All devices receive the data, whether they need it or not.

100

What is a routing table?

Reference answer

A routing table is a data structure stored in a router that contains routes to network destinations, used to determine the best path for packet forwarding.

101

How do you handle configuration drift in network automation?

Reference answer

Use version control and automated compliance checks to detect and correct deviations from desired state.

102

Explain the concept of SSID.

Reference answer

An SSID (Service Set Identifier) is the name of a wireless network, used by clients to identify and connect to a specific Wi-Fi network.

103

What is the TCP IP model in networking?

Reference answer

The TCP IP (Transmission Control Protocol and Internet Protocol) model is a more precise representation of the OSI model. The current architecture of the internet is based on the TCP IP model. It was developed by the Department of Defence's Project Research Agency as a part of their project for communication within systems and remote machines. It has 4 layers that have protocols required for communication between devices of a network. They are as follows: - Application Layer (Process layer) - Transport Layer (Host-to-Host layer) - Internet Layer - Link Layer (Network Access)

104

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

Reference answer

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

105

How do you prioritize tasks when managing multiple network projects?

Reference answer

I prioritize tasks by assessing their urgency and impact on business operations, ensuring critical issues are addressed first. I also allocate resources based on project complexity and team expertise, regularly reviewing and adjusting priorities as needed.

106

Explain the role of a router in a network.

Reference answer

A router forwards packets between networks based on IP addresses, enabling inter-network communication.

107

What do you understand by Sneakernet?

Reference answer

It is the earliest form of networking where data is physically transferred through removable media.

108

What is the difference between static and dynamic routing?

Reference answer

Static routing is manual; dynamic routing uses automatic updates.

109

Who are the providers and what are the assets available for wireless?

Reference answer

Some of the providers for wireless are as follows:- a) Wireless Internet- Nationwide Coverage Unlimited b) Faster Internet on Mobile c) New 3G BlackBerry d) Aircel Pocket Internet e) Reliance 3G Online Offer f) Cisco Managed Switches Brand assets are available here for wireless, brand assets can also be applied to m-branding. In particular, three of the assets can be targeted directly for improvement with the m-branding methods that are available today. These are brand awareness, brand associations and brand loyalty.

110

What network monitoring tools are you familiar with?

Reference answer

I'm familiar with tools like SolarWinds, PRTG, and Nagios. Key features include network monitoring, performance analysis, traffic flow analysis, and alerting systems.

111

Define VLAN and its benefits.

Reference answer

A VLAN (Virtual Local Area Network) logically segments a physical network into separate broadcast domains. Benefits include improved security, reduced broadcast traffic, and simplified network management.

112

Your OSPF area 0 is stable, but a new area is not learning routes. What could be wrong?

Reference answer

Check area type (stub, NSSA) mismatch, authentication mismatch, or missing area x command. Also confirm ABR has route summarization configured properly.

113

How does serverless computing impact network architecture?

Reference answer

Serverless computing shifts focus to event-driven functions, requiring dynamic, scalable network connections.

114

Suppose a company wants network redundancy between 2 core switches. What solution would you recommend?

Reference answer

The best thing to recommend in such a case is: - EtherChannel/LACP for link redundancy - HSRP or VRRP for gateway redundancy - Dynamic routing protocols for failover - Spanning Tree optimization Here are some benefits of it: - High availability - Downtime will be reduced - Load balancing - Automatic failover

115

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.

116

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.

117

What is the protocol and port no of DNS?

Reference answer

Protocol - TCP/UDP Port number- 53

118

How do switches work in a network?

Reference answer

Switches can connect two or more network segments. These are intelligent network devices that store information in their routing tables, like paths, hops, and bottlenecks. With this information, they can determine the best path for data to move. Switches work at the OSI Network Layer.

119

How would you connect two computers for file sharing without using a hub or router?

Reference answer

The candidate can explain using an Ethernet crossover cable to directly connect the two computers, then configure both systems with static IP addresses in the same subnet and enable file sharing services such as SMB or FTP.

120

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.

121

What is STP (Spanning Tree Protocol)?

Reference answer

STP prevents network loops in Ethernet networks by creating a loop-free logical topology, blocking redundant links to avoid broadcast storms.

122

Describe a situation where you had to work with a team to resolve a complex network issue.

Reference answer

Our team faced a critical network outage affecting multiple departments. I coordinated with colleagues to systematically isolate the issue, ultimately identifying a misconfigured router. Together, we resolved the problem within hours, restoring full network functionality.

123

What is a hub-to-hub connection?

Reference answer

A hub-to-hub connection refers to a direct connection between two computers on a network. A hub-to-hub connection does not need any other network devices besides connecting a cable to the NIC cards of the two computers.

124

What tools do you rely on for network monitoring and management?

Reference answer

I utilize tools such as SolarWinds, Nagios, and Wireshark to monitor network performance and troubleshoot issues. These tools provide real-time insights into traffic patterns, device statuses, and potential vulnerabilities. My familiarity with these platforms enables proactive maintenance and rapid response to incidents.

125

Describe the role of a proxy server in network security.

Reference answer

A proxy server acts as an intermediary between clients and servers, filtering requests, caching content, and hiding internal IP addresses for security.

126

What is the role of VXLAN in network virtualization?

Reference answer

VXLAN extends Layer 2 networks over Layer 3 using encapsulation, enabling large-scale virtualization.

127

What is the difference between WiFi and Bluetooth?

Reference answer

WiFi falls under the WLAN category, while Bluetooth falls under the WPAN category. WLAN specifications are published under IEEE 802.11, and Bluetooth under IEEE 802.15 standards. Bluetooth is the standard for wireless personal area networks or WPANs. It allows high-speed transmission of data over very short distances.

128

How Does the Introduction of the 6 GHz Band with Wi-Fi 6E Help Improve Network Performance?

Reference answer

WiFi 6E's main advantage is its expansion into the 6GHz band, adding up to 1200MHz of additional spectrum for WiFi use. This helps in accommodating more devices and ensuring more efficient data transmission. Furthermore, because this band is less congested compared to 2.4GHz and 5GHz, networks using 6GHz can achieve higher data rates and reduce latency, thus enhancing the network's overall performance.

129

Describe the purpose of the HTTP and HTTPS protocols.

Reference answer

HTTP (Hypertext Transfer Protocol) transfers web data, while HTTPS adds encryption via SSL/TLS for secure communication.

130

Describe your experience with virtual private networks (VPNs).

Reference answer

I have extensive experience deploying and managing VPNs to provide secure remote access for employees. I configure various VPN protocols, such as IPsec and SSL, ensuring encrypted connections and data integrity. My work includes troubleshooting VPN performance issues and integrating VPN solutions with existing network infrastructures.

131

What is the difference between a forward proxy and a reverse proxy?

Reference answer

A forward proxy and a reverse proxy both work as a middleman in a network, but their differences lie in who they protect and where they are placed in a network. | Forward Proxy | Reverse Proxy | | It works for users/clients. | It mainly works for servers. | | It sits in front of users. | It sits in front of the servers. | | It is used to hide the client's identity. | It is used to hide the server's identity. | | Used inside organizations | Used in data centers and websites | | It primarily controls the user's internet access. | It primarily controls incoming user requests. |

132

What's your experience with WLAN design, and describe your most successful outcome with WLAN design?

Reference answer

The candidate should discuss their WLAN design projects, including site surveys, capacity planning, and a specific successful deployment with measurable results.

133

How would you troubleshoot one way audio issue

Reference answer

Typically one way audio issues stem from power mismatch between the AP and the VoWiFi device. The VoWiFI device has limited transmit power compared to the AP which can cause one way audio issues. The VoWiFi device can hear the AP communication even at relatively far off distances but at cell edge or beyond if the VoWiFi transmits data back, the AP sometimes cannot interpret the data leading to one way audio. This is the simplest form of one way audio issue. You need to determine if the communication is between 2 VoWiFi devices or one VoWiFi and one wired phone. There could be configurations that may block peer to peer communication which may potentially lead to one way audio or no audio between two VoWiFi devices. The way to troubleshoot such issue is normally double check the configurations are ok and adhere voice of wifi best practices and then delve into debugs + over the air captures for further isolating the problem.

134

Can you define the OSI model?

Reference answer

The OSI (Open System Interconnection) is a reference model that has the necessary protocols and standards for communicating over a network. The model was made by the International Organization for Standardization (ISO) in 1984. It consists of seven layers, where each layer has a different function. These layers are Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer, and Application Layer.

135

How do you troubleshoot network issues?

Reference answer

Troubleshooting is a crucial part of being a Network Engineer. Employers want to know your process for diagnosing and solving problems as they occur. For example, you could discuss using a top-down approach that begins with the ping utility, then moves to traceroute if the issue isn't solved. Other problem-solving methods include: - Investigating the IP configuration - Using NSlookup to locate a DNS issue - Using the Netstat utility to diagnose further - Checking and double-checking utilities like Route, PathPing, Speedtest, and the IP Network Calculator

136

Explain in as much detail as possible when you try and ping a server on the internet

Reference answer

Assuming the ping involves a packet being sent over an Ethernet or WiFi network, ARP is used to find the Ethernet hardware address of the device that receives the outbound packet. Typically this will be the router for the LAN the machine originating the ping is on. The typical process is: - You enter a command to ping a destination. - DNS is used to determine the IP address (if needed). - The routing table is consulted to find the next hop towards that destination. - ARP is used to find the hardware address of the next hop. - The IP packet is sent to the next hop, encapsulated in an Ethernet or WiFi frame

137

What are rights in a network context?

Reference answer

Rights refer to the authorized permission to perform specific actions on the network. Each user on the network can be granted individual rights, depending on what needs to be considered by that user.

138

How do you ensure compliance with network security policies and regulations?

Reference answer

I ensure compliance with network security policies and regulations by implementing and enforcing security controls, conducting regular audits and vulnerability assessments, and staying updated with relevant laws and standards. I also provide training for users and staff on security best practices and monitor compliance through continuous monitoring and reporting.

139

Talk about how youâ€™ve used network protocols in your professional life.

Reference answer

As a network engineer, youâ€™ll need specific skills in your daily toolbox that are foundational to the field. You want to be well-versed in protocols such as TCP/IP, OSI, BGP, and others, so review how youâ€™ve interacted with these network fundamentals in your professional life. Also, come up with examples of this work that can help you stand out from other applicants. Discuss projects in which you were responsible for fundamentals and try to bring up other technical skills you utilized on these projects to illustrate how your skill set fits your everyday work environment.

140

What is the 802.11b standard?

Reference answer

Introduced in 1999, 802.11b operates in the 2.4 GHz frequency band and offers a maximum data rate of 11 Mbps. It uses direct-sequence spread spectrum (DSSS) technology. It has a longer range than 802.11a, but its lower frequency makes it more prone to interference from other devices.

141

What factors should be considered when designing a solid disaster recovery plan?

Reference answer

A number of factors need to be cautiously considered when designing a solid disaster recovery plan. Recovery Point Objective (RPO) sets up the maximum allowable data loss, so although Recovery Time Objective (RTO) the maximum allowable downtime. Duplication, which includes hardware, links, and geographically diverse locations, is crucial. It is essential to set up and test thorough data backup and restoration protocols on a regular basis. Minimize manual intervention by implementing automated failover mechanisms. To make sure the plan is effective, it needs to be well documented and tested frequently. Solutions for disaster recovery that are cloud-based offer greater scalability and flexibility.

142

Explain the concept of latency and how to minimize it.

Reference answer

Latency is delay in data transmission; minimize it by optimizing routing, using faster links, and reducing hops.

143

Can you explain how VLANs work and why they are used?

Reference answer

VLANs (Virtual Local Area Networks) work by segmenting a physical network into multiple logical networks. Each VLAN has its own broadcast domain, which helps reduce network congestion and improve security by isolating different types of traffic. VLANs are used to separate different departments or types of traffic within an organization, enhance network performance, and provide better control over network resources.

144

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

145

Explain the function of the spanning-tree portfast command.

Reference answer

Portfast bypasses the STP listening/learning states on access ports, speeding up device connectivity.

146

What does WAN stand for?

Reference answer

WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks located in different regions and countries.

147

What is the significance of the IP address 127.0.0.1?

Reference answer

127.0.0.1 is the loopback address, used to test network software on the local machine without sending packets over the network.

148

Explain a scenario where you had to implement a security measure to protect the network from a specific threat.

Reference answer

I deployed ACLs to block malicious IPs and configured IPS signatures to detect similar attacks.

149

What is the concept of piggybacking with Wi-Fi networks and its implications?

Reference answer

Piggybacking with Wi-Fi networks refers to unauthorized users accessing a wireless network without permission. Its implications include security risks, bandwidth theft, and potential legal issues.

150

What is the significance of Git in network automation workflows?

Reference answer

Git tracks changes to automation scripts and configurations, enabling collaboration and rollback.

151

Major differences between Cisco 2500 Series and 5500 Wireless Controllers?

Reference answer

- Cisco 2500 vs 5500: 5500 supports more APs and clients, offers higher throughput, and advanced features compared to 2500.

152

What do understand by domain and workgroup?

Reference answer

Domain is a group of computers in a network, which are connected. The members of a domain consist of users, workstations and database servers. Devices within the same domain are administered using the same protocols and rules. When an active directory is installed, a domain is created. Domains can be used for administering computers centrally, which is not possible in a workgroup. A workgroup is a set of connected computers that share resources. Here, all the computers are peers and they do not have control over one another. All peers must be on the same LAN and subnet.

153

How do you ensure compliance with industry regulations and best practices in network management?

Reference answer

I implement policies like encryption, access controls, and regular audits aligned with standards like PCI-DSS.

154

How does SSL/TLS ensure secure communication?

Reference answer

SSL/TLS uses encryption, authentication, and integrity checks via certificates and handshake protocols to secure data transmission over networks.

155

What is DHCP, and why is it employed? What are superscopes and scopes?

Reference answer

- Dynamic Host Configuration Protocol (DHCP): In a network setting, DHCP distributes IP addresses to many PCs, simplifying IP address management. - Scope: A scope is a collection of IP addresses a client can use to communicate with other network PCs. Gateway IP, Subnet masks, DNS server IP, and exclusion range are included in IP addresses. - Superscope: Superscopres are a combination of two or more scopes.

156

Which technique is used in byte-oriented protocols?

Reference answer

Byte stuffing is used in byte-oriented protocols. A special byte is added to the data section of the frame when there is a character with the same pattern as the flag.

157

What is ESS?

Reference answer

ESS (Extended Service Set): Created by connecting multiple BSSs via a distribution system, allowing larger coverage and seamless client roaming.

158

How do you handle network latency and optimize for low-latency communication in a globally distributed cloud environment?

Reference answer

To handle network latency in a global cloud environment, I leverage Content Delivery Networks (CDNs). I optimize routing to improve efficiency and prevent network outage. I also use edge locations strategically to reduce delays. Caching mechanisms are implemented to speed up data remote access. I use regional deployments wherever possible. This helps bring services closer to users. Additionally, I optimize application code for network efficiency. These measures cut latency and ensure optimal performance for users worldwide.

159

What is a node?

Reference answer

A 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.

160

How do you stay updated with the latest advancements in wireless technology and ensure your team benefits from them?

Reference answer

I regularly read industry publications like IEEE Wireless Communications and attend conferences like Mobile World Congress. I also encourage my team to participate in webinars and training sessions. For instance, after attending a workshop on 5G technology, we integrated new techniques into our project, leading to a 25% improvement in data transmission rates. Creating a culture of ongoing learning is vital for our team's success.

161

Explain the primary functions of a router.

Reference answer

A router directs data packets between networks by selecting optimal paths for transmission. It facilitates communication between different subnets and ensures security by filtering traffic. In my experience, routers are key to managing network efficiency and connectivity.

162

What is your experience with implementing an SSO feature?

Reference answer

The candidate should describe their hands-on experience with Single Sign-On (SSO) implementations, including protocols like RADIUS or SAML.

163

What is the difference between HSPA and HSPA+?

Reference answer

HSPA (High-Speed Packet Access): An evolution of 3G technologies, offering faster data rates compared to basic 3G. HSPA+: An enhanced version of HSPA that offers higher data rates, lower latency, and improved spectral efficiency, often referred to as "3.5G."

164

How do you handle network capacity planning?

Reference answer

I analyze current usage trends, forecast future growth, and consider factors like new applications or services. I use this information to plan for upgrades or expansions to ensure the network can handle future demands without performance degradation.

165

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.

166

How do you approach troubleshooting a network issue?

Reference answer

When troubleshooting a network issue, I start by systematically isolating the problem using tools like Wireshark and PRTG. I then analyze the data to identify the root cause and implement a solution, ensuring to document each step for future reference.

167

What are the Advantages of Fiber Optics?

Reference answer

The advantages of Fiber Optics are mentioned below: - Bandwidth is above copper cables. - Less power loss and allows data transmission for extended distances. - The optical cable is resistant to electromagnetic interference. - Fiber cable is sized 4.5 times which is best than copper wires. - As the cable is lighter, and thinner, in order that they use less area as compared to copper wires. - Installation is extremely easy thanks to less weight. - Optical fiber cable is extremely hard to tap because they don't produce electromagnetic energy. These optical fiber cables are very secure for transmitting data. - This cable opposes most acidic elements that hit copper wires also are flexible in nature. - Optical fiber cables are often made cheaper than equivalent lengths of copper wire. - Light has the fastest speed within the universe, such a lot faster signals. - Fiber optic cables allow much more cable than copper twisted-pair cables. - Fiber optic cables have how more bandwidth than copper twisted-pair cables.

168

What is Border Gateway Protocol (BGP) and its purpose?

Reference answer

Border Gateway Protocol (BGP) is the essential routing protocol used between different Autonomous Systems (AS) on the internet. An AS is a network under a single administrative domain, like an ISP or a large organization. BGP's primary purpose is to exchange routing information between these ASes, enabling internet-wide connectivity. Unlike interior gateway protocols, BGP is a path-vector protocol, meaning it considers the entire path of ASes when choosing the best route to a destination. This helps prevent routing loops and allows for policy-based routing between ASes.

169

What is the waiting time for each channel for Active and Passive scan?

Reference answer

Maximum and Minimum waiting time for each channel for scanning are defined by “MaxChannelTime[TU]” and “MinChannelTime[TU]” parameter respectively. Waiting time may vary from vendor to vendor implementation. For Active Scanning: MinChannelTime = 0.67 ms [MinChannelTime >= DIF S + CW ∗ aSlotT ime = 50 µsec + 31 * 20 µsec = 670 µsec = 0.67ms] MaxChannelTime = 15 ms For Passive Scanning : MinChannelTime will be > 100TU [As default beacon interval is 100TU for APs]

170

What is roaming in a wireless network, and how does it work?

Reference answer

Roaming allows a wireless device to move between different access points within the same network without losing connectivity. The wireless controller or access points manage the handoff process to ensure seamless connection and maintain network performance.

171

What is a link?

Reference answer

The connectivity between two devices is something we refer to as a link. It comprises cables and protocols used so two devices can talk to one another.

172

How do you configure IPv6 on a router interface?

Reference answer

Use commands like ipv6 enable and ipv6 address to assign an IPv6 address to the interface.

173

How would you troubleshoot low throughput issue on the wifi network

Reference answer

There is no real ‘correct' answer for such open ended questions. The interviewer is trying to access your analytical thinking and troubleshooting skills. If the interview is for a customer rep or test engineer, this question would be very important. Throughput issues can steam from variety of root causes. It is important to ask a few questions and understand what is the problem symptom before you get started. You should look at the data rate at which the client is connecting (802.11n, ac etc), what MCS rate and the clients capability, SNR, RSSI of the client to start off with. A handy tool is WLC / AP debugs logs in conjunction with Over-the-air 802.11 sniffer captures. You can follow the traffic pattern (you won't be able to decode the actual qos data on most occasions) to try and get a sense of any RF issues (if you see too many Retries or rate downshift). On odd occasion if there is a bug you may land up with incorrect sequencing of the data frames, qos mis configs and potential A-MPDU issues. Next step once you are past the Layer 1 and 2 of the OSI model is to start exploring the layer 3 traffic (decapsulated, preferably at the VLAN level or default gateway). Check for TCP windowing issues or retransmit etc. The problem could be between specific hosts/ servers etc.

174

What is the significance of the 169.254.x.x IP address range?

Reference answer

169.254.x.x is an APIPA (Automatic Private IP Addressing) range used when a device fails to obtain an IP from DHCP, indicating a configuration issue.

175

Can a routing table in the datagram network have two entries with the same destination address?

Reference answer

No.routing tables in the datagram network have two entries with the same destination address, not possible because the destination address or receiver address is unique in the datagram network.

176

What is the OSI model? Explain each layer.

Reference answer

The OSI Model is a conceptual framework with 7 layers: 1️⃣ Physical – Transmission of raw bits 2️⃣ Data Link – Error-free frame transfer 3️⃣ Network – Routing using IP 4️⃣ Transport – Reliable/unreliable data delivery 5️⃣ Session – Connection management 6️⃣ Presentation – Data formatting & encryption 7️⃣ Application – Services like email, FTP, and web access.

177

What is the difference between CAPWAP and LWAPP?

Reference answer

CAPWAP vs LWAPP: CAPWAP supports both IPv4 and IPv6, provides better security, and uses DTLS, whereas LWAPP only supports IPv4 and is less secure.

178

What is a server farm?

Reference answer

A server farm is a set of many servers interconnected together and housed within the same physical facility. A server farm provides the combined computing power of many servers by simultaneously executing one or more applications or services. A server farm is generally a part of an enterprise data center or a component of a supercomputer. A server farm is also known as a server cluster or computer ranch.

179

Explain the concept of a virtual private cloud (VPC).

Reference answer

A VPC is an isolated, private network within a public cloud, offering control over IP addressing and security.

180

What is the Shannon-Hartley theorem?

Reference answer

The Shannon-Hartley theorem defines the maximum data rate (capacity) of a communication channel based on its bandwidth and SNR. It provides a theoretical limit on how much information can be transmitted error-free over a given channel.

181

What are the recommended channel settings for optimizing Wi-Fi communication?

Reference answer

Recommended channel settings for optimizing Wi-Fi communication include using non-overlapping channels (e.g., channels 1, 6, and 11 for 2.4 GHz) and selecting less congested channels to minimize interference.

182

How do you secure a wireless network?

Reference answer

Key points for securing a wireless network are as follows:- a) Verify that your PC's software firewall is turned on, and that Window's file-sharing feature is off; it's off by default in Window's XP with Service Pack 2. b) Never send bank passwords, credit card numbers, confidential e-mail, or other sensitive data unless you're sure you're on secure site: Look for the lock icon in the bottom-right corner of your browser, as well as a URL in the address bar that begins with https. Such sites build in their own encryption. c) Always turn your Wi-Fi radio off when you're not at a hotspot: Hackers can use it to create peer-to-peer Wi-Fi connections with your computer and access it directly. d) For better security, consider signing up for a paid subscription to a hotspot network such as Boingo or T-Mobile. Both companies provide connection software that encrypts your sessions automatically. By attaining these key points you can secure wireless network up to an extent.

183

Can you discuss what a network topology is?

Reference answer

A network topology refers to the arrangement of different elements (nodes, links, etc.) within a computer network. It visually represents how devices connect and communicate. I've worked with star, ring, mesh, and hybrid topologies, selecting each based on scalability and redundancy needs.

184

Who are the major providers of Wi-Fi services?

Reference answer

Major providers of Wi-Fi services include notable tech companies and mobile operators, such as those offering public hotspots and home internet services.

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 is the importance of APIPA in networking?

Reference answer

APIPA stands for Automatic Private IP Addressing. This is an important feature of Windows systems that allow the device to assign an IP address to itself when there is no DHCP. This IP address has a range of 169.254.0.1 through 169.254.255.254. Any client system can use this APIPA address until the DHCP server is available. This facility is commonly used for small organizations having about 25 clients.

187

How do you stay updated on the latest networking technologies?

Reference answer

I regularly read industry publications, attend webinars and conferences, participate in online forums, and pursue relevant certifications. I also experiment with new technologies in lab environments to gain hands-on experience.

188

What is traceroute (tracert) and how does it help?

Reference answer

Traceroute checks the path to a destination.

189

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.

190

Can IP Multicast be load-balanced?

Reference answer

No, The IP multicast multipath command load splits the traffic and does not load balance the traffic. Traffic from a source will use only one path, even if the traffic far outweighs traffic from other sources.

191

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.

192

Describe a time you ran into a problem when you were in the field you didn't know how to solve right away, and how did you address it?

Reference answer

The candidate should provide an example of a challenging field issue, explain their problem-solving approach, and detail how they eventually resolved it.

193

What are profiles in networking?

Reference answer

Profiles are the configuration settings created for each user. A profile could be created that places a user in a group, for example.

194

Can you give an example of when you had to fix a network problem at a previous job?

Reference answer

Troubleshooting can be an important part of your daily workload as a network engineer when finding and diagnosing equipment that might not work properly. You may have to track down hardware issues, software bugs, and even security problems quickly and professionally. So, itâ€™s important that you can explain your process for identifying issues and resolving them efficiently and accurately.

195

How would you go about troubleshooting an issue with a network?

Reference answer

When tasked with troubleshooting a network issue, I follow a systematic approach that begins with identifying the problem at hand and formulating a working hypothesis as to why the problem has occurred. I'll then validate my theory by executing relevant procedures or implementing specific codes. Throughout the troubleshooting process, I carefully look into the outcomes and make necessary adjustments until I successfully pinpoint both the root of the problem and the appropriate solution. This methodical approach allows me to tackle network challenges effectively and efficiently with minimal downtime for the end user.

196

What is a link?

Reference answer

A connection between two or more devices is called a link. A link defines different protocols that help a device to connect with another device within a network.

197

What are the authentication mechanisms supported by Cisco Access Points?

Reference answer

Mechanisms Include: WEP, WPA, WPA2, EAP, MAC authentication.

198

What Is WiFi 6 And How Does It Differ from Previous Versions?

Reference answer

WiFi 6, otherwise known as 802.11ax, is the newest wireless standard from the IEEE. It promises maximum speeds up to nearly three times faster than WiFi 5 and more remarkable performance in crowded areas. WiFi 6 outdoes its predecessors by accommodating more devices simultaneously and improving overall bandwidth usage with its MU-MIMO and OFDMA technology, resulting in a more stable and reliable connection.

199

What are the different types of VPN?

Reference answer

Few types of VPN are: - Access VPN: Access VPN is used to provide connectivity to remote mobile users and telecommuters. It serves as an alternative to dial-up connections or ISDN (Integrated Services Digital Network) connections. It is a low-cost solution and provides a wide range of connectivity. - Site-to-Site VPN: A Site-to-Site or Router-to-Router VPN is commonly used in large companies having branches in different locations to connect the network of one office to another in different locations. There are 2 sub-categories as mentioned below: - Intranet VPN: Intranet VPN is useful for connecting remote offices in different geographical locations using shared infrastructure (internet connectivity and servers) with the same accessibility policies as a private WAN (wide area network). - Extranet VPN: Extranet VPN uses shared infrastructure over an intranet, suppliers, customers, partners, and other entities and connects them using dedicated connections.

200

What is a fault tolerance system?

Reference answer

A fault tolerance system ensures continuous data availability by eliminating a single point of failure.

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Basic to Advanced Wi-Fi Engineer Interview Questions | SPOTO

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Basic to Advanced Wi-Fi Engineer Interview Questions | SPOTO

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