WLAN Designer Mock Interview Questions for Success

1

What are the key principles you consider when designing a new network?

Reference answer

In designing a new network, I prioritize scalability, reliability, security, and performance. Scalability ensures that the network can grow with the organization, while reliability minimizes downtime. Security is crucial to protect sensitive data, and performance is vital for user satisfaction. For instance, in a class project, I designed a network for a small business, implementing VLANs for security and using load balancers to enhance performance. This approach reinforced my understanding of how to balance these principles effectively.

2

Explain the difference between TCP and UDP in more detail.

Reference answer

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both internet protocols used for sending data packets over a network. TCP is connection-oriented, meaning it establishes a connection before sending data, ensures reliable data transfer with error checking and retransmission, and guarantees ordered delivery of packets. UDP, on the other hand, is connectionless, sending data packets without establishing a connection. It's faster than TCP but doesn't guarantee delivery, order, or error checking. Choose TCP when reliability is crucial, such as for web browsing, email, and file transfer. Choose UDP when speed is more important than reliability, such as for streaming video, online gaming, and DNS lookups where occasional packet loss is tolerable. Code example: using socket.SOCK_STREAM creates a TCP socket, while socket.SOCK_DGRAM creates a UDP socket.

3

What is the role of an antenna in wireless communication?

Reference answer

An antenna is used to convert electrical signals into electromagnetic waves for transmission and vice versa for reception. The design, type, and orientation of an antenna significantly affect the performance of a wireless communication system.

4

What is a VPN and how does it enhance privacy?

Reference answer

A VPN, or Virtual Private Network, amplifies your internet privacy by creating a private network from a public internet connection. When you send data over the internet, typically that data can go through several different servers before it reaches its destination, which can expose it to interception or monitoring. With a VPN, however, your data is encrypted and sent to a specific VPN server before it's sent to its final destination. The VPN server acts as a sort of middleman. When you send a request, that request goes to the VPN server, which then sends the request on your behalf. The response also comes back to the VPN server first and then goes to you. This means to anyone monitoring network traffic, it looks like all your data is just going between you and the VPN server. This process enhances your privacy online because it masks your IP address, making it more difficult for others to track your online activities. Additionally, since the VPN server can be located anywhere in the world, you can appear to be browsing from that location, which can bypass regional restrictions on content. As a result, VPNs are crucial for preserving privacy, especially when using public Wi-Fi networks.

5

Do you have experience with Cisco Prime, WLCs, and other Cisco products?

Reference answer

This question evaluates the candidate's hands-on experience with specific Cisco wireless products, such as Prime Infrastructure, Wireless LAN Controllers (WLCs), and related networking equipment.

6

Describe your experience with network monitoring systems and how you use them to proactively identify and resolve issues.

Reference answer

I have experience implementing and managing network monitoring systems using tools like Nagios, Zabbix, and Prometheus. My approach involves setting up comprehensive monitoring for key network devices (routers, switches, firewalls) and services (DNS, DHCP, web servers). This includes tracking metrics like CPU utilization, memory usage, bandwidth utilization, latency, and packet loss. Alert thresholds are configured based on established baselines to trigger notifications when anomalies occur. To proactively identify and resolve issues, I use the monitoring system to visualize trends and identify potential bottlenecks. For example, if bandwidth utilization on a specific link consistently exceeds a certain threshold during peak hours, I can investigate capacity upgrades or traffic shaping strategies. Similarly, unusual latency spikes might indicate a routing problem or a network device failure. I also configure automated remediation tasks where possible, such as restarting a service or running diagnostic scripts when specific alerts are triggered. The data collected is used to generate reports, providing insights into network performance and informing future network optimization efforts.

7

What is a firewall and how does it work in networking?

Reference answer

A firewall acts like a security guard between networks, deciding which traffic to allow through and which to block. It's essentially a barrier designed to prevent unauthorized access to or from a private network, usually your personal or organizational network. Firewalls can be hardware, software, or a combination of both. They use predefined rules to filter traffic based on criteria like IP addresses, domain names, protocols, programs, or ports. For example, if an incoming packet's IP is from a known malicious source, it will be blocked. Apart from blocking unwanted traffic, firewalls also offer services like logging and auditing. This can be helpful in understanding patterns, detecting inconsistencies, and tracking suspicious activity. In essence, the role of a firewall in networking is to maintain a secure environment by enforcing access policies and providing a line of defense against different types of attacks.

8

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.

9

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

Reference answer

The CIDR notation /24 represents a network with a subnet mask of 255.255.255.0.

10

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.

11

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.

12

A Customer has 2 Internet Links from different providers and using Public IP of 1st Provider to Host the website. On a day, the 1st Provider Link goes down and customer is not able to access the Web server from the Internet. What could be the reason?

Reference answer

The reason is that the public IP address used for web hosting is assigned by the 1st provider and is not routable via the 2nd provider's link. When the 1st link goes down, the web server's public IP becomes unreachable. To avoid this, use a public IP range that is provider-independent or implement DNS-based failover with a secondary IP.

13

Where do your strengths lie with wireless network engineering? Where do you want to improve?

Reference answer

This question asks the candidate to self-assess their technical strengths in wireless engineering (e.g., security, design, troubleshooting) and identify areas for professional development.

14

What is data encapsulation in networking?

Reference answer

Data encapsulation is a process in which data is packaged and labelled for accurate and efficient transmission over a network. It's a key part of the layered network architecture models, such as the TCP/IP or OSI models. Here's a high-level view of what happens during data encapsulation: At the highest layer (like the Application layer in the OSI model), data is generated from a user application, like an email or a web page request. As the data descends each layer of the model, it gets wrapped or 'encapsulated' in protocol information for that layer. Each layer provides specific services, and the protocol data added to the original payload can include addresses, control information, error checking fields, sequence numbers, and more. For instance, at the Transport Layer, segments with additional headers for transport specific features (like sequence number for reassembling packets in the correct order) are created. At the Network Layer, these segments are packed into packets with IP headers that include source and destination IP addresses. Finally, at the Data Link Layer, these packets are encapsulated into frames, with headers and footers for network interface operations, like MAC addresses and error checking fields. These frames are then sent over the physical network (like Ethernet or Wi-Fi). At the receiving end, this process is reversed, in a procedure known as de-encapsulation. The protocol-specific headers and footers added at each layer get stripped off at the corresponding layer, eventually restoring the original data at the top layer. This process ensures efficient and orderly transmission and receiving of data over the network.

15

Which of the following TCP port numbers is commonly associated with the Secure Shell (SSH) protocol?

Reference answer

22

16

What is a network packet and why is it important?

Reference answer

A network packet is a small unit of data transmitted over a network. Each packet contains a portion of the data being sent, along with metadata such as the destination address. Packets are important because they enable efficient and organized data transmission over networks, allowing large amounts of data to be broken into manageable chunks for delivery.

17

What is a VLAN and Why do We Use it?

Reference answer

A VLAN (Virtual Local Area Network) is a logical segmentation of a physical network that separates broadcast domains within a switch. There are various reasons to use Virtual LANs. First of all VLANs are important for security. We can divide different departments traffic with VLANs. This also provides broadcast traffic reduce. Instead of one large network, we can divide our network into smaller parts. By doing this network management become easier. Follow-up Question: What is the difference between an access port and a trunk port? Access Port is a port which belongs to one VLAN and carries traffic for that VLAN. It is used for end devices like PCs and printers. Trunk Port is a port that carries traffic for multiple VLANs between switches. VLAN information is preserved using VLAN tagging (802.1Q). Follow-up Question: Can devices in different VLANs communicate directly? No, they cannot. Because the devices in different VLANs are in separate broadcast domains. Here, Inter-VLAN Routing is required. There are two ways to use Inter-VLAN Routing: Using a Router or using a Layer 3 switch to use Switch Virtual Interfaces.

18

Differentiate between Ad-Hoc and Infrastructure topology and also explain with their advantages and disadvantages?

Reference answer

Wireless networks typically work in one of two configurations: Ad-Hoc or Infrastructure. 1) Ad-Hoc is Latin meaning “for this purpose” so these are the networks which are basically created for some purpose. So these are the group of workstations which communicate directly witch each other to exchange information. An Ad-Hoc network is also called as a peer to peer network. Here are some benefits of an Ad-Hoc network are:- a) The possibilities with Ad-Hoc network are quite endless. b) Ad-Hoc networks are simple to set up. c) Ad-Hoc networks are inexpensive. d) Ad-Hoc networks are fast. Disadvantages of an Ad-Hoc network are as follows:- a) It is not able to get into the mainstream wired local area network. b) It needs more technology to support their reliability. c) As the network increases its speed slows down considerably. 2) In Infrastructure mode, network includes an access point when the wireless clients connect to an access point, which in turn bridges to a network. Infrastructure network can pass information through a central information hub which can be both, hardware or software device on a computer. So under this devices in a wireless network are set up to communicate through an access point. An infrastructure network enables you to:- a) In this you do not have to control over the path your data takes. b) Connect to a wired network. c) Extend your wireless network's range. d) Utilize roaming ability. Disadvantages for Infrastructure network are:- 1. Use of more wireless access points. 2. This increase the cost of implementing a wireless network solution.

19

What is the TCP three-way handshake?

Reference answer

The TCP/IP handshake, or TCP three-way handshake, is a process used to establish a connection between two devices over a network before data is sent. It's named a "three-way handshake" because it involves three parts: SYN, SYN-ACK, and ACK. Here's how it works: The device initiating the connection (client) sends a SYN (synchronize) message to the other device (server). This message includes an initial sequence number for tracking data packets. The server then acknowledges receipt of the SYN message by sending back a SYN-ACK (synchronize-acknowledge) message. This message includes both an acknowledgement number (the initial sequence number from the client, increased by one) and a new sequence number for the server's own data packets. Finally, the client sends an ACK (acknowledge) message back to the server with the server's sequence number increased by one. This confirms that it correctly received the server's SYN-ACK message. This process of SYN, SYN-ACK, and ACK confirms that both devices are ready to exchange data and have the right sequence numbers. Once the handshake is completed, the TCP/IP connection is established, and data transfer can commence. The three-way handshake is crucial for initiating a reliable, ordered transfer of data between networked devices.

20

Tell us about the biggest network youâve engineered

Reference answer

Interviewers will typically ask these types of network engineer interview questions as they'll want to know if you have experience designing, implementing and troubleshooting networks similar to or the same size as the networks they and their clients use. When it comes to these types of network engineer interview questions and answers, here's an example of a response you could give: âAmong 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.â Even if you have yet to work on networks of the same scale, this won't necessarily mean you won't fit the employer's requirements. Your enthusiasm and other credentials will always be taken into account.

21

Imagine a scenario where an RF system experiences intermittent faults. What troubleshooting techniques would you employ to identify and rectify these faults?

Reference answer

The candidate should provide strategies to identify and solve intermittent issues, which are often challenging. The response should illustrate their analytical skills and ability to work with complex and unpredictable RF environments.

22

Why Bandwidth is important to network performance parameters?

Reference answer

Bandwidth is characterized as the measure of data or information that can be transmitted in a fixed measure of time. The term can be used in two different contexts with two distinctive estimating values. In the case of digital devices, the bandwidth is measured in bits per second(bps) or bytes per second. In the case of analog devices, the bandwidth is measured in cycles per second, or Hertz (Hz). Bandwidth is only one component of what an individual sees as the speed of a network. True internet speed is actually the amount of data you receive every second and that has a lot to do with latency too.

23

What is the maximum data rate specified for IEEE 802.11b WLANs?

Reference answer

Up to 11 Mbit.

24

How do you approach disaster recovery and business continuity planning for network infrastructure?

Reference answer

DR planning starts with understanding the business's tolerance for downtime and data loss. I work with business continuity teams to define RTO (Recovery Time Objective) and RPO (Recovery Point Objective) for different systems, then I design the network to meet those requirements. For critical systems, I implement redundancy at multiple levels: redundant uplinks to our ISP, dual core switches with automatic failover, and backup connectivity through a secondary carrier. I also design the DR site's network to mirror production, so failover can happen automatically if needed. I test this annually through full DR exercises—this is crucial because untested DR plans don't work. In my last role, we discovered during a test that our backup carrier's QoS wasn't sufficient for VoIP traffic. We found that out in a controlled test, not during an actual emergency.

25

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

26

How does Wi-Fi work?

Reference answer

Wi-Fi allows devices to connect to a network wirelessly using radio waves. It's essentially like a walkie-talkie, but for data. A Wi-Fi router acts as a base station, transmitting and receiving data. Your devices (laptops, phones, etc.) have Wi-Fi adapters that can send and receive these radio waves, allowing them to communicate with the router and, subsequently, the internet. Data is encoded onto these radio waves using specific protocols (like 802.11a/b/g/n/ac/ax) and frequencies. When your device wants to send data, it converts it into radio waves and transmits them. The router receives these waves, decodes the data, and forwards it to the internet (or another device on the network). The reverse process happens when the router receives data from the internet and transmits it to your device.

27

How do you identify interference sources in a network?

Reference answer

To identify interference sources in a network, use spectrum analyzers or tools like Ekahau and AirMagnet to detect RF interference. Check for overlapping channels from neighboring networks and identify non-Wi-Fi devices such as microwaves or Bluetooth equipment causing noise. Mitigate interference by adjusting channels, AP placement, or band usage to improve network performance.

28

What is Multicast?

Reference answer

Multicast is a method of group communication where the sender sends data to multiple receivers or nodes present in the network simultaneously. Multicasting is a type of one-to-many and many-to-many communication as it allows sender or senders to send data packets to multiple receivers at once across LANs or WANs. This process helps in minimizing the data frame of the network. For more details please read Multicasting in computer network article.

29

What is a network, and why is it important?

Reference answer

A network is a group of connected devices, like computers, servers, and printers, that communicate with each other to share data and resources. Networks help businesses and individuals connect to the internet, share files, and use services like cloud storage, making communication and data transfer more efficient.

30

What is Symmetric and Asymmetric Encryption?

Reference answer

- Symmetric Key Encryption: Encryption is a process to change the form of any message in order to protect it from reading by anyone. In Symmetric-key encryption the message is encrypted by using a key and the same key is used to decrypt the message which makes it easy to use but less secure. It also requires a safe method to transfer the key from one party to another. - Asymmetric Key Encryption: Asymmetric Key Encryption is based on public and private key encryption techniques. It uses two different keys to encrypt and decrypt the message. It is more secure than the symmetric key encryption technique but is much slower. For more details please refer difference between symmetric and asymmetric encryption articles.

31

How would you assess a client's needs when optimising a network?

Reference answer

Your potential employer will consider its clients one of the business's most important assets. Therefore, they'll want to know you have their client's needs at the forefront of everything you do. When answering these types of network engineer interview questions, the interviewer wants you to explain how you would collate and analyse the client's requirements concerning their network. As part of your network engineer interview preparation, hereâs how you can answer this question: âWhen tasked with creating or enhancing a customer's network, I adopt an inquisitive approach. During the initial stages, I invest time in asking a multitude of questions to gain a comprehensive understanding of the clientâs needs and expectations. Once Iâve gathered and clarified all this information, Iâll then proceed to formulate a solution that aligns with their specific needs. Iâll use this process to ensure that the end result meets or exceeds the clientâs expectations and provides the best possible network solution tailored to their specific goals.â

32

How do configuration management tools like Ansible, Puppet, or Chef help in network management?

Reference answer

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

33

What is a wireless mesh network?

Reference answer

A wireless mesh network connects APs without wired backhaul. One root AP connects to the wired network, and other non-root APs forward traffic wirelessly. This is useful for large outdoor campuses or areas where wiring is difficult.

34

What is Wi-Fi and how does it work?

Reference answer

Wi-Fi uses radio waves to provide wireless network connectivity between devices within hotspots near wireless routers. A hotspot is a physical location that provides internet access using Wi-Fi technology.

35

What is a network packet?

Reference answer

A network packet is a unit of data transmitted over a network. It contains information such as the source and destination IP addresses, data payload, and protocol information. Packets are routed and forwarded through network devices based on their destination addresses.

36

What is a private IP address?

Reference answer

Here's our recommended way to respond to this type of network engineer question that an interviewer may ask you to further understand your technical expertise. "Private IP addresses are designated for use within intranets and serve as non-routable internal network addresses on external public networks. The purpose of private IP addresses is to prevent conflicts within internal networks, ensuring smooth communication and operation. Additionally, the same range of private IP addresses can be reused for multiple intranets, as they remain isolated, enabling efficient and secure utilisation across various internal network environments."

37

Changes in WLAN-11ac compared to previous versions?

Reference answer

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

38

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.

39

Which layer of the OSI model is responsible for determining the best path for data transmission?

Reference answer

The Network layer (Layer 3) of the OSI model is responsible for determining the best path for data transmission.

40

What is Hierarchical Network Architecture?

Reference answer

Hierarchical Network Architecture is a design model that divides a network into distinct layers, typically including the core layer (high-speed backbone), distribution layer (policy-based connectivity and routing), and access layer (user and device connectivity). This structure improves scalability, manageability, and performance by separating functions into modular tiers.

41

Explain the TCP three-way handshake.

Reference answer

The three-way handshake happens as: - SYN: The client sends a synchronization request to start a connection. - SYN-ACK: The Server acknowledges and sends a synchronization request. - ACK: The client acknowledges the server's request and completes the handshake.

42

What is a cloud network?

Reference answer

A cloud network is a virtualized network infrastructure hosted on a cloud computing platform. It provides on-demand access to networking services, such as virtual routers, switches, and firewalls, without the need for physical hardware.

43

How much is the distance and data rate supported in WLAN devices?

Reference answer

There are different distances and data rates available in WLAN devices based on the IEEE standard they are supporting.

44

What is a switch and how is it different from a hub?

Reference answer

A switch is a device that connects multiple devices on a local network and uses MAC addresses to forward data only to the intended recipient. A hub, on the other hand, broadcasts data to all devices on the network, regardless of the destination. For example, a switch is more efficient and secure compared to a hub.

45

Which of the multiplexing techniques is used to combine digital signals?

Reference answer

To combine digital signals, time division multiplexing techniques are used.

46

In the previous scenario, Changing of Default Gateway on User LAN and APP Server LAN is not possible. What could be the workaround (configuration is only possible at Network devices and not endpoints) with minimal changes in devices?

Reference answer

A workaround is to use Policy-Based Routing (PBR) on the Layer 3 switch or router to redirect traffic from the User LAN to the Firewall. For example, configure a PBR rule on the switch's VLAN interface to forward all traffic destined for the Application Server subnet to the Firewall's IP address.

47

Explain the differences between time-domain and frequency-domain analysis in RF signal processing. When would you use each method?

Reference answer

Expect an in-depth explanation of the two domains, their significance, and appropriate contexts to apply each for efficient signal analysis.

48

What is the protocol and port no of DNS?

Reference answer

Protocol - TCP/UDP Port number- 53

49

What are the recommended channels if you are setting up three WLANs and want minimum interference over there?

Reference answer

1) There is a need of selecting the channels for setting up WLANs, to communicate; all the components of a Wi-Fi network must use the same channel. In the Wi-Fi network in infrastructure mode (using an access point), it depends on the channel set at the access point. 2) For better results when using Wi-Fi, it is necessary to adjust the channel on the access point as well as configured on the client, to take the least use channel in your neighbourhood. 3) To do this you can use software such as NetStumbler, which will list the neighbourhood Wi-Fi networks and channels used. Note:- The channels most frequently used to select one as free as possible. So the recommended channels are as follows:- Channel 1: 2.412 MHz Channel 2: 2.417 MHz Channel 3: 2.422 MHz Channel 4: 2.427 MHz Channel 5: 2.432 MHz Channel 6: 2.437 MHz You can choose from these channels while setting up the WLANs.

50

How is sending a letter similar to how computers send data over a network?

Reference answer

Sending a letter is similar to how computers send data over a network in several ways. Both involve breaking down a larger message into smaller, manageable units (packets in networking, pages/sections in a letter). The letter needs an address (IP address) to ensure it reaches the correct recipient, just like data packets do. The sender (computer sending data) relies on a system (postal service/network protocols) to deliver the message reliably. Finally, just like a letter might have a return address, data packets often contain information about the sender for acknowledgements or replies. Consider a scenario where some pages of a letter get lost in transit. Networking protocols like TCP have mechanisms to detect lost packets and request retransmission, ensuring reliable delivery, similar to resending missing pages of the letter.

51

What is the difference between static routing 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, on the other hand, uses algorithms and protocols like OSPF or EIGRP to automatically adjust paths based on network conditions. It adapts to changes more efficiently and reduces administrative overhead, but it may be more complex and resource-intensive to manage.

52

What is DSSS and CCK modulation scheme?

Reference answer

Direct Sequence Spread Spectrum (DSSS) and Complementary Code Keying (CCK) are modulation schemes employed in WLAN devices compliant with IEEE 802.11b.

53

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

Reference answer

The frequency range of IEEE 802.11g is 2.4 GHz.

54

What is MPLS, and how does it enhance network performance?

Reference answer

MPLS (Multi-protocol Label Switching) uses labels to make forwarding decisions, improving network efficiency and performance. The MPLS header is typically 32 bits long. It is used to manage traffic engineering and provide quality of service (QoS). Example: MPLS Label Assignment Process - Label Assignment: Router A receives an IP packet and assigns an MPLS label to it. For example, Router A assigns the label 1001. - Label Forwarding: - Router A forwards the packet with the MPLS label 1001 to Router B. - Router B receives the packet, looks up the MPLS label 1001, and forwards the packet to Router C based on its label forwarding table. 3. Label Removal: Router C finally removes the MPLS label and forwards the original IP packet to its destination.

55

Why is QoS important in enterprise wireless networks?

Reference answer

Quality of Service (QoS) is important because it prioritizes critical traffic such as VoIP, video conferencing, and mission-critical applications over regular data traffic. Without QoS, latency-sensitive applications can experience packet loss, jitter, and delays, leading to degraded performance and poor user experience in enterprise environments.

56

What is a network security incident?

Reference answer

A network security incident is any event that compromises the security of a network. It can include unauthorized access, data breaches, malware infections, denial-of-service attacks, or other malicious activity that affects the confidentiality, integrity, or availability of network resources.

57

Describe a complex network design project you have managed. What challenges did you face and how did you overcome them?

Reference answer

At SingTel, I led the design and implementation of a multi-site VPN for a large client. We faced significant challenges with integrating various legacy systems. By facilitating open communication between teams and conducting thorough risk assessments, we successfully delivered the project on time, resulting in a 30% improvement in network performance and a 25% reduction in operational costs.

58

In your experience, what are common causes of RF system performance degradation over time and how do you address them?

Reference answer

The candidate should cite real-world examples of performance degradation causes and the remedial actions they took or suggest. This helps to determine their experience level and knowledge depth in maintaining RF system performance.

59

How does network segmentation improve security?

Reference answer

Network segmentation divides a network into smaller, isolated segments. This limits the blast radius of security breaches; if one segment is compromised, the attacker's access is confined, preventing lateral movement to other critical parts of the network. By isolating sensitive data and systems within their own segments, you can implement stricter access controls and monitoring, enhancing overall security. Key benefits include: reduced attack surface, improved threat containment, enhanced compliance, and simplified security management.

60

What is MIMO, SU-MIMO, MU-MIMO, Beamforming etc

Reference answer

These are some of the most common terms you will come across while reading content on 11n and 11ac. The books i have referenced have all you need on these concepts

61

What techniques do you employ to ensure the accurate calibration of RF measurement instruments?

Reference answer

The candidate is expected to discuss specific calibration procedures, the importance of calibration in signal analysis, and how they ensure precision and accuracy in their measurements.

62

How do you troubleshoot a wireless network issue where devices are unable to connect?

Reference answer

To troubleshoot wireless connectivity issues: - - Check the SSID and password for correctness. - Verify that the access point is powered on and operational. - Ensure there is no interference from other devices or physical obstructions. - Check for IP address conflicts and DHCP settings. - Review the access point's configuration and firmware for updates.

63

What is handover in cellular networks?

Reference answer

Handover is the process of transferring an ongoing call or data session from one cell to another as the user moves. It ensures seamless communication without dropping connections as users move through different coverage areas.

64

When dealing with multipath interference in an RF communication link, what methods would you use to mitigate its effects?

Reference answer

The candidate's response should include techniques like antenna placement, diversity schemes, or digital signal processing methods, showing expertise in practical RF problem-solving.

65

What are some performance optimization tips for enterprise wireless networks?

Reference answer

Performance optimization in enterprise wireless networks includes: - Enable load balancing to distribute clients. - Monitor throughput and latency regularly. - Use Quality of Service (QoS) to prioritize critical applications like VoIP or video conferencing. These practices help maintain reliable performance in high-demand enterprise environments.

66

What is FTP and how does it work?

Reference answer

FTP, or File Transfer Protocol, is a standard network protocol that allows files to be transferred over the internet from one computer to another. It's basically a set of rules that define how files should move between devices on a network. FTP operates on a client-server model. The client initiates a connection with the server to request files or to send files. To start this file transfer, a user usually needs to log in to the FTP server, although some servers may provide guest or anonymous access. A notable feature of FTP is that it uses two separate connections for data transfer and control commands, ensuring that the file transfers are robust and reliable. This protocol is widely used for transferring large files or for uploading files to a server. However, it's worth noting that data transferred using FTP is not encrypted, and it can be intercepted in transit. So, for sensitive data, it might be better to use versions of FTP that employ security measures, like FTPS or SFTP, which use encryption for data transfer.

67

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

Reference answer

Preshared key (used at home, easy but lacks control) and 802.1x and EAP (used for serious setups, allows user authentication).

68

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.

69

How do I Identify When an IP Address is Private or Public?

Reference answer

You can identify private IP addresses by checking if they fall within the reserved ranges (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)

70

Name some services provided by the application layer in the Internet model?

Reference answer

Some services provided by the application layer in the Internet model are as follows: - Mail services - Directory services - File transfer - Access management - Network virtual terminal

71

Can you explain the importance of redundancy in network design?

Reference answer

Redundancy is crucial in network design to ensure continuous availability and minimize downtime during hardware failures or unexpected outages. By implementing backup systems and failover mechanisms, we can maintain service continuity and protect against data loss.

72

What is a subnet mask?

Reference answer

A subnet mask is employed to split an IP address into its network and host segments. It aids in determining the network to which an IP address is associated. For instance, with the IP address 192.168.1.10 and a subnet mask of 255.255.255.0, the network portion is 192.168.1, while the host portion is 10.

73

Explain the concept of channel fading.

Reference answer

Channel fading refers to the variation in the strength of the received signal due to factors like multipath propagation, interference, and movement of the transmitter or receiver. Fading affects the reliability of the communication link.

74

How do you handle network redundancy and failover?

Reference answer

Network redundancy and failover are handled by implementing multiple pathways for data to travel, using technologies like redundant hardware, load balancing, and failover protocols. For example, I use dual routers and switches with automatic failover to ensure continuous network availability in case of hardware failure.

75

Please can you define what DNS means?

Reference answer

Hereâs how to answer another type of network engineer interview question an interviewer could ask to support their judgement of your technical know-how. âThe Domain Name System, commonly known as DNS, serves as a network service primarily responsible for converting host names into TCP/IP addresses for seamless address resolution.â

76

How do you ensure network security in your designs?

Reference answer

I adhere to the NIST Cybersecurity Framework when designing networks, ensuring that security is built-in from the start. For instance, in a project with a financial client, I implemented a layered security approach, including firewalls, intrusion detection systems, and regular vulnerability assessments. This reduced potential security incidents by 40% over the first year. I also maintain certifications in CISSP and CCNP Security to stay current with best practices.

77

What are the best practices for network capacity planning?

Reference answer

I ensure effective network capacity planning by analyzing current usage, forecasting future demands, and implementing scalable solutions. This prevents congestion, optimizes resources, and ensures seamless performance. There are several key best practices: - Traffic Analysis: Continuously monitor bandwidth usage to identify trends and peak times. - Growth Forecasting: Estimate future capacity needs based on business expansion and technology upgrades. - Scalability Planning: Design the network to accommodate increased traffic without performance degradation. - Redundancy Implementation: Use backup links and failover mechanisms to prevent downtime. - Load Balancing: Distribute traffic efficiently to avoid congestion and optimize resource utilization. - Regular Audits: Periodically assess network performance and adjust capacity as needed.

78

What is network security and why is it important?

Reference answer

Network security is a broad term that encompasses the strategies and measures designed to protect the integrity, confidentiality, and accessibility of computer networks and data using both software and hardware technologies. It's all about defending your network from a variety of threats, such as hackers, malware, and denial-of-service attacks. Every organization that uses a computer network should have some level of network security in place. This can include solutions like firewalls to filter out malicious traffic, antivirus software to detect and nullify threats, and encryption to scramble data so it can't be understood if intercepted. Network security also involves practices and policies that network admins follow to prevent and monitor unauthorized access, misuse, or modifications. This can include educating employees about safe online habits, limiting access rights to the network, and regularly updating software to patch vulnerabilities. In essence, network security is a critical aspect of IT that keeps networked data safe, allowing businesses, government entities, and individuals to conduct their online activities securely.

79

What is a router and what is its main job?

Reference answer

A router is a networking device that forwards data packets between computer networks. It acts as a traffic controller, selecting the best path for data to travel to its destination. The main job of a router is to connect multiple networks and forward data packets between them. It does this by examining the destination IP address of each packet and using routing tables to determine the optimal path to send it. This ensures efficient and reliable communication across different networks, whether it's a local network or the internet.

80

Describe a time when you implemented advanced security measures to protect a network. What challenges did you face, and how did you overcome them?

Reference answer

In a previous role, I led a project to enhance our network's security posture in response to emerging threats. The steps I took included: - Threat Assessment: Conducted a comprehensive risk analysis to identify vulnerabilities. - Next-Generation Firewalls: Advanced firewalls with intrusion prevention capabilities were deployed. - Network Segmentation: Implemented VLANs to isolate sensitive data and limit lateral movement. - Multi-Factor Authentication (MFA): Enforced MFA across all critical systems to enhance access control. - Security Information and Event Management (SIEM): Integrated an SIEM system for real-time monitoring and incident response.

81

How do you set up alerts for network issues?

Reference answer

To set up alerts for network issues, network engineers typically use network management software to define thresholds for key performance indicators like bandwidth usage, latency, and error rates. When thresholds are breached, the software triggers alerts via email, SMS, or dashboard notifications.

82

What is the difference between a MAC address and an IP address?

Reference answer

A MAC (Media Access Control) address is a unique identifier assigned to a network interface card (NIC) for communication within a local network. It operates at the data link layer. An IP (Internet Protocol) address, on the other hand, identifies devices across different networks and operates at the network layer. MAC addresses are permanent, while IP addresses can change.

83

What are effective strategies for network performance optimization in large-scale deployments?

Reference answer

Effective strategies include capacity planning, traffic analysis, QoS configurations, WAN optimization, load balancing, and regular performance monitoring to proactively identify and resolve bottlenecks.

84

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.

85

Discuss your experience with the homologation process for RF devices and how you have ensured successful certification in multiple countries.

Reference answer

The candidate should be familiar with homologation processes and be able to discuss practical examples of how they navigated different country requirements to achieve device certification.

86

What are some tips for handling wireless network design scenarios in interviews?

Reference answer

Tips for handling wireless network design scenarios in interviews include: - In auditoriums or high-density areas, deploy multiple APs using 5 GHz channels for better performance - In offices with thick walls, consider directional antennas or additional APs to ensure coverage - Validate your design using simulations or site surveys before deployment - Provide examples from labs, simulations, or real-world experience to illustrate your approach - Walk interviewers step-by-step through your problem-solving methodology - Practice scenario-based answers multiple times to build confidence and fluency These strategies help demonstrate both technical expertise and practical design experience in interviews.

87

What are the key differences between IPv4 and IPv6?

Reference answer

IPv4 and IPv6 are both protocols used for sending data across networks, but there are several key differences between them: Address Length: The most noticeable difference is the length of the IP addresses. IPv4 uses 32-bit addresses, which gives us a little over 4 billion unique addresses. In contrast, IPv6 uses 128-bit addresses. That's a huge number of possible addresses, helping alleviate concerns about IP address exhaustion. Address Format: IPv4 addresses are displayed in decimal format, separated by periods (for example, 192.0.2.0). IPv6 addresses, on the other hand, are shown in hexadecimal and separated by colons, like 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Header Structure: The IPv6 header has a simpler structure than the IPv4 header, which can streamline processing and improve performance. One noticeable change is that in IPv6, the checksum field is eliminated because error checking is handled by the transport layer. Auto-configuration: IPv6 has an auto-configuration capability that allows devices to automatically configure an IP address and other parameters without needing a server or manual configuration. These changes make IPv6 better at catering to the growing number of internet devices and more efficient at handling data traffic. However, migration to IPv6 is a slow process because it requires significant changes to network infrastructure.

88

Explain the concept of a VLAN

Reference answer

Virtual local area network, also known as VLAN divides a large network into smaller independent sections. A device in one VLAN communicates with another device in the same VLAN, as though it is in its own bubble, despite existing in the same physical system. This makes things neat and safe. When a problem, such as a virus, occurs in one VLAN, it remains there and does not propagate. It also decreases network congestion; data travels at a higher rate. VLANs simplify management of networks without additional hardware or cables requirements. They are an intelligent means of managing devices, improving security and keeping things going effortlessly.

89

What is an SSID and why is it important?

Reference answer

SSID (Service Set Identifier) is the unique name assigned to a Wi-Fi network, distinguishing it from other networks in the area. It enables users to identify and connect to the correct network, ensuring secure and organized access. Properly naming SSIDs helps manage multiple networks, prevents unauthorized access, and can be used to communicate network information, such as usage policies or ownership.

90

Which spread spectrum technology does the 802.11b standard define for operation?

Reference answer

802.11b uses Direct Sequence Spread Spectrum (DSSS).

91

What role does spectrum analysis play in RF troubleshooting, and what information can it provide?

Reference answer

The expectation is that the candidate will showcase their understanding of the spectrum analyzer's role in identifying signal problems and their ability to interpret the collected data.

92

What is the difference between a managed and unmanaged switch in a wireless network?

Reference answer

A managed switch provides advanced features like VLANs, QoS, and network monitoring, allowing for greater control and configuration. An unmanaged switch offers basic connectivity without configuration options, suitable for simpler network setups.

93

What are the different types of network cables and their uses?

Reference answer

There are several types of network cables, each suited for different applications. Ethernet cables, like Cat5e, Cat6, and Cat6a, are commonly used for local area networks (LANs) to connect computers, routers, and switches. They transmit data using electrical signals and are categorized based on their speed and bandwidth capabilities, with Cat6 and Cat6a supporting higher speeds and frequencies than Cat5e. Fiber optic cables transmit data as light pulses, making them ideal for long distances and high-bandwidth applications. They are less susceptible to interference and can support much higher data rates than Ethernet cables. Fiber optic cables are used in wide area networks (WANs), metropolitan area networks (MANs), and in data centers for interconnecting servers and network equipment.

94

How do you ensure a smooth cloud migration without disrupting business operations?

Reference answer

I ensure a smooth cloud migration by conducting thorough assessments, implementing a phased migration strategy, and using hybrid cloud setups for minimal downtime. I leverage automated tools for data synchronization, ensure robust security controls, and perform extensive testing before cutover. Continuous monitoring and rollback plans further mitigate risks, ensuring seamless business operations during migration.

95

How do you troubleshoot RF issues?

Reference answer

This question assesses the candidate's expertise in radio frequency (RF) troubleshooting, including techniques like spectrum analysis, site surveys, and identifying sources of interference.

96

What is DNS and why is it important?

Reference answer

DNS, or Domain Name System, translates human-readable domain names (like google.com) into IP addresses (like 142.250.185.142), which computers use to identify each other on the internet. Think of it as the internet's phone book. It's important because without DNS, you'd have to remember and type in IP addresses every time you wanted to visit a website. DNS makes the internet user-friendly by allowing us to use easy-to-remember domain names. It also provides redundancy and allows websites to change IP addresses without disrupting service, since the DNS record can be updated to point to the new address.

97

What is IP Spoofing?

Reference answer

IP Spoofing is essentially a technique used by hackers to gain unauthorized access to Computers. Concepts of IP Spoofing were initially discussed in academic circles as early as 1980. IP Spoofing types of attacks had been known to Security experts on the theoretical level. It was primarily theoretical until Robert Morris discovered a security weakness in the TCP protocol known as sequence prediction. Occasionally IP spoofing is done to mask the origins of a Dos attack. In fact, Dos attacks often mask the actual IP addresses from where the attack has originated from.

98

How are automation and orchestration utilized in modern network design?

Reference answer

Automation and orchestration are utilized through infrastructure-as-code, automated provisioning, configuration management tools, centralized policy enforcement, and self-healing mechanisms to promote agility, consistency, and reduced operational overhead.

99

What is the difference between IPS and a firewall?

Reference answer

The Intrusion Prevention System is also known as Intrusion Detection and Prevention System. It is a network security application that monitors network or system activities for malicious activity. The major functions of intrusion prevention systems are to identify malicious activity, collect information about this activity, report it, and attempt to block or stop it. Intrusion prevention systems are contemplated as augmentation of Intrusion Detection Systems (IDS) because both IPS and IDS operate network traffic and system activities for malicious activity. IPS typically records information related to observed events, notifies security administrators of important observed events, and produces reports. Many IPS can also respond to a detected threat by attempting to prevent it from succeeding. They use various response techniques, which involve the IPS stopping the attack itself, changing the security environment, or changing the attack's content. A firewall is a network security device, either hardware or software-based, which monitors all incoming and outgoing traffic, and based on a defined set of security rules it accepts, rejects, or drops that specific traffic.

100

What is the significance of using channel width in wireless networks?

Reference answer

Channel width affects the data rate and bandwidth of a wireless network. Wider channels (e.g., 40 MHz, 80 MHz) provide higher throughput but can also increase interference. Properly selecting channel width helps balance performance and interference.

101

What is network design?

Reference answer

Network design is the process of planning, creating, and implementing a network infrastructure to meet the specific needs of an organization. It involves analyzing requirements, selecting appropriate hardware and software, and configuring the network to ensure optimal performance, security, and scalability.

102

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.

103

Explain the OSI model in detail.

Reference answer

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers. Each layer has a specific function and interacts with the layers directly above and below it. Here's a brief overview of each layer: Application (Layer 7), Presentation (Layer 6), Session (Layer 5), Transport (Layer 4), Network (Layer 3), Data Link (Layer 2), Physical (Layer 1).

104

What are common wireless security protocols?

Reference answer

The common wireless security protocols are: - WPA2: Strong encryption using AES, commonly used in enterprise networks. - WPA3: Newer standard, stronger encryption, and protection against dictionary attacks. - 802.1X: Port-based network access control requiring users to authenticate via RADIUS servers.

105

How do we prevent loops on the WLC?

Reference answer

STP (Spanning Tree Protocol): Enabled to prevent network loops.

106

How many IFSs are there? Where can we use these? Which IFS is the shortest? Which IFS is variable?

Reference answer

♣ There are 6 IFSs are there. RIFS, SIFS, PIFS, DIFS, AIFS, EIFS. ♣ In short => RIFS: 11n, SIFS: Between Data and ACK, PIFS: Urgent frame transmission, AIFS: WMM enabled client, EIFS: For Retransmitted]. ♣ RIFS->2us. ♣ AIFS->Depends on AIFSN. ♠ For detailed explanation : IFS

107

What is a transparent bridge?

Reference answer

Transparent Bridge: A transparent bridge automatically maintains a routing table and updates tables in response to maintaining changing topology. The transparent bridge mechanism consists of three mechanisms: - Frame forwarding - Address Learning - Loop Resolution The Transparent bridge is easy to use. Install the bridge and no software changes are needed in the hosts. In all the cases, transparent bridges flooded the broadcast and multicast frames.

108

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

109

What are the key components of a data center network architecture?

Reference answer

Key components include core switches, distribution switches, access switches, routers, firewalls, load balancers, and storage networks. For example, in a data center, core switches handle high-speed data transfer, distribution switches manage traffic between core and access layers, and firewalls protect against unauthorized access.

110

What is encryption and how is it used in network security?

Reference answer

Encryption is the process of converting plaintext into a coded format to prevent unauthorized access. It is used in network security to protect sensitive data during transmission and storage, ensuring that even if data is intercepted, it cannot be read without the proper decryption key.

111

Can you describe a scenario where you used scripting to solve a network problem?

Reference answer

Here, candidates might describe scenarios such as: Writing a Python script to automatically allocate IP addresses; Creating a script to parse and analyze network logs, identify patterns, and highlight errors; Using a script to periodically ping devices and measure latency, packet loss, and jitter; Developing a script to automate the backup and deployment of network device configurations. Look for answers including detailed information about the problem, the scripting language candidates used, the specific functions of the script, and the outcome they achieved.

112

Describe a challenging situation you faced while designing or testing a wireless protocol and how you resolved it.

Reference answer

The candidate is expected to demonstrate problem-solving skills and practical knowledge in dealing with real-world RF engineering issues related to wireless protocols.

113

Suppose a product fails to meet a specific RF compliance requirement during pre-certification testing. What steps would you take to rectify the issue?

Reference answer

Candidates should show their problem-solving skills by outlining a systematic approach to troubleshooting, redesign, and retesting to ensure the product meets the necessary compliance standards before official certification.

114

What is the difference between a private and a public IP address?

Reference answer

A public IP address is assigned by an internet service provider (ISP) and is used to identify a device on the internet. It allows devices to communicate globally. A private IP address is used within a local network (e.g., in homes or offices) and cannot be accessed directly from the internet. Routers use Network Address Translation (NAT) to allow private IP addresses to connect to the internet using a single public IP.

115

What is the noise figure, and why is it important in RF design?

Reference answer

This question should assess the candidate's understanding of noise figure and its impact on signal clarity. The candidate should explain how a higher noise figure reduces the overall quality of the signal. Look for their familiarity with techniques to minimize noise, like using low-noise amplifiers and fine-tuning circuit components to reduce noise.

116

What is a network protocol?

Reference answer

A network protocol is a set of rules that govern how devices communicate over a network. It defines the format, order, and meaning of messages exchanged between devices. Essentially, it's a standardized way for devices to understand each other. For example, HTTP (Hypertext Transfer Protocol) is a network protocol used for transferring data over the web. When you access a website, your browser sends an HTTP request to the web server, and the server responds with an HTTP response containing the website's content.

117

Have you used network diagnostic tools like ping and traceroute?

Reference answer

Yes, I have used network diagnostic tools like ping and traceroute (or traceroute6 for IPv6). I've primarily used ping to verify basic network connectivity. For example, if I'm having trouble accessing a website, I would ping the website's IP address or domain name to see if my computer can reach the server. A successful ping indicates that the network path is up and that DNS resolution (if using a domain name) is working. I've used traceroute to diagnose network routing issues. If a website is slow or unreachable, traceroute helps to identify where the connection is failing or experiencing latency. It shows the path packets take from my machine to the destination and lists each hop (router) along the way, including the response time for each hop. This helps pinpoint bottlenecks or points of failure in the network path.

118

What are some common network monitoring tools?

Reference answer

Common network monitoring tools include: - SolarWinds Network Performance Monitor (NPM): For real-time network performance monitoring, fault detection, and troubleshooting. - PRTG Network Monitor: Offers comprehensive network monitoring capabilities, including bandwidth usage, device availability, and network traffic analysis. - Datadog: A cloud-based monitoring platform that provides comprehensive network monitoring, performance analytics, and security insights. - ManageEngine OpManager: A comprehensive network management tool that combines performance monitoring, fault management, and network configuration management.

119

What is a firewall?

Reference answer

A firewall is a security apparatus that oversees and regulates incoming and outgoing network traffic according to established security rules. It serves as a barrier between a trusted internal network and untrusted external networks. For example, a firewall can block unauthorized access while allowing legitimate traffic.

120

What is SNR? How do you fix SNR issues?

Reference answer

This question assesses the candidate's understanding of Signal-to-Noise Ratio (SNR), its impact on wireless performance, and techniques to improve it, such as reducing interference or optimizing antenna placement.

121

What is EIGRP and how does it compare to other routing protocols?

Reference answer

EIGRP (Enhanced Interior Gateway Routing Protocol) is a hybrid routing protocol combining features of distance-vector and link-state protocols. It uses the Diffusing Update Algorithm (DUAL) for rapid convergence and minimizes network disruptions. Unlike RIP, which has a hop limit and slower convergence, EIGRP supports classless routing, VLSM, and complex metrics. Compared to OSPF, EIGRP is easier to configure and scales well in diverse networks, though it is proprietary to Cisco devices, limiting its interoperability with non-Cisco equipment.

122

How do you optimize multicast traffic in an enterprise network?

Reference answer

Optimizing multicast traffic is crucial for efficient data distribution. My approach to optimizing multicast traffic in an enterprise network includes the following: - IGMP Snooping: Reducing unnecessary traffic by ensuring multicast traffic is only forwarded to subscribed hosts. - PIM Configuration: Choosing the appropriate PIM mode (Sparse or Dense) based on network topology. - RP Optimization: Using Anycast RP for redundancy and load balancing. - QoS for Multicast: Prioritizing multicast traffic to ensure smooth video and voice streaming. - Traffic Analysis: Monitoring multicast traffic using tools like Wireshark and NetFlow.

123

What is the difference between licensed and unlicensed spectrum?

Reference answer

Licensed spectrum is allocated by government authorities (like the FCC) and requires carriers to obtain licenses for operation. It's primarily used for services like cellular communication. Unlicensed spectrum is available for public use without licenses and is used for Wi-Fi, Bluetooth, and other short-range communication systems.

124

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

Reference answer

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

125

What do you understand by Sneakernet?

Reference answer

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

126

What are the main issues in wireless networks?

Reference answer

The main issues are: Coverage (need to place access points for proper signals), Interference (devices on 2.4 and 5GHz frequencies weaken signal quality), Privacy (data flies in the air, requiring strong authentication and encryption), and Regulations (restrictions on using wireless spectrum, with ISM bands like 902-928MHz, 2.4-2.4835 GHz, and 5 GHz).

127

What is the change in WLAN-11ac with respect to previous versions of WLAN?

Reference answer

WLAN-11ac has been introduced after previous versions of WLAN, which include 802.11a, 11b, 11g, and 11n. An 80MHz channel bandwidth is added. The number of MIMO streams has been enhanced to eight. 256QAM has been added.

128

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

129

What is the primary function of a DNS server and how does resolution work?

Reference answer

A DNS (Domain Name System) server's primary function is to translate human-readable domain names (like www.example.com) into IP addresses (like 192.0.2.1), which computers use to identify each other on a network. This translation process is called DNS resolution. The resolution process generally works as follows: 1. A user types a domain name into their browser. 2. The browser queries a DNS resolver (often provided by the user's ISP). 3. The resolver recursively queries other DNS servers, starting with root servers, then top-level domain (TLD) servers (like .com), and eventually authoritative name servers for the specific domain, until it finds the IP address associated with the domain name. 4. The resolver returns the IP address to the browser. 5. The browser then uses the IP address to connect to the web server hosting the website. DNS servers also cache responses to improve performance and reduce latency for future requests.

130

What is network security awareness training?

Reference answer

Network security awareness training educates users about common security threats, best practices, and company policies related to network security. It aims to raise user awareness of security risks and empower them to make informed decisions to protect themselves and the network.

131

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.

132

Why is Quality of Service (QoS) important in networking, and how is it implemented?

Reference answer

Quality of Service (QoS) prioritizes network traffic to ensure critical applications receive necessary bandwidth and low latency. QoS is essential for maintaining performance, particularly in voice and video applications. Implementation includes: - Traffic Classification: Identifying and categorizing network traffic. - Bandwidth Allocation: Reserving bandwidth for high-priority services. - Congestion Management: Implementing queuing mechanisms to avoid packet loss.

133

What are the considerations for designing a secure wireless network?

Reference answer

Considerations include using strong encryption protocols (WPA3), implementing robust authentication mechanisms, segmenting the network with VLANs, and regularly updating firmware. For example, a secure wireless network in an office would use WPA3 encryption, require user authentication, and separate guest and corporate traffic.

134

How do you approach designing a network that's both scalable and cost-effective?

Reference answer

I start by having detailed conversations with business stakeholders to understand growth projections, criticality of different systems, and budget constraints. Then I design in layers. For the core infrastructure, I over-provision slightly—maybe 30-40% extra capacity—because core upgrades are expensive and disruptive. For edge access, I build more flexibly using modular equipment that we can scale incrementally as needed. I also look for virtualization and cloud integration opportunities. In my last role, instead of buying expensive dedicated hardware for test environments, I proposed using VMware-based virtual networking. This cut infrastructure costs by 25% while actually improving our agility.

135

Describe a time when you disagreed with a business decision regarding network architecture. How did you handle it?

Reference answer

The CTO wanted to save money by consolidating all traffic—data, voice, and video—over a single network link to our remote office. I disagreed because our application performance would suffer, and VoIP quality would degrade unpredictably. Rather than just saying ‘no,' I gathered data. I modeled the traffic patterns, showed network simulations of what congestion would look like, and calculated the business impact: productivity loss, support tickets for voice quality issues, etc. I presented this in a business context, not just technical jargon. Then I acknowledged his concern about cost and proposed an alternative: a second link with a lower-cost provider instead of our primary carrier. This wasn't free, but it was much cheaper than his original plan and solved the technical risk. He appreciated that I engaged with his concern rather than just opposing him. We implemented the solution, and it worked well.

136

Can you explain what a VLAN is and its purpose?

Reference answer

A VLAN (Virtual Local Area Network) is a logical grouping of devices within a single Ethernet network segment. It helps reduce the number of broadcast domains and network subnets, allowing multiple networks to share the same physical infrastructure without interference.

137

What is the primary purpose of TCP window scaling?

Reference answer

To increase the TCP window size beyond 65,535 bytes, allowing for higher throughput over high-latency or high-bandwidth networks.

138

What components would be required to setup IPSEC VPN connection between two offices?

Reference answer

Components required include: 1) Two VPN-capable routers or firewalls (one at each office) 2) Public IP addresses on both ends (static or dynamic with DDNS) 3) Pre-shared keys or digital certificates for authentication 4) IPSec configuration parameters (e.g., encryption algorithms, IKE policies) 5) Internet connectivity at both sites.

139

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.

140

Explain RF interference and mitigation strategies?

Reference answer

RF interference occurs when external devices or neighboring wireless networks disrupt Wi-Fi signals, leading to poor performance or connectivity issues. Common sources include nearby access points, microwave ovens, and Bluetooth devices. Mitigation strategies include: - Choosing non-overlapping channels. - Using 5 GHz for high-density areas. - Adjusting AP power levels to reduce interference.

141

What are the 6 key design considerations for satisfying business and RF requirements in Wi-Fi design?

Reference answer

The 6 key design considerations are: 1) Coverage, 2) Capacity, 3) Designing for the Least Capable, Most Important Device (LCMID), 4) Obstacles in the Physical Environment and Where to Install APs, 5) Wall Material and Attenuation Testing, and 6) RF Spectrum Activity.

142

What is 802.1x?

Reference answer

802.1x: IEEE standard for port-based network access control, providing an authentication framework for wireless LANs. It authenticates devices wishing to attach to a LAN or WLAN through a central authority.

143

What is the purpose of a MAC address?

Reference answer

A MAC (Media Access Control) address is a unique identifier assigned to network interfaces for communications on the physical network segment. It ensures that data packets reach the correct device within a local network. For example, a network switch uses MAC addresses to direct data to the appropriate device.

144

What is World Mode?

Reference answer

World Mode: Adjusts channel and power settings of client devices based on geographic location.

145

Do you have any experience managing WLAN security?

Reference answer

This question tests the candidate's knowledge of wireless LAN security practices, including encryption standards (e.g., WPA2/WPA3), authentication methods, and threat mitigation.

146

In a Corporate Head Office Network Setup, User LAN traffic is supposed to traverse through Firewall before talking to Application Servers. However, on verifying the traffic Flow (User LAN to App Server) flow via Firewall, no traffic is seen. What could be the reason for no traffic log in Firewall? What change needs to be performed to achieve the required traffic flow?

Reference answer

The reason could be that the default gateway of the User LAN or Application Server LAN is not pointing to the Firewall, causing traffic to bypass it. To achieve the required flow, change the default gateway on the User LAN VLAN interface to the Firewall's internal interface, and ensure routing on the Application Server LAN points back through the Firewall.

147

How do you perform a site survey for a large enterprise network?

Reference answer

Performing a site survey involves the following steps: - Identify areas requiring wireless coverage - Measure signal strength at multiple locations - Detect sources of interference - Place access points to achieve optimal coverage - Validate network performance using test clients - Document survey results to assist with future network expansion and optimization This structured approach ensures reliable performance and scalability in large enterprise environments.

148

What are the three main factors affecting wireless networks?

Reference answer

Reflection (signal bounces off materials like metal), Scattering (signal hits a surface and breaks apart, weakening it), and Absorption (materials like water and the human body absorb the signal).

149

Have you completed any certifications specific to wireless communication or networking systems?

Reference answer

Certifications indicate the professional's dedication towards learning and staying updated in their field. If they possess certifications like CCNA Wireless, CWNA, CCNP Wireless, then it's evident that they're trained in handling wireless communication and networking systems in a professional context.

150

While sizing a switch for LAN user termination, what should be oversubscription ratio?

Reference answer

For LAN user termination, the recommended oversubscription ratio is typically 20:1 to 50:1 for access switches. This means the aggregate bandwidth of user ports (e.g., 48 x 1G) can be up to 20-50 times the uplink bandwidth (e.g., 2 x 10G), balancing cost and performance.

151

Tell me about a time you designed a network solution that improved performance and reliability.

Reference answer

At Cisco, I worked on a project to redesign the network infrastructure for a client facing frequent downtime. My task was to create a more resilient design. I conducted a thorough analysis of the existing architecture, engaged with stakeholders to understand business needs, and designed a redundant network topology. The result was a 99.99% uptime over the next year, significantly enhancing client satisfaction.

152

What is a trunk port, and why is it important in networking?

Reference answer

A trunk port is configured to handle traffic from multiple VLANs by encapsulating the traffic with VLAN tags. This allows the simultaneous transmission of multiple VLANs over a single link between switches or network devices, optimizing the use of network resources.

153

What is the Least Capable, Most Important Device (LCMID) in Wi-Fi design?

Reference answer

The Least Capable, Most Important Device (LCMID) is the most critical device that is the least technologically advanced among the devices connecting to the network. Examples include a 10-year-old warehouse scanner used 12 hours per day, point-of-sale registers, or your CEO's laptop. You need to research the manufacturer's posted specifications to ensure they will perform reliably on the network.

154

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.

155

How would you handle a situation where a business requirement conflicts with technical best practices?

Reference answer

This happened when a department wanted to deploy a custom application that required direct internet access from specific servers, bypassing our standard security controls. My first instinct was ‘no,' but that's not a great answer in business. Instead, I sat down with the security team and the business stakeholders to understand what they were actually trying to accomplish. It turned out they needed internet connectivity for a third-party API integration. Rather than bypass our controls, I designed a solution: we created a DMZ segment with appropriate security controls, implemented explicit outbound rules for the specific endpoints they needed, and added monitoring and logging. This gave them the business capability they needed while maintaining security posture. The key was understanding the underlying business requirement rather than just saying no to the request.

156

Which of the multiplexing techniques are used to combine analog signals?

Reference answer

To combine analog signals, commonly FDM(Frequency division multiplexing) and WDM (Wavelength-division multiplexing) are used.

157

What is the primary purpose of TCP window scaling?

Reference answer

The primary purpose of TCP window scaling is to increase the TCP receive window size beyond 65,535 bytes, allowing for higher throughput and better performance over high-latency or high-bandwidth networks.

158

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

Reference answer

This question assesses the candidate's understanding of beamforming challenges, such as signal focusing, client compatibility, and interference management in multi-antenna systems.

159

How do you measure the success of a network architecture project after implementation?

Reference answer

I measure success by analyzing performance metrics and user feedback to ensure the network meets its intended goals. Comparing pre- and post-implementation benchmarks helps identify improvements, while assessing alignment with business objectives ensures the project delivers value.

160

How would you describe network topology?

Reference answer

These types of network engineer interview questions are designed to test your technical understanding to ensure you're suited to the network engineering role they're looking to fill. Keep your answer brief and to the point. Here's an appropriate response to give to an interviewer if they ask you this question. "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."

161

What is Kerberos?

Reference answer

Kerberos is a network security protocol initially developed by MIT (Massachusetts Institute of Technology) that is specifically utilized for authenticating service requests among multiple trusted hosts over an untrusted network, such as the Internet. It works via various crucial elements. These are: - Client: The individual attempting to establish a connection with a particular service. - Server: The server is responsible for hosting the service. - Authentication Server (AS): Verifies the identity of the user. Upon successful client authentication, a Ticket Granting Ticket (TGT) is generated as evidence of the client's authenticity. - Ticket Granting Server (TGS): A server application that generates and delivers service tickets. - Key Distribution Center (KDC): A server that hosts AS, database, and TGS.

162

What is the purpose of a wireless access point (AP)?

Reference answer

A wireless access point (AP) provides wireless connectivity to devices within a network. It acts as a bridge between wireless clients and the wired network, allowing devices to connect to the network without physical cables.

163

Which of the following best describes the structure and addressing types of IPv6?

Reference answer

IPv6 uses 128-bit addresses, represented in hexadecimal format (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334), and supports addressing types such as unicast, multicast, and anycast.

164

What are the key wireless design considerations for multi-floor and large enterprise buildings?

Reference answer

The key wireless design considerations for multi-floor buildings, APs are staggered vertically to avoid interference and maximize coverage. Controllers handle roaming, security, and authentication, while monitoring tools track client performance and optimize network configuration.

165

Describe a scenario in which you had to adjust your project management approach due to unforeseen circumstances in an RF Engineering context. How did you handle it?

Reference answer

Look for flexibility and problem-solving skills—key components in project management. The candidate should be able to provide a clear example of adaptability and decision-making under pressure.

166

What is a proxy server and what are its benefits?

Reference answer

A proxy server acts as an intermediary between a client (like your computer) and another server (like a website). When you make a request to a website, the request first goes to the proxy server. The proxy server then forwards the request to the destination server and, when the destination server responds, the proxy relays the response back to you. Benefits include: anonymity and privacy, content filtering, improved performance through caching, and bypassing geo-restrictions.

167

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.

168

What is MU-MIMO, and how does it enhance wireless performance?

Reference answer

MU-MIMO (Multi-User, Multiple Input, Multiple Output) allows a wireless access point to communicate with multiple devices simultaneously, rather than sequentially. This technology enhances performance by increasing the efficiency and speed of data transmission for multiple users.

169

When two laptops are directly connected wirelessly, what type of topology has been created?

Reference answer

An ad-hoc topology (IBSS) has been created.

170

Explain the term Jitter.

Reference answer

Jitter refers to a "packet delay variance," which is a problem when multiple packets of data encounter multiple delays in the network, and the data at the acceptor application is time-critical, i.e., audio or video data. It is calculated in milliseconds and is described as interference with the normal process of sharing data packets.

171

What is a firewall and why do we need it?

Reference answer

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and an untrusted external network, such as the internet. We need firewalls to protect our systems and data from unauthorized access, malicious attacks (like viruses and malware), and data breaches. They help prevent hackers from gaining access to sensitive information and disrupting our network operations. They inspect network traffic, blocking malicious packets and allowing legitimate communication based on the defined rules.

172

Do you have any experience with VoIP systems and technologies?

Reference answer

Voice over Internet Protocol has become an integral part of many businesses. Having someone who understands VoIP systems and technologies can be a significant advantage for any modern business.

173

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.

174

Describe a time when you received critical feedback about your work. How did you handle it?

Reference answer

A peer reviewed my network design and criticized it for being over-engineered. Instead of getting defensive, I listened. He was right—I'd designed redundancy and failover for scenarios that were unlikely in this organization's context. I'd been applying lessons from my previous role without fully adapting to the current organization's risk tolerance and budget. This feedback made me realize I needed to be better at understanding organizational context before designing. I actually asked him to mentor me a bit on their environment, and it completely changed how I approach design work here. Now I always start with understanding the specific business context, risk tolerance, and constraints rather than applying a generic ‘best practice' architecture. The designs I create now are actually better because they're tailored to the specific organization.

175

What is the difference between WPA and WPA2 encryption?

Reference answer

WPA uses RC4 encryption with TKIP (Temporal Key Integrity Protocol) for increased security over WEP, while WPA2 uses AES (Advanced Encryption Standard) which is more secure and completely redesigned.

176

What is network security and why is it important?

Reference answer

Network security involves measures and protocols designed to protect the integrity, confidentiality, and availability of data and resources on a network. It is important because it helps prevent unauthorized access, data breaches, and attacks that can disrupt network operations, compromise sensitive information, and damage an organization's reputation.

177

What is the difference between a vulnerability assessment and a penetration test?

Reference answer

A vulnerability assessment is a process of identifying and evaluating security vulnerabilities in a network or system. It provides a broad view of potential weaknesses but does not typically involve exploiting these vulnerabilities. A penetration test, on the other hand, involves simulating real-world attacks to actively exploit vulnerabilities and assess the effectiveness of security controls. Penetration testing provides a more in-depth evaluation by demonstrating how an attacker might exploit weaknesses to gain unauthorized access.

178

What difference between HLD and LLD?

Reference answer

HLD (High-Level Design) provides an overview of the network architecture, including topology, major components, and high-level traffic flows. LLD (Low-Level Design) provides detailed specifications, such as device configurations, IP addressing, VLAN assignments, and specific implementation steps. HLD is conceptual, while LLD is implementation-focused.

179

What is a Proxy Server?

Reference answer

A proxy server is a computer or system that works like a middleman between your device and the internet. It is used for better security, privacy, control, and faster access to some websites. If you want to open a website on your browser, you just type the address, and it will open the website. But when a proxy server is used, your request first goes to the proxy server, which then sends it to the website. Why do companies use a proxy server? There are many reasons for using a proxy server. Here are some important ones: - Security: A proxy server hides the real IP Address of users. It can help protect systems from hackers. - Control: Companies use it to block websites like games or social media during work hours. - Faster Browsing: Some proxy servers save copies of websites in memory. If the user reloads this website, the server will serve it faster. - Privacy: A proxy server can hide the real identity of the user by showing its own server.

180

What are the two main categories of DNS messages?

Reference answer

The two categories of DNS messages are queries and replies.

181

What is network jitter?

Reference answer

Network jitter refers to the variation in delay between data packets transmitted over a network. It can affect the quality of voice and video communication, leading to choppy audio or video playback.

182

What is Piggybacking in the context of Wi-Fi?

Reference answer

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

183

What happens when you type a website address (URL) into your browser and press Enter?

Reference answer

First, the browser parses the URL to determine the protocol (e.g., HTTP or HTTPS), domain name (e.g., example.com), and path (e.g., /index.html). The browser then performs a DNS lookup to find the IP address associated with the domain name. The browser establishes a connection to the server at that IP address, sending an HTTP request for the specified resource. The server processes the request and sends back an HTTP response containing the requested data (HTML, CSS, JavaScript, images, etc.), which the browser then renders to display the webpage. If the request is HTTPS, an SSL/TLS handshake occurs to establish a secure connection before the HTTP request is sent. Any redirects will be followed during this process, issuing additional requests as necessary until the browser receives a final response it can display.

184

25 common teacher interview questions, with role-based answers for new teachers, career changers, substitutes, assistants, and experienced switchers — plus the.

Reference answer

Customer service interview questions and answers with copy-and-adapt templates, weak-answer examples, and role-specific versions for retail, hospitality.

185

What is the frequency range of the 802.11g standard?

Reference answer

2.4GHz Frequency.

186

Explain the process of what happens when you type a website address into your browser and press Enter.

Reference answer

When you type a website address (like www.example.com) into your browser and press Enter, several things happen. First, the browser checks its cache and the operating system's DNS cache for the IP address associated with the domain name. If not found, it queries a DNS server (typically provided by your ISP) to resolve the domain name to an IP address. The browser then establishes a connection with the server at that IP address, usually via TCP. Once connected, the browser sends an HTTP request to the server, requesting the content of the specified page (e.g., /index.html). The server processes the request and sends back an HTTP response, which includes the requested content (HTML, CSS, JavaScript, images, etc.) and other information, such as the HTTP status code. The browser then renders the content, displaying the webpage to you. This rendering process involves parsing the HTML, applying the CSS styles, and executing any JavaScript code.

187

What is 10Base2?

Reference answer

10Base2 defines the data transfer rate, i.e., 10Mbps, where Base is the "Baseband" and T defines the cable type. The IEEE 802.3a standard defines 10Base2, which includes data transmission rates of 10Mbps and a maximum segment length of 185 meters through the utilization of RG-58 coaxial cable. The 10Base2 protocol is characterized by a physical bus topology and employs BNC connectors that are equipped with 50-ohm terminators at both ends of the cable. It is necessary to ground one of the physical ends of every segment.

188

How is Bash used in network automation?

Reference answer

Bash helps automate repetitive actions on Unix-based systems and simplifies tasks like configuring network interfaces, managing firewall rules, and performing routine maintenance.

189

How do you approach designing a network that can scale with future business growth?

Reference answer

In my previous role at AT&T, I always start by analyzing the current usage patterns and projected growth of the business. I use modular design principles to ensure that components can be easily upgraded or expanded. For instance, I designed a network for a growing tech startup that allowed for seamless integration of new services, which proved essential when they expanded operations internationally.

190

Explain the difference between HTTP, HTTPs, TCP, UDP and gRPC.

Reference answer

The provided text does not contain an answer for this question.

191

What is network virtualization, and what advantages does it offer organizations?

Reference answer

Network virtualization involves creating virtual network resources, like virtual switches and routers, to optimize and simplify network management. Benefits include reduced hardware costs, improved resource utilization, and enhanced flexibility. For example, virtual networks can be quickly reconfigured to meet changing business needs without physical hardware changes.

192

What is the difference between WLAN and WiMAX?

Reference answer

WLAN is used as a wireless local area network for providing connectivity between WLAN-compliant devices. WiMAX is used as a wide area network for providing access between various wireless devices. WLAN standards are evolving, including 11a, 11b, 11g, 11n, 11ac, 11ad, and more. WiMAX follows IEEE standards viz. 16d and 16e. Both use the OFDM modulation scheme.

193

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

Reference answer

The primary benefit of using VLANs is to logically divide a single physical network into multiple broadcast domains, which enhances security by isolating network traffic and improves performance by reducing broadcast traffic within each VLAN.

194

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.

195

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

196

Tell us a bit about you and your background

Reference answer

This question gives you the opportunity to tell your potential employer a bit about you, from your interests to how you got to where you are in your network engineering career, whether youâre a graduate or senior network engineer. Keep your answer concise without rambling off-topic, and remember itâs important to keep linking back to the role and any previous positions youâve had within the space that are relevant to the network engineer job youâre applying for.

197

How do you determine the appropriate subnet size?

Reference answer

Subnet size is determined based on the number of hosts required, using subnet masks and CIDR notation to allocate IP addresses efficiently while considering future growth.

198

What is QoS and why is it important in network design?

Reference answer

QoS (Quality of Service) is a set of techniques to manage network resources and ensure the performance of critical applications by prioritizing certain types of traffic. It is important for ensuring that time-sensitive data, like VoIP and video, receive the necessary bandwidth and low latency. For example, QoS can prioritize video conference traffic over regular web browsing.

199

What is a network topology?

Reference answer

Network topology refers to the physical or logical arrangement of network devices and connections. It describes how devices are connected and how data flows through the network. Common network topologies include bus, star, ring, mesh, and tree.

200

How do you handle conflicts or disagreements with stakeholders regarding network design decisions?

Reference answer

I handle conflicts by actively listening to stakeholder concerns and presenting data-driven arguments to support my design decisions. By seeking compromise and finding mutually beneficial solutions, I ensure that all parties are satisfied and the project progresses smoothly.

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