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1
Resposta de referência
Wireless network redundancy can be implemented by using multiple access points and wireless controllers, configuring load balancing, and employing failover mechanisms. This ensures continuous network availability and reliability in case of device failures.
2
Resposta de referência
The most viable and economical solution is to implement Quality of Service (QoS) policies on the WAN routers. QoS can prioritize business-critical and rich media traffic (e.g., VoIP, video conferencing) over less important traffic, ensuring minimal disruption during congestion without requiring additional bandwidth.
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3
Resposta de referência
To handle roaming issues between access points, ensure that APs have sufficient overlapping coverage to allow smooth handoff. Configure fast roaming standards such as 802.11k, 802.11v, and 802.11r to assist clients in making efficient roaming decisions. Additionally, verify that client devices support these protocols and check for misconfigured channels or improper AP power levels that could disrupt seamless roaming.
4
Resposta de referência
Each standard represents a generation of Wi-Fi technology. The main wireless standards are as follows: - 802.11a: 5 GHz, up to 54 Mbps, used in early enterprise networks. - 802.11b: 2.4 GHz, up to 11 Mbps, compatible with older devices. - 802.11g: 2.4 GHz, up to 54 Mbps, backward compatible with 802.11b. - 802.11n: Both bands, introduced MIMO (Multiple Input, Multiple Output), speeds up to 600 Mbps, suitable for offices. - 802.11ac: 5 GHz only, supports wider channels (80/160 MHz), speeds over 1 Gbps. - 802.11ax (Wi-Fi 6): Dual-band, designed for high-density environments, improved efficiency with OFDMA, MU-MIMO, and better battery life for clients.
5
Resposta de referência
A Network Architect approaches multi-cloud network design by leveraging cloud-agnostic solutions, centralized security and policy management, standardized connectivity like SD-WAN, and redundancy strategies to ensure seamless interoperability between cloud providers.
6
Resposta de referência
The three-way handshake is a process where the client sends a SYN packet, the server responds with a SYN-ACK packet, and the client sends an ACK packet to confirm the connection establishment.
7
Resposta de referência
- You can mix wireless equipments from different vendors, but the recommendation is that you should prefer only prescribed vendors, because most wireless networking hardware vendors support the 802.11 standard they can inter operate. However, we recommend verification as the standard is a fairly recent one, and does specify two different methods for wireless communications; Frequency Hopping (FH) and Direct Sequence Spread Spectrum (DSSS or DS), which are not interoperable. - When purchasing wireless networking hardware from separate vendors be sure to obtain guarantees from the vendors that the hardware will interoperate and follows the standards. - Within a short time we expect all new wireless cards, like ethernet cards, to become inexpensive, ubiquitous and totally interoperable. - Also of note is that the latest version of the standard defines 11mbps and 5.5mbps networking, with support for the older standard 1mbps and 2mbps speeds. This provides some compatibility with different or older equipment. Note that this new standard covers DS-type Networks, not FH types. - Software access points such as InterGate which uses the wireless interface of the host computer should have no compatibility issues with third party wireless hardware, as long as standards are followed. Typically wireless hardware is identified to the software as a network interface, and therefore can be used in the same way as any other network card. So you can choose them from different vendors but keeping these things in mind and then go ahead.
8
Resposta de referência
802.1x is Port-Based Network Access Control for authenticating users before network access. EAP (Extensible Authentication Protocol) is a transport protocol optimized for authentication, not the authentication method itself.
9
Resposta de referência
Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) monitor network traffic for suspicious activity. IDS identifies and alerts administrators to potential threats, while IPS takes immediate action to block or mitigate these threats.
10
Resposta de referência
This question tests the candidate's knowledge of Extensible Authentication Protocol (EAP) methods (e.g., EAP-TLS, PEAP, EAP-FAST) and their preferences based on security, deployment complexity, and use case.
11
Resposta de referência
802.1X requires clients to authenticate through a RADIUS server before accessing the network. It supports multiple authentication methods, including usernames/passwords and certificates. Enterprise environments often integrate 802.1X with Active Directory to manage users centrally.
12
Resposta de referência
TCP port 22 is commonly associated with the Secure Shell (SSH) protocol.
13
Resposta de referência
Two technologies to connect two offices in remote locations are: 1) MPLS (Multiprotocol Label Switching) VPN, which provides secure and scalable connectivity over a service provider network. 2) IPSec VPN, which uses encrypted tunnels over the public Internet to establish secure site-to-site connections.
14
Resposta de referência
I stay up-to-date with networking technologies through a combination of online resources, professional development, and community engagement. I regularly read industry publications and blogs such as the Network World, Packet Pushers, and vendor-specific blogs (e.g., Cisco, Juniper) to understand current trends, new product releases, and emerging technologies like SD-WAN, SASE, and cloud networking. Furthermore, I actively participate in online forums like Stack Overflow and Reddit's r/networking to learn from others' experiences and contribute my own knowledge. I also take advantage of online courses and certifications offered by platforms like Coursera, Udemy, and vendor-specific training programs to deepen my understanding of specific networking concepts and tools. Attending webinars and virtual conferences also helps me to keep abreast of the latest advancements in the field.
15
Resposta de referência
A wireless network ACL restricts or permits traffic based on predefined rules, enhancing security by controlling access to network resources. It can be used to block unauthorized devices or limit access to specific services or applications.
16
Resposta de referência
DHCP (Dynamic Host Configuration Protocol) is a service that automatically assigns IP addresses to devices on a network. Instead of manually configuring IP settings, DHCP ensures that every device gets a unique IP address and necessary settings like subnet mask, default gateway, and DNS servers. When a device connects to a network, it sends a request, and the DHCP server assigns an available IP address.
17
Resposta de referência
Network segmentation divides a network into smaller subnetworks to improve performance, enhance security by limiting broadcast domains, and contain potential threats.
18
Resposta de referência
Look for an understanding of project success metrics specific to RF Engineering, like signal integrity, system efficiency, quality of service, and adherence to timelines and budgets.
19
Resposta de referência
WPA2 uses AES (Advanced Encryption Standard) for encryption and provides strong security for wireless networks. WPA3 improves on WPA2 by offering enhanced protection against brute-force attacks, improved encryption, and more robust authentication methods.
20
Resposta de referência
A network analyzer is a tool used to diagnose network performance and troubleshoot problems. It can analyze network traffic, identify bottlenecks, and provide insights into network performance metrics. Network analyzers can be used to identify slowdowns, packet loss, and other network issues.
21
Resposta de referência
The proxy server should be deployed in the DMZ (Demilitarized Zone) or at the network edge between the corporate LAN and the Internet firewall. This placement allows the proxy to inspect and filter outbound traffic, cache content, and enforce security policies while protecting internal users from direct exposure to the Internet.
22
Resposta de referência
High availability requires implementing redundancy and failover mechanisms. For this, they'd need to: Use multiple, redundant links and devices to eliminate single points of failure; Implement technologies like load balancing and clustering to distribute traffic evenly and handle failures; Make regular backups and have disaster recovery plans to restore services quickly.
23
Resposta de referência
PMK caching stores session keys on the AP or client, allowing faster authentication when a client roams between access points. By avoiding a full EAP (Extensible Authentication Protocol) handshake during each roam, it reduces latency and improves the overall roaming performance in enterprise wireless networks.
24
Resposta de referência
WEP and WPA (version 1) are based on the RC4 encryption algorithm.
25
Resposta de referência
The candidate should highlight real-world challenges they've faced, such as signal degradation, unwanted capacitance, or transmission line issues at higher frequencies. They should mention how they overcame these problems, like adjusting impedance matching, using specialized materials, or redesigning parts of the system to handle high-frequency signals effectively.
26
Resposta de referência
Implementation involves: 1) Configuring a public IP address for web hosting on the firewall or router with NAT for inbound traffic. 2) Setting up a cloud proxy (e.g., Cloudflare or AWS CloudFront) to handle web traffic, with DNS pointing to the proxy. 3) Routing outbound traffic from the LAN through the proxy for security and caching, using PAC files or proxy configuration on clients.
27
Resposta de referência
To troubleshoot poor Wi-Fi coverage, check for physical obstructions or materials that block signals and verify AP placement and signal strength. Scan for interference from neighboring networks or devices, adjust AP power and channel allocation, and consider adding additional APs or using directional antennas to improve coverage.
28
Resposta de referência
This question assesses the candidate's familiarity with Single Sign-On (SSO) implementations in wireless networks, including integration with authentication protocols like RADIUS or LDAP.
29
Resposta de referência
The network 192.168.32.0/28 has a subnet mask of 255.255.255.240, providing 16 total addresses. Subtracting the network address (192.168.32.0) and broadcast address (192.168.32.15), the number of usable host addresses is 14.
30
Resposta de referência
A DHCP (Dynamic Host Configuration Protocol) server assigns IP addresses and other network configuration parameters to wireless devices automatically. It simplifies network management and ensures devices receive valid IP addresses for connectivity.
31
Resposta de referência
Wi-Fi vs Bluetooth: Wi-Fi is for high-speed internet access; Bluetooth is for short-range communication between devices.
32
Resposta de referência
Network segmentation divides a network into smaller, isolated segments, often based on function, risk level, or compliance requirements. This limits the blast radius of a security breach. Micro-segmentation takes this further, isolating individual workloads or applications, creating even more granular security boundaries. Think of network segmentation as dividing a house into rooms, and micro-segmentation as putting locks on each cabinet in those rooms. The benefits of both include reduced attack surface, improved threat containment (preventing lateral movement), enhanced compliance by isolating sensitive data, and simplified security management by applying targeted policies to specific segments. Micro-segmentation offers more precise control and visibility, making it easier to detect and respond to threats targeting specific applications or services.
33
Resposta de referência
The three-way handshake process used in TCP to establish a connection involves: 1) The client sends a SYN packet to the server. 2) The server responds with a SYN-ACK packet. 3) The client sends an ACK packet to confirm the connection.
34
Resposta de referência
FIN, ACK, FIN, ACK (or FIN from one side, ACK, then FIN from the other side, ACK).
35
Resposta de referência
TCP (Transmission Control Protocol) is connection-oriented and ensures reliable data transfer with error checking and retransmission. UDP (User Datagram Protocol) is connectionless and faster but does not guarantee delivery, making it suitable for applications like streaming where speed is more critical than reliability. For example, TCP is used for web browsing, while UDP is used for live video streaming.
36
Resposta de referência
Sure, let's start with circuit switching. This is an older technology mostly used for telephone communications. In circuit switching, a dedicated physical path is established between the sender and receiver before they can communicate. This path, or 'circuit,' remains open for the duration of the communication, guaranteeing a constant data rate and delay. However, the circuit can't be used by other callers until the call is finished, which can be inefficient. Now, packet switching, which is used in most modern networks, including the internet, operates quite differently. Instead of establishing a dedicated path, data is broken down into small chunks called 'packets'. Each of these packets contains metadata on where it came from and where it's going. The packets get sent over the network by the best available route, which may not be the same for all packets. Once they all arrive, the data is reassembled in the correct order. This technique allows for better use of network resources by allowing multiple users to send and receive packets over the same lines. So the main difference is that circuit switching establishes a direct, dedicated path for communication, while packet switching divides data into packets and sends them over the network independently. Packet switching is generally seen as the more efficient of the two, ideal for today's high-speed, high-traffic networks.
37
Resposta de referência
A MAC (Media Access Control) address is a unique identifier assigned to a network interface controller (NIC) for communication within a network segment. It's like a physical address burned into the hardware. Its primary purpose is to enable communication between devices on the same local network. An IP (Internet Protocol) address, on the other hand, is a logical address used to identify a device on an IP network, enabling communication across different networks, including the internet. The key difference lies in their scope and function. MAC addresses handle local network communication (layer 2 in the OSI model), while IP addresses handle communication across networks (layer 3). MAC addresses are permanent and hardware-specific, while IP addresses can be dynamically assigned and change depending on the network the device is connected to. Think of MAC as identifying you in your apartment building and IP as identifying your apartment building in the world.
38
Resposta de referência
Network protocols are rules that define how data is transmitted and received between devices. Some common ones include: - HTTP/HTTPS: Used for web browsing; HTTPS is the secure version with encryption. - FTP (File Transfer Protocol): Transfers files between devices over a network. - TCP/IP: Ensures reliable communication between devices on the internet. - DNS (Domain Name System): Translates domain names (e.g., google.com) into IP addresses. - SMTP/IMAP/POP3: Used for sending and receiving emails.
39
Resposta de referência
Two-factor authentication (2FA) is a security process that requires users to provide two different types of identification before accessing an account or system. It typically involves something the user knows (like a password) and something the user has (like a smartphone for a verification code). 2FA enhances security by adding a layer of verification, making it more difficult for unauthorized users to gain access.
40
Resposta de referência
Reflection (signal bounces off materials like metal), Scattering (signal hits a surface and breaks apart, weakening the signal), and Absorption (material like water or the human body absorbs the signal, leaving little left).
41
Resposta de referência
The OSI (Open Systems Interconnection) model is a seven-layer framework that standardizes the functions of a network into layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. Each layer has specific roles and responsibilities in the communication process. - Which layer is the Application Layer, and what is its function? The Application Layer is the topmost layer, providing network services directly to applications. It handles protocols and data that applications use to communicate over the network. - Which layers are considered the hardware or network support layers? The Data Link Layer and Physical Layer are considered hardware or network support layers. They deal with the physical transmission of data and error detection/correction.
42
Resposta de referência
Carrier aggregation is a technique in LTE that combines multiple frequency bands to increase the total available bandwidth and thus improve data rates. It enhances user experience by providing faster downloads and more capacity for data services.
43
Resposta de referência
Experience with next-gen protocols like Wi-Fi 6 gives an impression of their extensive knowledge on latest wireless standards and their readiness to evolve with changing technology trends.
44
Resposta de referência
Microwave ovens and cordless phones (operating on 2.4GHz frequency).
45
Resposta de referência
5GHz Frequency.
46
Resposta de referência
Network latency refers to the delay or time it takes for data to travel from one point on a network to another. It's typically measured in milliseconds (ms) and represents the round-trip time for a small packet of data. High latency means a longer delay, while low latency means a shorter delay. Several factors can contribute to network latency, including distance, network congestion, and the number of hops between sender and receiver. Latency is important because it directly impacts the user experience in various applications. High latency can cause slow loading times for websites, lag in online games, buffering in video streaming, and delays in real-time communication. Reducing latency is crucial for ensuring responsiveness and a smooth user experience, especially for applications requiring real-time interaction or time-sensitive data.
47
Resposta de referência
An 802.1X authentication server (often a RADIUS server) provides centralized authentication for wireless clients. It verifies user credentials and grants access based on policies, enhancing network security and access control.
48
Resposta de referência
IPv4 and IPv6 are different versions of the Internet Protocol, used for addressing and identifying devices on a network. IPv4 uses a 32-bit address (e.g., 192.168.1.1), allowing for approximately 4.3 billion unique addresses. IPv6 uses a 128-bit address (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334), providing a vastly larger address space (2128 addresses), essentially solving the IPv4 address exhaustion problem. IPv6 also incorporates improvements like stateless address autoconfiguration and enhanced security features compared to IPv4. The headers differ as well, IPv6 has a simplified header making it more efficient.
49
Resposta de referência
Common network security protocols include: - SSL/TLS: Encrypts communication between web browsers and servers, ensuring secure data transfer. - IPsec: Provides secure communication between networks or devices, encrypting data and verifying authenticity. - WPA2/WPA3: Secure wireless communication protocols for Wi-Fi networks. - SSH: Provides secure remote access to devices and networks, encrypting communication between clients and servers.
50
Resposta de referência
Ensuring compliance involves: ● Understanding Requirements: Familiarize yourself with relevant regulations (e.g., GDPR, HIPAA) and industry standards (e.g., ISO 27001). ● Policy Development: Develop and implement security policies that align with regulatory requirements and best practices. ● Regular Audits: Conduct internal and external audits to verify compliance with security policies and regulations. ● Training and Awareness: Provide regular training for employees on security policies, procedures, and compliance requirements. ● Documentation: Maintain thorough documentation of security practices, policies, and compliance efforts.
51
Resposta de referência
Staying current with trends is crucial in network security. Some of the latest trends and technologies include: ● Zero Trust Security: A model that assumes no entity, whether inside or outside the network, should be trusted by default. ● Artificial Intelligence and Machine Learning: Enhancing threat detection and response through advanced algorithms and automated analysis. ● Extended Detection and Response (XDR): Integrating multiple security solutions to provide a unified approach to threat detection and response. ● Security Automation: Automating routine security tasks to improve efficiency and response times.
52
Resposta de referência
Ad-hoc topology (IBSS - Independent Basic Service Set).
53
Resposta de referência
Cisco Enterprise Wireless Architecture includes APs, WLCs, and management tools. APs provide the wireless signal, while WLCs centrally manage multiple APs, handle client roaming, apply security policies, and maintain network stability. Controllers also collect statistics about network performance and allow IT teams to configure updates centrally. Mobility controllers enable seamless handoff when users move across different APs without losing connection. Management tools provide visibility into network health, client behavior, and potential issues.
54
Resposta de referência
Ensuring compliance with network security policies and regulations involves a multi-faceted approach. Key aspects include: implementing and enforcing security policies (e.g., access control lists, firewall rules), conducting regular security audits and vulnerability assessments, using monitoring tools to track network activity and detect anomalies, maintaining detailed documentation of network configurations and changes, providing security awareness training to users, and staying informed about relevant regulations (e.g., GDPR, HIPAA, PCI-DSS). Effective compliance requires continuous monitoring, evaluation, and adaptation to the evolving threat landscape and regulatory requirements. Automation wherever possible improves efficiency and reduces error.
55
Resposta de referência
The recommended configuration on Cisco routers is to use HSRP (Hot Standby Router Protocol) or VRRP (Virtual Router Redundancy Protocol) for gateway redundancy, combined with static or dynamic routing to prefer the active link. For example, configure HSRP on the LAN-facing interfaces and set a higher metric on the standby link's default route to ensure failover.
56
Resposta de referência
A forward proxy and a reverse proxy both work as a middleman in a network, but their differences lie in who they protect and where they are placed in a network. | Forward Proxy | Reverse Proxy | | It works for users/clients. | It mainly works for servers. | | It sits in front of users. | It sits in front of the servers. | | It is used to hide the client's identity. | It is used to hide the server's identity. | | Used inside organizations | Used in data centers and websites | | It primarily controls the user's internet access. | It primarily controls incoming user requests. |
57
Resposta de referência
Managers ask this to gauge your hands-on experience optimizing WLANs in challenging scenarios. They want to see that you can apply a multi-faceted approach. Successful candidates for a wireless network engineer job outline these essential strategies: Channel allocation and power management Client load balancing across access points Band steering implementation QoS policy configuration Interference mitigation techniques
58
Resposta de referência
Staying updated involves continuous learning through industry certifications, attending conferences, participating in webinars, reading technical blogs and journals, and joining professional networking groups. For example, I follow networking forums and subscribe to newsletters from leading tech companies like Cisco and Juniper.
59
Resposta de referência
NAT is a technique used by routers to translate private IP addresses used within a network into public IP addresses for communication with external networks. It helps conserve public IP address space and enhances network security.
60
Resposta de referência
Network Address Translation (NAT) is a technique used to remap one IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. A common use case is to enable multiple devices on a private network to share a single public IP address when communicating with the internet. NAT can impact network security in several ways. On one hand, it provides a degree of security by hiding the internal network structure and IP addresses from the outside world, making it harder for attackers to directly target internal devices. On the other hand, NAT can complicate certain security protocols, such as IPSec, and can make it more difficult to trace malicious activity back to the originating internal device. Additionally, applications that rely on end-to-end connectivity may not function correctly behind NAT without specific configurations like port forwarding. Some also consider NAT to be security through obscurity which is generally not an effective security strategy.
61
Resposta de referência
When designing a data center network, skilled network engineers would focus on factors like scalability, redundancy, and security, to ensure the network can handle increasing data loads and expand as needed. They'd also implement redundant paths and devices to maintain availability and reliability and consider implementing strong security measures, including firewalls, intrusion detection systems, and secure access controls.
62
Resposta de referência
This question tests the candidate's awareness of typical configuration errors, such as improper channel selection, security misconfigurations, or inadequate site surveys.
63
Resposta de referência
Managing a multi-vendor environment requires a well-structured approach to ensure interoperability, performance, and security. My approach includes: - Standardization: Using industry-standard protocols (e.g., BGP, OSPF, SNMP) to ensure seamless integration between vendors. - Testing & Validation: Conducting rigorous lab testing before deploying solutions into the production network. - Automation & Orchestration: Leveraging tools like Ansible and Terraform to maintain consistency in configurations. - Vendor Collaboration: Maintaining strong relationships with vendors for support and timely updates. - Monitoring & Troubleshooting: Implementing multi-vendor network monitoring tools to proactively detect and resolve issues.
64
Resposta de referência
A network security audit is a systematic evaluation of network security controls and practices to identify vulnerabilities, weaknesses, and non-compliance with security policies. It aims to assess the overall security posture of the network and identify areas for improvement.
65
Resposta de referência
Channel planning involves selecting and configuring wireless channels to minimize interference and optimize network performance. Proper planning ensures that adjacent access points use non-overlapping channels to avoid co-channel interference.
66
Resposta de referência
EAP (Extensible Authentication Protocol): Used in wireless communications for user authentication through an Access Point and an authentication server.
67
Resposta de referência
- To do this you will need some sort of bridge between the wireless and wired network. This can be accomplished either with a hardware access point or a software access point. Hardware access points are available with various types of network interfaces, such as Ethernet or Token Ring, but typically require extra hardware to be purchased if your networking requirements change. - If networking requirements go beyond just interconnecting a wired network network to a small wireless network, a software access point may be the best solution. - A software access point does not limit the type or number of network interfaces you use. It may also allow considerable flexibility in providing access to different network types, such as different types of Ethernet, Wireless and Token Ring networks. Such connections are only limited by the number of slots or interfaces in the computer used for this task. - Further to this the software access point may include significant additional features such as shared Internet access, web caching or content filtering, providing significant benefits to users and administrators.
68
Resposta de referência
This question probes the candidate's practical experience in designing wireless LANs, including planning for coverage, capacity, and user density, and asks for a specific success story.
69
Resposta de referência
The candidate is expected to provide insight into the integration and coexistence of 5G with legacy protocols, the adjustments needed in RF design, and the overall evolution of wireless communication systems.
70
Resposta de referência
1) The first line of defense of your Wi-Fi network is encryption, which encodes the data transmitted between your PC and your wireless router. 2) WEP abbreviates (Wireless Encryption Protocol). It is a less-secure protocol than WPA (Wireless Protected Access). Since WEP is relatively easy to crack, so you have to use the same form on all devices on your network. If you have an older router that supports WEP only you'll be best safest if you use 128-bit bit WEP keys but also check the manufacturer's Web site for a firmware update that will add WPA support. 3) Two of the most popular programs used for actually cracking the WEP key are Airsnort and Aircrack. Airsnort can be used with the .dump files that Kismet provides; and Aircrack can be use with .cap files that Airodump provides.
71
Resposta de referência
Network redundancy involves creating multiple paths for data transmission, ensuring continued network operation even if one path fails. This improves reliability and availability. Examples include: - Redundant routers: Multiple routers are configured to provide backup paths. - Redundant links: Multiple connections between devices, allowing data to flow through alternative routes. - Redundant power supplies: Backup power sources ensure network operation in the event of a power outage.
72
Resposta de referência
Anycast address is a single IP address utilized by a set of servers at different sites. When one directs any request to an Anycast address, the address is redirected to the nearest server. This will improve the speed and consistency of network services since the distance the information needs to travel is reduced. It is also able to help manage heavy traffic at the same time. How it works: - The same IP address is used for many servers. - The network finds the closest server to you. - Your request is sent to that server automatically. - If one server fails, traffic is redirected to the next closest server.
73
Resposta de referência
TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both protocols used for sending data over the internet, but they differ in their approach. TCP is connection-oriented, meaning it establishes a connection before sending data, ensures reliable delivery using acknowledgements and retransmissions, and provides ordered delivery. UDP, on the other hand, is connectionless; it sends data without establishing a connection first, offering faster transmission speeds but without guaranteed delivery or order. In summary, TCP is reliable but slower, suitable for applications like web browsing and file transfer where data integrity is paramount. UDP is faster but unreliable, making it suitable for applications like streaming and online gaming where speed is more important than perfect data delivery.
74
Resposta de referência
In the OSI model, transmission media supports layer-1(Physical layer).
75
Resposta de referência
Wired networks are connected to each other using wires, while wireless networks do not use cables but use radio waves to transmit data.
76
Resposta de referência
Orthogonal Frequency Division Multiplexing (OFDM): It is also the multiplexing technique that is used in an analog system. In OFDM, the Guard band is not required and the spectral efficiency of OFDM is high which oppose to the FDM. In OFDM, a Single data source attaches all the sub-channels.
77
Resposta de referência
A hub operates at the physical layer (Layer 1) of the OSI model and simply rebroadcasts any received data to all connected devices. This creates a collision domain, meaning only one device can transmit at a time without causing data collisions. A switch, on the other hand, operates at the data link layer (Layer 2) and uses MAC addresses to forward data only to the intended recipient. This creates separate collision domains for each port, allowing multiple devices to transmit simultaneously without collisions, resulting in improved network performance and security.
78
Resposta de referência
The recommended approach for Riverbed Steelhead (WAN optimization) placement is to install it in-path between the router and the LAN switch. This allows the Steelhead to intercept and optimize traffic traversing the WAN link without requiring changes to the router configuration, ensuring transparent optimization.
79
Resposta de referência
The maximum data rate for 802.11a is up to 54 Mbit.
80
Resposta de referência
I use a mix of technical and business metrics. Technically, I track availability (we target 99.99% uptime), latency for critical applications, and bandwidth utilization to ensure we're not overprovisioned. But I also track business-aligned metrics: mean time to recovery when incidents occur, time to deploy new applications and services, and infrastructure costs per user or per transaction. I also track something I call ‘security incident velocity'—how quickly we can detect and respond to security events. These metrics help me have conversations with business leaders in their language. For example, when I proposed a cloud integration initiative, I showed it would reduce time-to-market for new features from 8 weeks to 3 weeks, which the CEO understood would make us more competitive. I also measure team satisfaction—if my architecture is causing constant firefighting and frustration, that's a sign the design isn't working well operationally.
81
Resposta de referência
Load balancing distributes network traffic across multiple servers to prevent any single server from becoming overloaded. This is crucial for improving both performance and availability. By distributing the workload, load balancing ensures that users experience faster response times and reduced latency, as requests are handled by servers with available resources. Its role is vital for high availability. If one server fails, the load balancer automatically redirects traffic to the remaining healthy servers, minimizing downtime and ensuring continuous service availability. This also allows for easier scaling, as new servers can be added to the pool without disrupting service. Common algorithms are round robin, least connections, and IP hash.
82
Resposta de referência
Beacon, Directed Probe request, Probe Response, Assoc Req, Re-association Req
83
Resposta de referência
This question evaluates the candidate's understanding of RF propagation principles, such as path loss, fading, and interference sources, and their ability to manage these factors in network design.
84
Resposta de referência
802.1X is port-based network access control where users must authenticate themselves before getting any network access, even before receiving an IP address from DHCP.
85
Resposta de referência
The Shannon-Hartley theorem defines the maximum data rate (capacity) of a communication channel based on its bandwidth and SNR. It provides a theoretical limit on how much information can be transmitted error-free over a given channel.
86
Resposta de referência
DNS stands for Domain Name Server. It translates Internet domains and hostnames to IP addresses and vice versa. DNS technology allows typing names into your Web browsers and your computer to automatically find that address on the Internet. A key element of the DNS is a worldwide collection of DNS servers. It has the responsibility of assigning domain names and mapping those names to Internet resources by designating an authoritativename server for each domain. The Internet maintains two main namespaces like Domain Name hierarchy and Internet protocol address space.
87
Resposta de referência
In infrastructure mode, devices connect through an access point or wireless router, which manages the network. In ad-hoc mode, devices connect directly to each other without an access point, suitable for small, temporary networks.
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At Singtel, I led a project to redesign the core network infrastructure to support a 50% increase in traffic. The major challenge was ensuring minimal downtime. I implemented a phased rollout strategy, allowing for thorough testing of each segment. The result was a seamless transition that improved network performance by 35% and reduced latency by 20%. This experience taught me the importance of proactive communication with stakeholders.
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Network Address Translation, or NAT, is a method used in networking to conserve public IP addresses and increase security. It manipulates IP addresses in the IP packet headers, allowing a single device, such as a router, to act as an agent between the Internet and a local network, which means that only a single unique IP address is required to represent an entire group of computers to anything outside their network. When computers on the local network transmit data to the internet, NAT modifies the source IP in the outgoing packet header to its own public IP address. Conversely, when data arrives from the internet, NAT converts the destination IP back to the relevant private IP address of the local computer. This is crucial because the number of available IPv4 addresses is less than the amount required for every individual device worldwide to have its own unique public IP. NAT mitigates this by allowing many devices with private IPs on a local network to share a single public IP for communicating over the internet. Importantly, it also enhances security because it essentially hides the IP addresses of individual devices on a local network, making them less susceptible to direct attacks.
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I have experience with implementing and managing both signature-based and anomaly-based IDS/IPS solutions, primarily using Snort and Suricata on Linux-based systems. My responsibilities included installing, configuring, and fine-tuning these systems to detect and prevent malicious network activity. This involved creating and customizing rule sets to identify specific attack signatures, as well as establishing baselines for normal network behavior to detect anomalies. Specifically, I worked on integrating these systems with SIEM solutions like Splunk for centralized log management and analysis. I also performed regular updates to the rule sets and software to ensure they were effective against the latest threats. A key part of my role was analyzing alerts, distinguishing between false positives and genuine threats, and taking appropriate remediation steps, such as blocking malicious IP addresses or isolating infected systems. In one instance, I used Snort rules to identify and block a series of SQL injection attempts against a web server, preventing a potential data breach.
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Resposta de referência
The Link Aggregation Control Protocol (LACP) combines multiple physical links into a single logical link, increasing bandwidth, providing redundancy, and balancing the traffic load across all available connections. This improves overall network performance, providing higher data transfer rates and robust fault tolerance, which is key for high-demand environments like data centers and enterprise networks.
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An IP or Internet Protocol address is a distinctive identifier allocated to every device on a network, enabling devices to find and interact with one another. For instance, 192.168.1.1 is a typical IP address assigned to home routers.
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To improve Wi-Fi performance in a high-density classroom: - Deploy multiple APs with overlapping coverage using the 5 GHz band - Enable load balancing to distribute clients evenly across APs - Conduct an RF survey to identify and avoid interference - Enable QoS to prioritize latency-sensitive applications like video streaming or VoIP
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A network bridge, as the name implies, is a device used to connect and "bridge" together different segments of a network. It operates at the data link layer (Layer 2) of the OSI model and can forward traffic between different sections of a network based on the MAC addresses of connected devices. When a data frame comes into the bridge, it reads the MAC address of the sender and adds it to a database of addresses and their associated network segments. When the bridge later receives a frame intended for that MAC address, it knows which segment to send the frame to. The main function of a bridge is to reduce network traffic on a LAN by dividing it into separate segments. It does this by only forwarding traffic to the segment where the intended recipient resides, rather than broadcasting the data across all segments of the network. This results in less congestion and improved overall network performance, particularly in environments with a lot of network traffic.
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Three basic parameters are SSID (network name), security settings (like encryption type), and channel selection.
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TCP (Transmission Control Protocol) provides reliable, ordered, and error-checked delivery of data and ensures data packets arrive intact and in sequence. UDP (User Datagram Protocol) is simpler and faster but does not guarantee delivery, order, or error-checking. Because of that, TCP is suitable for applications requiring reliability, like web browsing and email, while UDP is best for applications needing speed, like streaming and online gaming.
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The TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of communication protocols that are used to connect network devices on the Internet. The TCP/IP model has 4 layers, unlike the 7 layers of the OSI model. - Network Interface Layer - Internet Layer - Transport Layer - Application Layer The key difference is that TCP/IP is the actual protocol suite used in the real world, while the OSI model serves as a conceptual guideline.
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An issue that can cause the entire network to flap is a Layer 2 loop. It can be caused by improper cabling or Spanning Tree issues. Some symptoms of this issue are: - Flapping of MAC Address - High broadcast traffic - The network will be very slow - CPU spikes on switches To troubleshoot the issue, you can: - Check the status of STP - Find the links that can be reduced - Verify BPDU exchange - And disconnect suspected loop links The commands you need: "show spanning-tree" "show mac address-table"
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We discovered a significant security vulnerability in our network infrastructure that would require a costly and disruptive remediation process. I had to tell the VP of Operations that we'd need significant downtime to fix it. I prepared thoroughly—I gathered all the details about the vulnerability, the risk it posed, and the specific steps required to fix it. Rather than just delivering bad news, I came with options: Option A was immediate remediation with acceptable downtime windows; Option B was phased remediation that spread the work over several months with less downtime per window but keeping us at some risk longer. I also explained what the business impact would be if we did nothing and the vulnerability was exploited. He appreciated that I didn't sugarcoat the problem or hide behind technical jargon. We chose Option A because the risk was too high. I managed the implementation carefully to minimize business impact, and we resolved the vulnerability with fewer incidents than we'd anticipated.