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Question 16:
Which protocol is used to propagate VLAN information across multiple switches in an enterprise network?
A) VTP
B) STP
C) HSRP
D) OSPF
Answer:
A) VTP
Explanation:
VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol used to manage and propagate VLAN configurations across multiple switches in an enterprise network. It provides a centralized mechanism for VLAN administration, ensuring consistency and reducing the chances of configuration errors. In large enterprise environments where hundreds of VLANs may exist, manual configuration of VLANs on every switch would be inefficient, prone to mistakes, and difficult to maintain. VTP simplifies this process by allowing VLAN information to be shared between switches through trunk links, which carry VLAN data along with normal traffic.
VTP operates in different modes: server, client, and transparent. In server mode, switches can create, delete, or modify VLANs, and these changes are propagated throughout the VTP domain. Client mode switches receive updates but cannot make modifications. Transparent mode switches do not participate in VTP propagation but can forward VTP advertisements across trunks. By carefully designing the VTP domain, enterprises can maintain consistent VLAN configurations across a campus or enterprise network, simplifying management and reducing errors that can lead to connectivity problems or security risks.
VTP also maintains a configuration revision number, which allows switches to identify the most recent VLAN information and update accordingly. Administrators must be cautious with revision numbers, as incorrect updates can overwrite existing VLAN configurations, causing network disruptions. VTP provides scalability in enterprise networks by reducing manual configuration overhead and ensuring that all switches have a synchronized VLAN database.
Other protocols listed serve different functions. STP (Spanning Tree Protocol) prevents Layer 2 loops but does not manage VLANs. HSRP provides gateway redundancy for hosts but does not propagate VLAN information. OSPF is a Layer 3 routing protocol that handles IP routing between networks but is unrelated to VLAN propagation.
In modern enterprise networks, understanding VTP is essential for designing scalable, manageable Layer 2 topologies. Candidates for the Cisco 350-401 ENCOR exam must understand VTP operation modes, domain design, versioning, and potential pitfalls. Proper VTP implementation ensures network consistency, reduces configuration errors, and supports dynamic VLAN management across large campus or enterprise environments, which is critical for operational efficiency and network reliability.
Question 17:
Which protocol provides loop-free Layer 2 topologies in a switched network?
A) STP
B) NAT
C) HSRP
D) DHCP
Answer:
A) STP
Explanation:
Spanning Tree Protocol (STP) is a Layer 2 protocol used to prevent switching loops in Ethernet networks. In enterprise networks, redundancy is often necessary to ensure high availability. Multiple physical paths are deployed between switches to avoid single points of failure. While these redundant paths improve fault tolerance, they also introduce the risk of loops, where Ethernet frames circulate indefinitely. STP addresses this by creating a loop-free logical topology and selectively blocking redundant paths.
STP elects a root bridge, which serves as the reference point for all path calculations. Switches determine the shortest path to the root bridge and place all non-optimal paths into a blocking state. This ensures that only one active path exists between any two switches while maintaining network connectivity. If the active path fails, STP recalculates the topology and unblocks an alternate path, maintaining connectivity.
Rapid Spanning Tree Protocol (RSTP) improves upon STP by providing faster convergence. Whereas traditional STP can take 30–50 seconds to respond to topology changes, RSTP typically converges in a few seconds, reducing downtime and improving network performance. Enterprise networks may also implement MSTP (Multiple Spanning Tree Protocol) to map multiple VLANs into separate spanning tree instances, optimizing bandwidth utilization while preventing loops.
Other protocols in the options perform different roles. NAT translates IP addresses for connectivity between networks but does not prevent Layer 2 loops. HSRP provides default gateway redundancy but does not manage Layer 2 topologies. DHCP dynamically assigns IP addresses but does not influence Layer 2 loop prevention.
Enterprise network engineers must understand STP operation, including root bridge election, port roles (root, designated, blocked), and port states (listening, learning, forwarding, blocking). Proper STP configuration prevents broadcast storms, MAC address instability, and network downtime. It also forms the foundation for designing reliable, redundant Layer 2 networks. For the Cisco 350-401 ENCOR exam, candidates must be proficient in STP concepts, RSTP enhancements, and MSTP configurations to design fault-tolerant and loop-free enterprise networks.
Question 18:
Which protocol allows devices in the same subnet to resolve the MAC address corresponding to an IP address?
A) ARP
B) DNS
C) ICMP
D) HSRP
Answer:
A) ARP
Explanation:
The Address Resolution Protocol (ARP) is a key protocol in enterprise networks that maps IP addresses to MAC addresses. When a device wants to communicate with another device on the same subnet, it must know the MAC address of the destination device to deliver Ethernet frames. ARP provides this mapping by broadcasting a request, asking which device owns the specified IP address. The device with the matching IP responds with its MAC address, allowing the sender to encapsulate data in an Ethernet frame for delivery.
ARP operates at the intersection of Layer 2 and Layer 3, bridging IP addressing and physical network delivery. It is essential for all IPv4 communication in Ethernet networks. Devices maintain an ARP table to cache recently resolved MAC addresses, improving efficiency and reducing unnecessary broadcast traffic. ARP also plays a critical role in network troubleshooting. Engineers use commands like “show arp” to verify MAC-to-IP mappings, detect duplicate addresses, and troubleshoot connectivity issues.
Other options serve different functions. DNS translates domain names into IP addresses but does not resolve MAC addresses. ICMP provides network diagnostics and error messages but does not perform address resolution. HSRP provides default gateway redundancy but does not resolve MAC addresses for devices in the subnet.
In enterprise environments, ARP security is important to prevent spoofing attacks that can redirect traffic or compromise network integrity. Techniques such as DHCP snooping, dynamic ARP inspection (DAI), and IP-MAC binding help protect against ARP-related attacks. Understanding ARP operation, caching, security considerations, and its integration with Layer 2 and Layer 3 is essential for Cisco 350-401 ENCOR exam candidates. Proper ARP implementation ensures efficient local communication, reliable network performance, and secure operations within VLANs and enterprise subnets.
Question 19:
Which protocol is used to exchange routing information between routers within the same autonomous system?
A) OSPF
B) BGP
C) HSRP
D) NAT
Answer:
A) OSPF
Explanation:
Open Shortest Path First (OSPF) is a link-state routing protocol used to exchange routing information between routers within the same autonomous system (AS). OSPF is widely deployed in enterprise networks due to its scalability, efficiency, and fast convergence. Unlike distance-vector protocols, which rely on periodic updates, OSPF routers maintain a complete map of the network topology through the link-state database. This allows each router to independently calculate the shortest path to each network destination using the Dijkstra algorithm.
OSPF uses areas to improve scalability and limit the size of routing tables. Area 0, known as the backbone, interconnects other areas and provides a hierarchical design that reduces routing overhead. Routers within the same area exchange detailed link-state advertisements (LSAs), while routers between areas exchange summarized routes. This design reduces unnecessary flooding of routing information and allows OSPF to scale efficiently across large enterprise networks.
Fast convergence is another key characteristic of OSPF. When a link or router fails, OSPF quickly recalculates the shortest path using updated LSAs. This minimizes network downtime and ensures that critical enterprise applications, such as VoIP, ERP systems, and cloud services, continue to operate without interruption. OSPF also supports authentication, which secures routing updates from unauthorized devices, and VLSM, which optimizes IP address allocation.
Other protocols listed in the options serve different purposes. BGP is a path-vector protocol used for routing between autonomous systems, typically in ISP or multi-AS environments, and is not primarily used for intra-AS routing. HSRP provides default gateway redundancy but does not exchange routing information. NAT translates private IP addresses for connectivity to public networks but does not handle routing updates.
Understanding OSPF is essential for Cisco 350-401 ENCOR exam candidates. Candidates should know how OSPF establishes neighbor relationships, forms adjacency, exchanges LSAs, and calculates the shortest path tree. Knowledge of areas, backbone design, route summarization, and fast convergence is critical for designing resilient and scalable enterprise networks. Proper OSPF deployment ensures efficient routing, rapid fault recovery, and optimized network performance. In large-scale networks, OSPF reduces administrative complexity and supports dynamic changes in topology without impacting business operations.
Question 20:
Which feature of Cisco DNA Center allows centralized monitoring and troubleshooting of network devices?
A) Assurance
B) Policy-based automation
C) CLI configuration
D) VLAN assignment
Answer:
A) Assurance
Explanation:
Cisco DNA Center Assurance is a feature that provides centralized monitoring, analysis, and troubleshooting of network devices across enterprise networks. It is a core component of Cisco’s intent-based networking framework, allowing network engineers to proactively manage network health, performance, and security. Assurance leverages telemetry data, device health scores, application performance metrics, and client connectivity statistics to provide actionable insights. This centralized visibility helps identify performance issues, configuration errors, or security threats before they impact end users or critical applications.
Assurance collects data from multiple sources, including switches, routers, wireless controllers, access points, and endpoints. This data is analyzed in real-time to generate network health scores, identify anomalies, and provide root cause analysis. For example, if a branch site experiences slow application performance, Assurance can help determine whether the issue is due to bandwidth constraints, misconfigured QoS policies, or faulty network devices. By providing a unified dashboard, Assurance simplifies troubleshooting and reduces mean time to repair (MTTR).
Assurance also integrates with policy-based automation, allowing automated corrective actions in response to detected issues. It supports predictive analysis, enabling network administrators to anticipate failures and optimize network performance. Historical data analysis allows trend monitoring and capacity planning, which is critical for large enterprise networks that are constantly evolving with new devices, applications, and users.
Other options serve different purposes. Policy-based automation enables configuration deployment and policy enforcement but does not provide monitoring or troubleshooting insights. CLI configuration is manual device management and lacks centralized visibility. VLAN assignment segments the network but does not provide analytics or health monitoring.
Understanding Cisco DNA Center Assurance is vital for Cisco 350-401 ENCOR exam candidates. Knowledge of its capabilities, telemetry sources, network health scoring, analytics, and troubleshooting workflows equips network engineers to proactively manage enterprise networks, ensure application performance, and maintain high availability. Assurance enhances operational efficiency, supports proactive problem resolution, and reduces downtime, which are key objectives in enterprise network design and management.
Question 21:
Which technology allows multiple sites to securely communicate over a public network without requiring permanent point-to-point connections?
A) DMVPN
B) VLAN
C) HSRP
D) STP
Answer:
A) DMVPN
Explanation:
Dynamic Multipoint Virtual Private Network (DMVPN) is a Cisco solution that allows multiple enterprise sites to securely communicate over a public network, such as the internet, without requiring permanent point-to-point VPN connections. DMVPN enables a scalable, flexible, and cost-effective WAN architecture by dynamically establishing direct tunnels between sites as needed. It is especially useful for enterprises with many branch offices, reducing the administrative overhead and bandwidth consumption associated with traditional full-mesh VPN deployments.
DMVPN uses a combination of technologies, including multipoint GRE tunnels, Next Hop Resolution Protocol (NHRP), and IPsec encryption. The central hub maintains mappings of branch IP addresses and initiates on-demand tunnels to other branches, allowing spokes to communicate directly without routing traffic through the hub for every communication. This reduces latency, improves efficiency, and optimizes WAN bandwidth utilization. IPsec provides security, ensuring confidentiality, integrity, and authentication of data across public networks.
The primary advantage of DMVPN is its scalability. Traditional point-to-point VPNs require a separate tunnel for each site pair, which becomes complex and difficult to manage as the number of sites increases. DMVPN eliminates this limitation by creating on-demand tunnels dynamically and automatically. Routing protocols like EIGRP, OSPF, or BGP can operate over DMVPN, enabling dynamic route updates and fast convergence in case of link or hub failure.
Other options listed in the question perform different functions. VLAN segments traffic at Layer 2 but does not provide secure site-to-site communication. HSRP provides default gateway redundancy within a subnet but does not enable inter-site communication. STP prevents Layer 2 loops but is unrelated to WAN connectivity or VPN deployment.
Understanding DMVPN is essential for Cisco 350-401 ENCOR exam candidates. Candidates should know how DMVPN uses multipoint GRE, NHRP, and IPsec to provide scalable, secure, and dynamic connectivity between sites. Knowledge of hub-and-spoke versus full-mesh deployments, routing protocol integration, failover mechanisms, and configuration best practices is critical for designing resilient and efficient enterprise WAN architectures. DMVPN reduces complexity, improves network performance, and provides secure communication between multiple sites without requiring permanent point-to-point connections.
Question 22:
Which mechanism is used in an enterprise network to enforce Quality of Service policies based on traffic type?
A) Classification and marking
B) NAT
C) VLAN
D) HSRP
Answer:
A) Classification and marking
Explanation:
Classification and marking are foundational mechanisms in enterprise networks for enforcing Quality of Service (QoS) policies. QoS is essential to prioritize certain types of traffic, such as voice, video, or mission-critical applications, over best-effort traffic, ensuring predictable network performance and user experience. In enterprise networks, congestion can occur at various points, such as WAN links, core switches, or routers. Without QoS, important traffic may suffer delays or packet loss, which can significantly impact sensitive applications like VoIP or video conferencing.
Classification involves examining incoming packets and determining their traffic type based on Layer 2, Layer 3, or Layer 4 information. For example, a network device can inspect IP addresses, TCP/UDP ports, protocol types, or DSCP values to classify traffic into categories such as voice, video, or data. Marking is the process of labeling the packets with specific QoS identifiers, such as DSCP (Differentiated Services Code Point) or CoS (Class of Service), which guide routers and switches in handling packets appropriately throughout the network.
Once classified and marked, packets are subjected to policy enforcement using queuing mechanisms, shaping, or policing. Queuing strategies, such as Low Latency Queuing (LLQ) for voice traffic, prioritize critical traffic to reduce jitter and delay. Traffic shaping regulates the flow of packets to avoid congestion, while policing enforces bandwidth limits for certain traffic types to prevent overuse of resources. These mechanisms collectively ensure that high-priority traffic receives the necessary bandwidth and low-latency treatment while less critical traffic is handled on a best-effort basis.
Other options listed in the question serve different functions. NAT translates private IP addresses to public IP addresses for connectivity across networks but does not enforce QoS. VLAN provides segmentation and isolation but does not prioritize traffic. HSRP provides default gateway redundancy but has no role in traffic classification or policy enforcement.
Understanding classification and marking is critical for Cisco 350-401 ENCOR exam candidates. Candidates should be able to identify how traffic is classified, how marking informs subsequent network devices, and how QoS policies are applied to ensure predictable application performance. Knowledge of DSCP values, CoS, queuing mechanisms, shaping, and policing allows network engineers to design and implement enterprise networks that can handle mixed workloads efficiently. Proper QoS implementation ensures that critical business applications maintain performance under congestion, enhances user experience, and supports enterprise network reliability.
Question 23:
Which enterprise network service allows for automated deployment of device configurations and policy enforcement across multiple switches?
A) Cisco DNA Center automation
B) VLAN segmentation
C) STP
D) HSRP
Answer:
A) Cisco DNA Center automation
Explanation:
Cisco DNA Center automation is a critical feature for enterprise networks that enables centralized deployment, configuration, and policy enforcement across multiple network devices. In large-scale enterprise environments, manually configuring switches, routers, and access points is time-consuming, error-prone, and inefficient. DNA Center automation simplifies network management by allowing administrators to define network policies, configuration templates, and workflows centrally, which are then applied automatically to all managed devices.
DNA Center uses intent-based networking principles to translate business requirements into network configurations. For example, an administrator can define policies for user groups, device types, or application traffic, and DNA Center will automatically provision the necessary VLANs, access control, QoS policies, and security settings across the network. This ensures consistency, reduces configuration errors, and accelerates network deployment, particularly when adding new sites or devices.
The automation framework also supports real-time monitoring and verification, enabling administrators to confirm that the desired state matches the operational state. This continuous validation ensures compliance with security policies, proper segmentation, and adherence to service-level agreements. Automation workflows can include zero-touch provisioning for new devices, policy-based device onboarding, and scheduled configuration updates, reducing operational overhead and human intervention.
Other options listed in the question perform different functions. VLAN segmentation isolates traffic but does not automate deployment. STP prevents Layer 2 loops but does not manage device configurations. HSRP provides gateway redundancy but has no role in centralized policy or configuration automation.
Cisco DNA Center automation is essential for Cisco 350-401 ENCOR exam candidates. Candidates should understand the concepts of intent-based networking, policy creation, template deployment, and the role of automation in scaling enterprise networks. By using DNA Center automation, network engineers can ensure rapid provisioning, consistent security enforcement, and efficient operation of large enterprise networks. Automation reduces operational complexity, improves compliance, and enhances overall network performance, making it a critical skill for enterprise network professionals.
Question 24:
Which enterprise network design approach uses a two-tier architecture to provide high availability and scalability?
A) Collapsed core
B) Hub-and-spoke
C) Full-mesh
D) Point-to-point
Answer:
A) Collapsed core
Explanation:
A collapsed core design is a two-tier network architecture commonly used in enterprise environments to provide high availability, scalability, and simplified management. Unlike traditional three-tier designs, which include access, distribution, and core layers, the collapsed core merges the distribution and core layers into a single layer. This approach reduces the number of devices, simplifies the network topology, and lowers operational and capital expenditures while still maintaining redundancy and high availability.
In a collapsed core design, the access layer connects end devices, such as desktops, IP phones, or wireless access points, while the collapsed core layer handles routing between VLANs, Layer 3 forwarding, and connectivity to WAN or data center resources. Redundancy is achieved by deploying multiple core switches, with each access switch connected to two core switches for failover. This ensures uninterrupted connectivity in the event of a core switch failure and supports high availability for mission-critical applications.
The collapsed core architecture is suitable for medium to large enterprises where reducing the number of network devices is desired without sacrificing performance or resiliency. It supports high-speed uplinks, policy enforcement, and Layer 3 routing capabilities, allowing enterprises to scale the network as user and application demands grow. Design considerations include link aggregation, redundancy protocols like HSRP for gateway failover, and integration with QoS policies and security controls.
Other options listed in the question serve different purposes. Hub-and-spoke is a WAN topology for connecting multiple sites but does not define a campus network design. Full-mesh provides redundancy but is generally applied in WAN topologies and is not a scalable two-tier design for enterprise campuses. Point-to-point links connect only two devices and do not provide scalable, redundant enterprise network architecture.
Understanding collapsed core design is critical for Cisco 350-401 ENCOR exam candidates. Candidates should know its advantages, including simplified management, reduced device count, high availability, and integration with enterprise features such as routing, redundancy, QoS, and security. Proper implementation of a collapsed core ensures a resilient, scalable network capable of supporting enterprise growth, centralized management, and consistent performance across critical applications. Knowledge of link redundancy, Layer 3 routing, and integration with WAN connections is essential for designing robust enterprise networks using the collapsed core model.
Question 25:
Which feature allows Cisco switches to provide voice traffic prioritization over data traffic in an enterprise network?
A) Quality of Service
B) VLAN
C) STP
D) HSRP
Answer:
A) Quality of Service
Explanation:
Quality of Service (QoS) is a set of technologies and mechanisms used in enterprise networks to prioritize critical traffic over less time-sensitive traffic. In an environment where voice, video, and data traffic share the same network infrastructure, QoS ensures that latency-sensitive applications, such as VoIP and video conferencing, receive higher priority over standard data traffic. Without QoS, voice traffic can experience delays, jitter, and packet loss during congestion, resulting in poor call quality and a negative user experience.
QoS operates by classifying, marking, queuing, and scheduling network traffic. Classification involves examining the packet headers to determine the type of traffic based on parameters such as IP addresses, TCP/UDP ports, protocol types, or DSCP values. Once classified, packets are marked with identifiers that convey their priority level to downstream devices. This marking allows switches and routers throughout the network to apply appropriate handling mechanisms.
Queuing strategies are then used to manage the flow of traffic. For example, Low Latency Queuing (LLQ) is commonly employed for voice traffic to ensure minimal delay. Traffic shaping is used to control the flow of packets and smooth out bursts, while policing enforces bandwidth limits on lower-priority traffic. By combining classification, marking, and queuing, QoS ensures that critical applications receive predictable performance even in periods of network congestion.
QoS is not limited to Layer 3; it also operates at Layer 2 using Class of Service (CoS) values. Enterprise switches can map CoS values to DSCP markings, ensuring that both wired and wireless networks enforce consistent traffic prioritization. Additionally, QoS policies can be dynamically applied based on user roles, application types, or endpoint device characteristics, providing fine-grained control over traffic management.
Other options serve different functions. VLAN provides segmentation and isolation but does not prioritize traffic. STP prevents Layer 2 loops but does not handle traffic prioritization. HSRP provides gateway redundancy but does not influence traffic handling.
Understanding QoS is essential for Cisco 350-401 ENCOR exam candidates. Candidates must grasp the concepts of traffic classification, marking, queuing, shaping, and policing. They should also understand how to configure QoS policies for voice and video traffic, map CoS to DSCP, and troubleshoot QoS issues. Proper implementation of QoS ensures that enterprise networks can meet the performance requirements of latency-sensitive applications, improve user experience, and maintain network reliability. Knowledge of QoS contributes to the design of resilient, high-performance networks capable of supporting modern enterprise workloads.
Question 26:
Which technology enables secure wireless client authentication using centralized user credentials in an enterprise network?
A) 802.1X
B) VLAN
C) NAT
D) STP
Answer:
A) 802.1X
Explanation:
802.1X is a network access control protocol widely used in enterprise networks to secure wired and wireless client connections. It provides centralized authentication by requiring clients to validate their credentials with a remote authentication server before gaining access to the network. Typically, this involves communication with a RADIUS server that verifies usernames and passwords, digital certificates, or other credentials. 802.1X ensures that only authorized users and devices can access the network, enhancing security and protecting sensitive resources.
The 802.1X framework includes three components: the supplicant, the authenticator, and the authentication server. The supplicant is the client device requesting network access. The authenticator is typically a switch or wireless access point that enforces authentication, allowing or denying access based on the result from the authentication server. The authentication server, often a RADIUS server, verifies the credentials and informs the authenticator of the client’s authorization status.
In wireless networks, 802.1X is commonly used with WPA2-Enterprise or WPA3-Enterprise security protocols. These protocols rely on 802.1X authentication to provide per-user encryption keys and prevent unauthorized access. 802.1X also supports dynamic VLAN assignment, where authenticated users are placed in specific VLANs based on their roles, further enhancing network security and segmentation.
Other options in the question serve different purposes. VLAN isolates traffic but does not authenticate users. NAT provides IP address translation for connectivity across networks but does not handle authentication. STP prevents Layer 2 loops but does not provide security or client authentication.
Understanding 802.1X is crucial for Cisco 350-401 ENCOR exam candidates. Candidates should know how 802.1X works in both wired and wireless networks, the roles of supplicant, authenticator, and authentication server, and how it integrates with RADIUS for centralized authentication. They should also understand dynamic VLAN assignment, certificate-based authentication, and troubleshooting common 802.1X issues. Proper implementation of 802.1X enhances enterprise network security, ensures compliance with access control policies, and protects critical resources from unauthorized access, making it a fundamental technology in modern secure networks.
Question 27:
Which enterprise network design principle allows multiple devices to share redundant links without causing broadcast storms?
A) Spanning Tree Protocol
B) HSRP
C) NAT
D) VLAN
Answer:
A) Spanning Tree Protocol
Explanation:
Spanning Tree Protocol (STP) is a key enterprise network design principle used to prevent loops in Layer 2 networks while allowing redundant links for high availability. In enterprise networks, redundancy is critical to ensure uninterrupted connectivity and fault tolerance. Multiple physical paths between switches provide redundancy but can create switching loops, where frames circulate indefinitely, consuming bandwidth and causing broadcast storms. STP addresses this issue by creating a loop-free logical topology, selectively blocking certain redundant paths while keeping active paths operational.
STP operates by electing a root bridge, which serves as a central reference point. Each switch calculates the shortest path to the root bridge using path costs assigned to interfaces. Ports that are not part of the shortest path are placed in a blocking state, preventing loops. If a link fails, STP recalculates the topology and unblocks an alternate path, maintaining connectivity without human intervention.
Rapid Spanning Tree Protocol (RSTP) enhances STP by providing faster convergence times. While traditional STP can take tens of seconds to respond to a topology change, RSTP reduces downtime to a few seconds. This faster response is critical in enterprise networks supporting latency-sensitive applications such as VoIP or video streaming. Multiple Spanning Tree Protocol (MSTP) allows grouping VLANs into separate spanning tree instances, optimizing bandwidth utilization while maintaining loop prevention.
Other options in the question serve different functions. HSRP provides gateway redundancy but does not prevent Layer 2 loops. NAT translates IP addresses for connectivity but does not manage redundancy or broadcast storms. VLAN segments traffic but does not inherently prevent loops.
Understanding STP is essential for Cisco 350-401 ENCOR exam candidates. Candidates must understand root bridge election, port roles (root, designated, blocked), port states, and convergence behavior. Proper STP deployment ensures stable, loop-free Layer 2 topologies, supports network redundancy, and prevents broadcast storms. Knowledge of STP variants such as RSTP and MSTP allows engineers to design scalable and resilient enterprise networks capable of supporting high availability and performance. Correct implementation of STP reduces downtime, ensures efficient use of redundant links, and maintains network reliability, making it a critical principle in enterprise network design.
Question 28:
Which technology allows a Cisco router to maintain multiple simultaneous virtual connections with remote sites over a single physical interface?
A) DMVPN
B) VLAN
C) HSRP
D) STP
Answer:
A) DMVPN
Explanation:
Dynamic Multipoint Virtual Private Network (DMVPN) is a scalable Cisco solution designed for enterprise networks that require secure, flexible, and efficient connectivity between multiple remote sites without the need for permanent point-to-point tunnels. Traditional VPN solutions often require manually configured point-to-point connections between sites, which can become complex, difficult to manage, and costly as the number of sites increases. DMVPN addresses these limitations by enabling a single physical interface on a router to support multiple dynamic virtual tunnels to remote sites, reducing administrative overhead while maintaining security and connectivity.
DMVPN uses a combination of technologies, including multipoint GRE (mGRE) tunnels, Next Hop Resolution Protocol (NHRP), and IPsec encryption. The multipoint GRE tunnel allows a single interface to support multiple logical connections to different remote sites. NHRP provides a mechanism for mapping IP addresses to tunnel endpoints, allowing remote sites to dynamically discover each other and establish direct tunnels as needed. IPsec ensures that all communications are encrypted, providing confidentiality, integrity, and authentication across public networks such as the internet.
In a typical hub-and-spoke DMVPN deployment, a central hub router acts as the initial point of contact for all spokes. When a spoke wants to communicate with another spoke, it first contacts the hub to obtain the mapping information of the destination spoke. Once this information is obtained, a direct tunnel is established between the two spokes, bypassing the hub for the majority of the traffic. This on-demand approach reduces latency, optimizes bandwidth usage, and improves overall network performance compared to traditional hub-and-spoke VPN architectures.
DMVPN supports dynamic routing protocols such as EIGRP, OSPF, and BGP over the tunnels, allowing remote sites to exchange routing information efficiently and adapt to changes in network topology. The ability to dynamically establish tunnels also provides high availability, as failed links can be quickly bypassed, and alternate paths can be used to maintain connectivity. Administrators can also configure DMVPN with multiple hubs for redundancy, ensuring continuous network operation even if one hub fails.
Other options listed in the question serve different purposes. VLAN provides network segmentation but does not establish secure site-to-site connections. HSRP ensures gateway redundancy for hosts within a subnet but does not facilitate WAN connectivity. STP prevents Layer 2 loops but does not provide secure communication between remote sites.
Understanding DMVPN is critical for Cisco 350-401 ENCOR exam candidates. Candidates should know how DMVPN leverages mGRE, NHRP, and IPsec to provide scalable, secure connectivity between sites, how hub-and-spoke and full-mesh configurations differ, and how dynamic routing integrates with DMVPN tunnels. Knowledge of configuration, troubleshooting, and best practices ensures efficient and resilient WAN deployments, reduces operational complexity, and provides secure communication for geographically dispersed enterprise networks. Proper DMVPN implementation improves latency, optimizes bandwidth, and enhances the overall user experience by dynamically connecting remote sites without requiring permanent tunnels or extensive manual configuration.
Question 29:
Which protocol allows for the segmentation and isolation of network traffic to improve security and performance within an enterprise network?
A) VLAN
B) HSRP
C) OSPF
D) NAT
Answer:
A) VLAN
Explanation:
Virtual Local Area Network (VLAN) is a Layer 2 network segmentation technology used in enterprise networks to isolate broadcast domains, improve security, and enhance overall network performance. In a traditional flat network, all devices share a single broadcast domain, which can lead to excessive broadcast traffic, increased collisions, and potential security risks. VLANs address these issues by logically dividing a physical network into multiple, independent broadcast domains, allowing network administrators to group devices based on function, department, or security requirements regardless of their physical location.
Each VLAN functions as an independent Layer 2 network with its own broadcast domain. Devices within the same VLAN can communicate directly, while communication between VLANs requires a Layer 3 device, typically a router or a Layer 3 switch, to perform inter-VLAN routing. This logical separation ensures that traffic from one VLAN does not interfere with traffic from another, reducing congestion and improving network performance. VLANs are commonly used to separate voice traffic from data traffic, create isolated environments for sensitive applications, or provide segmentation for different organizational units.
VLANs also enhance network security by controlling which devices can communicate with each other. By isolating traffic, administrators can enforce access control policies, limit the impact of broadcast storms, and reduce the risk of unauthorized access to sensitive systems. VLAN tagging, based on IEEE 802.1Q, allows VLAN information to be carried across trunk links between switches, ensuring consistent segmentation throughout the network. VLAN membership can be configured statically or dynamically using protocols such as VLAN Membership Policy Server (VMPS).
Other options listed in the question serve different purposes. HSRP provides default gateway redundancy but does not segment or isolate traffic. OSPF is a Layer 3 routing protocol used to exchange routing information but does not manage broadcast domains or isolate Layer 2 traffic. NAT translates private IP addresses to public addresses for connectivity but does not provide traffic segmentation or isolation.
Understanding VLANs is essential for Cisco 350-401 ENCOR exam candidates. Candidates should know how VLANs function at Layer 2, how VLAN tagging works, how inter-VLAN routing is implemented, and how VLANs improve security and performance. Proper VLAN design and implementation ensure that enterprise networks are scalable, efficient, and secure, supporting organizational policies, reducing broadcast traffic, and providing predictable application performance. VLANs also simplify network management by logically grouping devices and allowing administrators to enforce consistent policies across the enterprise.
Question 30:
Which routing protocol supports fast convergence, hierarchical design, and authentication in enterprise networks?
A) OSPF
B) RIP
C) NAT
D) HSRP
Answer:
A) OSPF
Explanation:
Open Shortest Path First (OSPF) is a widely used link-state routing protocol designed for enterprise networks, offering fast convergence, hierarchical network design, and support for authentication to ensure secure routing updates. OSPF is a dynamic routing protocol that enables routers to share information about network topology and calculate the most efficient paths to each network destination using the Dijkstra shortest path first (SPF) algorithm. Unlike distance-vector protocols such as RIP, OSPF maintains a complete map of the network in its link-state database, allowing each router to independently compute the best routes based on the current topology.
OSPF supports hierarchical design through the use of areas, which reduce routing overhead and enhance scalability. The backbone area (Area 0) interconnects all other areas and serves as a central point for routing traffic. By grouping routers into areas, OSPF limits the propagation of detailed link-state information to within an area, while summarized routes are shared between areas. This hierarchical structure improves efficiency, reduces memory and CPU usage on routers, and allows large enterprise networks to scale effectively without performance degradation.
OSPF also supports fast convergence. When a network link or router fails, OSPF quickly recalculates the SPF tree and updates routing tables, typically within seconds. This rapid convergence minimizes downtime and ensures continuous connectivity for critical applications such as voice, video, and business-critical data. OSPF’s ability to detect topology changes and adapt quickly makes it suitable for environments where reliability and performance are essential.
Authentication is another key feature of OSPF. OSPF supports both plain-text and MD5 authentication, allowing routers to verify the authenticity of received routing updates. This protects against unauthorized or malicious routing information, ensuring that only trusted devices influence network routing decisions. Security is particularly important in enterprise networks where OSPF operates across multiple locations and integrates with other routing domains.
Other options in the question perform different functions. RIP is a distance-vector protocol with slower convergence and limited scalability. NAT provides IP address translation for connectivity but does not perform routing. HSRP ensures default gateway redundancy but does not exchange routing information or converge dynamically.
Understanding OSPF is essential for Cisco 350-401 ENCOR exam candidates. Candidates should be proficient in OSPF operation, including neighbor relationships, link-state advertisement types, SPF calculation, area design, route summarization, and authentication. Proper OSPF implementation ensures that enterprise networks are resilient, scalable, and secure. Knowledge of OSPF features allows network engineers to design robust network architectures capable of supporting high-performance applications, rapid recovery from failures, and secure, efficient routing across complex enterprise environments. OSPF’s hierarchical design, fast convergence, and security features make it a cornerstone protocol for enterprise network operations, ensuring reliability and operational excellence.