CCT Routing & Switching Free Practice Test — 30 Questions

Question 1

Consider a scenario where Router R1 is configured with both OSPF and EIGRP. R1 learns about the destination network 192.168.10.0/24 via two different paths. The OSPF process on R1 has an incoming route with an OSPF cost of 30. Simultaneously, the EIGRP process on R1 has learned the same destination network with an EIGRP composite metric of 2800. Assuming default administrative distances and no route redistribution or summarization that would alter these values, what path will Router R1 install in its routing table for the network 192.168.10.0/24, and why?

Accepted Answer

The EIGRP route will be installed because EIGRP has a lower administrative distance (90) compared to OSPF (110), making it the preferred protocol.

Question 2

A network engineer is implementing Quality of Service (QoS) on a core router interface to manage traffic flow. They configure Weighted Fair Queuing (WFQ) to prioritize real-time video conferencing traffic, assigning it a higher priority weight than standard web browsing traffic. Concurrently, they apply traffic shaping to the same interface, limiting the committed information rate (CIR) to 50 Mbps with a maximum burst size (Bc) of 10 Mbps. If the video conferencing traffic, due to its inherent bursty nature and high priority, consistently attempts to transmit at an instantaneous rate of 60 Mbps, what is the most likely consequence for the latency experienced by these video conferencing packets?

Accepted Answer

Increased latency due to buffering by the traffic shaping mechanism to conform to the CIR.

Question 3

Anya, a network architect, is tasked with diagnosing persistent, low-level packet loss on a newly integrated, heterogeneous WAN fabric connecting several critical data centers. The loss manifests sporadically, impacting real-time voice and video services but not consistently triggering alarms. Anya must isolate the root cause without causing service degradation or requiring a network-wide outage, as business operations are highly sensitive to downtime. She needs to leverage her understanding of various routing protocols, vendor-specific behaviors, and the ability to adapt her troubleshooting methodology based on real-time observations and limited available data.

Which of the following diagnostic strategies best aligns with Anya\'s constraints and the nature of the problem, demonstrating a blend of technical acumen and behavioral competencies for effective resolution?

Accepted Answer

Implement a phased approach: begin by analyzing end-to-end path telemetry and device logs for anomalies, correlate interface statistics for micro-bursts or errors, and then incrementally employ targeted, low-impact diagnostics on suspected segments, prioritizing non-disruptive methods like traceroute with small packet sizes and ICMP echo requests, while maintaining clear communication with stakeholders about the diagnostic progress and potential findings.

Question 4

Anya, a senior network engineer for a multinational corporation, is tasked with resolving persistent, intermittent connectivity disruptions affecting critical business applications across several continents. Users report slow response times and occasional session drops for services like CRM and ERP, particularly during peak hours. Standard diagnostic tools like ping and traceroute show inconsistent results, with some paths appearing normal while others exhibit high latency or packet loss, often changing without apparent configuration modifications. The network infrastructure comprises diverse routing protocols, multiple security zones enforced by stateful firewalls, and various Quality of Service (QoS) policies designed to prioritize critical traffic. Anya suspects the issue might stem from the complex interaction between routing protocol convergence, dynamic path selection influenced by traffic load, and the stateful inspection mechanisms of the firewalls. Which core competency is paramount for Anya to effectively diagnose and resolve this multifaceted network challenge?

Accepted Answer

Systematic issue analysis and root cause identification

Question 5

Anya, a senior network architect, is spearheading a critical, multi-phase migration from a proprietary routing protocol to an industry-standard, open-source solution across a global enterprise. The existing protocol is known for its stability but suffers from vendor lock-in and slow convergence times, impacting real-time application performance. The new protocol promises enhanced flexibility and interoperability but introduces complexities in its configuration and management, especially in heterogeneous network environments. During the initial pilot deployment at a secondary data center, unexpected interoperability issues arose with a specific vendor\'s legacy firewall, requiring a significant deviation from the planned configuration and a temporary rollback of certain features. This incident has created uncertainty regarding the timeline for subsequent site rollouts and the precise technical adjustments needed for other sites with similar, though not identical, firewall vendors.

Which behavioral competency is most crucial for Anya to effectively navigate this evolving situation and ensure the successful completion of the migration project?

Accepted Answer

Adaptability and Flexibility

Question 6

Consider a scenario within a large enterprise network where a core router, designated as R1, experiences a sudden failure of its primary link to a critical data center. This link is advertised via OSPF. Following the detection of this link failure and the subsequent notification to its neighbors, what is the immediate and primary action R1 must undertake to ensure its routing table accurately reflects the new network state?

Accepted Answer

Initiate a full SPF recalculation based on the updated link-state database.

Question 7

Anya, a senior network engineer for a multinational corporation, is alerted to a critical routing flap occurring on a core segment of the enterprise network. This instability is causing intermittent connectivity for a high-priority client, impacting a mission-critical financial application. The network utilizes a dynamic routing protocol, and the flapping is manifesting as frequent changes in route availability and next-hop advertisements. Anya needs to implement an immediate, effective, and scalable solution to mitigate the client\'s service disruption while preserving the overall network\'s dynamic routing capabilities. Which of the following technical interventions would best address the immediate issue of routing instability without compromising the network\'s long-term operational efficiency and resilience?

Accepted Answer

Implement route dampening parameters on the edge routers of the affected segment to suppress unstable routes.

Question 8

Anya, a network engineer responsible for a dual-site data center network, is troubleshooting intermittent packet loss and elevated latency on a critical WAN link. This link is managed by edge routers running BGP, with sophisticated path selection policies in place to ensure optimal connectivity. Standard diagnostics like checking physical layer integrity, interface error counters, and BGP adjacency status have yielded no clear anomalies. However, the performance degradation began shortly after the implementation of a new Quality of Service (QoS) policy designed to prioritize real-time traffic. The intermittent nature of the issue suggests a dynamic factor is at play, potentially related to how the QoS mechanisms interact with the underlying routing behavior.

Which of the following scenarios best explains the observed performance degradation, considering the interplay between BGP routing and QoS implementation?

Accepted Answer

The QoS policy's strict rate-limiting applied to certain traffic classes is causing excessive queue discards on the egress interface during peak traffic, leading to packet loss and increased latency, especially when BGP reconvergence briefly shifts traffic to a less optimal, congested path.

Question 9

Anya, a network architect, is troubleshooting performance degradation on a large enterprise network where real-time applications are experiencing increased jitter and packet loss. She has confirmed that the underlying dynamic routing protocol is operational but is selecting paths that, under certain load conditions, lead to suboptimal performance for voice and video traffic. Which of the following strategies would most effectively address this by influencing path selection based on application requirements without fundamentally altering the core routing protocol\'s convergence characteristics?

Accepted Answer

Implementing granular Quality of Service (QoS) policies with Policy-Based Routing (PBR) to steer traffic with specific DSCP markings to pre-defined or dynamically identified low-latency paths.

Question 10

Anya, a senior network architect, is leading a critical initiative to transition the enterprise\'s core routing infrastructure from an aging, proprietary protocol to a modern, open-standard protocol. This migration is essential for enhancing network agility, improving security posture, and reducing long-term operational costs. However, the project faces significant internal resistance due to the team\'s limited exposure to the new protocol, concerns about service continuity, and differing opinions on the optimal migration strategy among key stakeholders. Anya must orchestrate this complex change while ensuring minimal disruption and maximum team engagement. Which of the following approaches best encapsulates Anya\'s strategic deployment of behavioral competencies to navigate this challenging transition successfully?

Accepted Answer

Proactively establishing cross-functional working groups to collaboratively define migration phases, conduct rigorous parallel testing, and develop comprehensive rollback plans, while consistently communicating the strategic benefits and progress to all stakeholders and providing targeted training and mentorship to team members to build confidence and expertise in the new protocol.

Question 11

A network administrator is tasked with upgrading a critical segment of the enterprise backbone. This segment currently utilizes EIGRP and Cisco ISR routers. The plan is to migrate to OSPFv3 and Juniper MX series routers to improve scalability and support for IPv6. The primary constraint is zero tolerance for service interruption on this critical segment during the migration. Considering the need for stability and the potential for unforeseen issues with new hardware and protocols, what is the most appropriate methodology to ensure uninterrupted service delivery throughout this transition?

Accepted Answer

Configure the new Juniper routers with OSPFv3, establish adjacencies with the existing network, and then gradually shift traffic by manipulating routing metrics and advertisements to favor the new path, while maintaining the old routing protocol until full migration is verified.

Question 12

Consider a large enterprise network undergoing a significant routing protocol overhaul, migrating from an internal OSPF deployment to a multi-homed BGP architecture to support new cloud connectivity and increased ISP diversity. During the migration, unexpected BGP neighbor flapping occurs on several edge routers, impacting traffic flow and requiring immediate, on-the-fly adjustments to peering configurations and route advertisements. Which behavioral competency is most critical for the network engineering team to effectively navigate this complex and evolving transition?

Accepted Answer

Adaptability and Flexibility

Question 13

Consider a complex, multi-vendor routing infrastructure where a critical fiber optic link between two major distribution hubs experiences a sudden, intermittent failure. This instability triggers frequent route recalculations across multiple routing domains. Network administrators are observing significant degradation in application response times and an increase in transaction failures during these periods. To mitigate the impact of these rapid topological shifts and restore optimal network performance with minimal delay, which of the following proactive network design principles would most effectively expedite the network\'s return to a stable, fully converged state and reduce the duration of service disruption?

Accepted Answer

Implementing a comprehensive Fast Reroute (FRR) strategy, leveraging pre-calculated loop-free alternate paths at the edge and core of the network to bypass failed links and provide immediate traffic redirection.

Question 14

Considering a network segment where a router interface with a total capacity of 10 Mbps is configured to prioritize voice traffic. A QoS policy map assigns a traffic shaping rate of 2 Mbps to the voice traffic class and applies a Weighted Fair Queuing (WFQ) discipline with a weight of 64 for this class. If other traffic classes exist on the same interface with lower WFQ weights, what is the absolute maximum sustained bandwidth that the voice traffic can utilize, irrespective of the aggregate interface capacity or the behavior of other traffic classes?

Accepted Answer

2 Mbps

Question 15

Consider a large enterprise network utilizing OSPFv2 as its primary interior gateway protocol. The network experiences intermittent connectivity issues on several core links due to faulty hardware. This leads to frequent link state changes (up/down flapping) within a specific OSPF area. A network administrator observes that during these periods of instability, certain critical applications experience significant packet loss and intermittent reachability issues, even though the overall network topology should technically allow for alternative paths. What fundamental routing behavior is most likely being exacerbated by these rapid, recurring topology changes, leading to the observed application performance degradation?

Accepted Answer

Increased routing table instability and potential for temporary routing loops due to rapid LSA re-convergence.

Question 16

Anya, a senior network engineer responsible for a critical financial services client\'s infrastructure, is alerted to a complete network outage affecting all client services. Initial diagnostics reveal a catastrophic failure of the primary control plane on a vital edge router. The client\'s business operations are severely impacted, with real-time trading halted. Anya has mere minutes to restore connectivity. Considering the high-stakes environment and the immediate need for service restoration, what is Anya\'s most critical initial action to mitigate the client\'s business disruption?

Accepted Answer

Initiate failover to the secondary control plane to restore routing and forwarding functions.

Question 17

A network administrator is configuring BGP on Router A, which is peering with two external routers, Router B and Router C, both advertising the same destination network. Router A receives Route 1 from Router B with a locally configured Weight of 300 and a Local Preference of 150. Router A receives Route 2 from Router C with a locally configured Weight of 200 and a Local Preference of 100. Assuming all other BGP path attributes (AS_PATH, Origin, MED) are identical for both routes, which route will Router A select as the best path and why?

Accepted Answer

Router A will select Route 1 due to its higher Weight attribute, which is the first attribute evaluated in the Cisco BGP path selection process.

Question 18

During a critical international cybersecurity summit hosted at a large convention center, the primary fiber optic link to the internet fails unexpectedly, causing a complete outage for all attendees and presenters. The network operations team has a backup router with a different, less familiar operating system and a secondary, lower-bandwidth satellite uplink that was previously configured for contingency but never fully tested under load. The team has limited time before keynotes begin and needs to restore connectivity rapidly while managing the uncertainty and potential for misconfiguration. Which of the following strategies best balances immediate restoration, resource utilization, and effective team coordination in this high-pressure, ambiguous situation?

Accepted Answer

Immediately deploy the backup router using the satellite uplink, assigning specific engineers to configure the new OS and validate the secondary link, while designating a team lead to manage stakeholder communications and provide regular, simplified updates on progress and any limitations of the restored service.

Question 19

Anya, a network engineer managing a multi-area OSPF deployment, has configured route summarization at the ABR connecting Area 0 (backbone) and Area 1. She notices that a specific /24 network, which is part of the summarized block advertised into Area 0, has become unreachable from hosts in Area 0. However, other subnets within the same summarized block remain accessible. Analysis of the routing tables reveals that Area 0 still possesses a route for the summarized address range, but the specific /24 destination is now marked as inaccessible. Which of the following is the most likely underlying cause for this specific connectivity failure, considering the impact of route summarization on inter-area routing?

Accepted Answer

The specific /24 network within Area 1 has lost its direct connectivity to the ABR, but the ABR continues to advertise the summary route for the larger block into Area 0 because other subnets within that block are still reachable.

Question 20

Anya, a seasoned network engineer for a global logistics firm, is experiencing significant performance degradation for their Voice over IP (VoIP) communication system. Users are reporting garbled audio, dropped calls, and noticeable delays, directly impacting inter-departmental collaboration and client interactions. The network infrastructure comprises a mix of Cisco and Juniper routers and switches, with multiple WAN links and complex internal routing. Anya suspects that the Quality of Service (QoS) configurations, specifically for voice traffic, are not optimally implemented or are being overwhelmed. To effectively diagnose and resolve this critical issue, what approach should Anya prioritize to restore reliable voice communication?

Accepted Answer

Systematically identify the specific types of QoS degradation impacting voice traffic (packet loss, jitter, latency), verify the correct implementation of priority queuing mechanisms like Low Latency Queuing (LLQ) on relevant interfaces, and analyze link utilization patterns to pinpoint potential congestion points.

Question 21

Following a critical network outage impacting a major client\'s services, traced to a newly deployed edge router exhibiting instability during a topology change that triggered a high volume of dynamic routing updates, the immediate mitigation involved isolating the faulty device. The network engineering team subsequently reverted the affected segment to the previous router\'s configuration to restore service. Considering the need to redeploy the new router successfully and prevent recurrence, which diagnostic and corrective action sequence is most likely to achieve a stable and optimized integration, addressing the root cause of the routing protocol\'s failure to adapt to the network\'s dynamic state?

Accepted Answer

Conduct a thorough review of the new router's Border Gateway Protocol (BGP) session configurations, including neighbor states, timers, and the impact of applied route maps and Quality of Service (QoS) policies on routing update propagation and prioritization.

Question 22

In a network segment experiencing congestion, a router employs Weighted Fair Queuing (WFQ) to manage traffic. The WFQ configuration assigns weights of 10 to Voice traffic, 5 to Video traffic, and 2 to Data traffic. If the router\'s interface is saturated and all three traffic types are present, which of the following accurately describes the likely outcome of the WFQ scheduling mechanism in terms of packet transmission order and bandwidth allocation over a sustained period?

Accepted Answer

The router will predominantly transmit Voice packets, followed by Video, and then Data packets, with the service rate approximately reflecting the ratio of their assigned weights, ensuring higher-priority traffic receives a disproportionately larger share of the available bandwidth.

Question 23

Anya, a senior network architect for a global telecommunications provider, is alerted to a cascading routing failure impacting a significant enterprise client segment. The issue began subtly, manifesting as intermittent packet loss, but rapidly escalated into complete connectivity loss for several key services. Initial diagnostics suggest an anomaly in the BGP peering with a major transit provider, but the exact trigger remains elusive, and standard troubleshooting steps have yielded no definitive resolution. Anya\'s team is under immense pressure from the client and executive leadership to restore service immediately. She must coordinate efforts across multiple geographically dispersed teams, including routing engineers, security analysts, and client-facing support, all while the underlying cause is still being actively investigated and could involve unexpected protocol interactions or a novel vulnerability.

Which of Anya\'s core behavioral competencies is most critical for her to effectively navigate this complex and rapidly evolving network crisis and guide her teams toward a successful resolution?

Accepted Answer

Adaptability and Flexibility: Adjusting to changing priorities, handling ambiguity, maintaining effectiveness during transitions, and pivoting strategies when needed.

Question 24

Anya, a network engineer responsible for a large, multi-vendor enterprise network currently relying on RIPv2, is tasked with migrating to a more robust routing protocol like OSPF. The network supports critical business applications, and any prolonged downtime or routing instability is unacceptable. Anya must devise a strategy that ensures minimal disruption, allows for rollback if issues arise, and maintains optimal routing paths throughout the transition. What is the most prudent technical strategy Anya should employ to achieve this complex migration while demonstrating strong adaptability and problem-solving abilities in a high-pressure environment?

Accepted Answer

Implement a dual-protocol coexistence strategy, leveraging route maps and administrative distance manipulation to control redistribution between RIPv2 and OSPF, followed by a phased rollout and eventual decommissioning of RIPv2.

Question 25

Consider a network where Router A, operating within Autonomous System 65002, receives two distinct BGP paths to the network prefix 192.168.1.0/24 from different external peers. Path 1 originates from a neighbor within the same AS and possesses a Local Preference of 120 and an AS_PATH attribute of 65002. Path 2 originates from a neighbor in a different AS (AS 65001) and has a Local Preference of 100, with an AS_PATH attribute of 65001 65002. Assuming all other BGP attributes are either equal or not explicitly configured to influence the decision, which path will Router A select as the best path to reach 192.168.1.0/24 and why?

Accepted Answer

Path 1 will be selected because a higher Local Preference attribute is prioritized over a shorter AS_PATH attribute within the BGP best path selection algorithm.

Question 26

Following a recent firmware upgrade on a critical edge router responsible for inter-AS routing, Anya observes inconsistent traffic flow to a specific partner network, characterized by elevated latency and occasional packet drops. Standard `show ip route` and `ping` tests appear normal at a glance, suggesting the issue is not a simple route absence or complete connectivity failure. Anya needs to determine the most effective next step to diagnose the root cause, considering the upgrade may have altered underlying protocol behaviors or metric interpretations.

Accepted Answer

Scrutinize the routing protocol's convergence algorithm and metric calculation details for any subtle changes introduced by the firmware, examining logs for protocol re-initialization events or metric updates.

Question 27

During a critical system outage affecting a global financial exchange\'s trading platform, network engineer Anya identifies widespread routing table inconsistencies across core routers, leading to packet loss and service unavailability. The incident occurs during peak trading hours. Anya must quickly diagnose and mitigate the issue while keeping senior management informed. Which combination of competencies is most critical for Anya to effectively manage this crisis?

Accepted Answer

Rapid diagnostic analysis, clear and concise technical communication to stakeholders, and decisive action based on incomplete data.

Question 28

During the implementation of a core network routing upgrade utilizing BGP, a critical interoperability defect is discovered between the new vendor\'s equipment and the existing infrastructure, specifically concerning the propagation of BGP path attributes, leading to unstable routing. The project timeline is tight, and key stakeholders are increasingly anxious about potential service disruptions. Which of the following approaches best reflects effective behavioral competencies and technical judgment in this scenario?

Accepted Answer

Implement a temporary workaround on the existing infrastructure to stabilize routing while engaging the new vendor for a permanent solution, and communicate a revised, phased deployment plan to stakeholders.

Question 29

Anya, a seasoned network engineer, is tasked with upgrading the Quality of Service (QoS) implementation across a heterogeneous network environment comprising Cisco, Juniper, and Arista routing platforms. The objective is to prioritize real-time video conferencing traffic and sensitive financial data streams, which were not adequately accounted for in the previous, more generalized QoS policy. The transition must be seamless, minimizing disruption to existing, albeit lower-priority, services. Anya must select the most appropriate strategy to dynamically manage bandwidth allocation and queuing mechanisms across these diverse vendor implementations, considering potential compatibility issues and the need for granular control over traffic classes. Which of the following approaches best reflects the strategic thinking and adaptability required for this complex network upgrade, while adhering to best practices for inter-vendor QoS configuration?

Accepted Answer

Implement a unified, vendor-agnostic QoS policy framework leveraging DiffServ Code Points (DSCPs) for classification and then meticulously map these DSCPs to specific queuing and shaping policies on each vendor's platform, prioritizing LLQ for real-time traffic and CBWFQ for financial data, with careful configuration of WRED on egress interfaces to manage potential congestion proactively.

Question 30

Anya, a network engineer responsible for a company\'s inter-site connectivity, is investigating persistent, intermittent packet loss on a primary WAN link. Initial diagnostics confirm packet loss, particularly during periods of high network utilization, but do not point to a specific hardware failure or misconfiguration of basic routing protocols. The link\'s physical layer is verified, and standard link-level tests are nominal. Anya suspects that the issue is related to how traffic is managed during congestion. Which of the following investigative approaches would be most effective in pinpointing the root cause of this dynamic packet loss?

Accepted Answer

A detailed analysis of the Quality of Service (QoS) configuration, focusing on traffic shaping, policing, queuing mechanisms, and congestion avoidance policies applied to the affected WAN link.

CCT Routing & Switching Free Practice Test — 30 Questions

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