Free and Premium Cisco 400-007 Dumps Questions Answers

B (Minimize operational costs): A common business goal to reduce long-term operating expenses.

E (Reduce complexity): Simplifying designs reduces operational overhead, risk, and failure domains.

Why other options are incorrect:

A: Resiliency is a design goal, but not a business objective itself.

C: Endpoint posture is a technical security feature.

D: Faster obsolescence contradicts business optimization.

Dense Wavelength Division Multiplexing (DWDM) enables multiple optical signals to be transmitted simultaneously on different wavelengths over a single fiber, allowing:

B: Efficient bandwidth expansion without laying new fiber infrastructure.

C: Topology flexibility and service protection using built-in features like optical protection switching, automatic fault detection, and self-healing rings.

Why other options are incorrect:

A: Oversubscription of bandwidth applies more to packet-based networks, not DWDM optical layer.

D: Chromatic dispersion is managed but not an inherent “intelligent” feature in DWDM.

E: Service protection at the DWDM layer operates independently of upper layer protocols.

—

A (Financial and governance models): In the Define Strategy step, it's crucial to establish financial frameworks and governance structures that will guide the use of cloud services. This includes determining budgeting approaches (CapEx vs. OpEx), compliance, policy enforcement, risk management, and ownership of IT resources.

Governance models also define roles, responsibilities, and accountability for managing cloud services across the organization.

Other options explained:

B: Business alignment is important but comes after strategic governance and financial planning.

C: Due diligence is typically performed during vendor selection or migration readiness.

D: Contingency planning is part of exit or risk management phases, not the initial strategy step.

—

A (Fault management):Covers detection, isolation, notification, and resolution of network issues to ensure minimal downtime and service disruptions, directly aligning with the design goal of preventing and mitigating outages.

Other options explained:

B: Performance management monitors resource usage but doesn’t directly handle faults.

C: Security management handles authorization, authentication, and protection.

D: Accounting management deals with usage tracking for billing and auditing.

When a service provider does not support multicast over their Layer 3 VPN, the enterprise can useGRE tunnels between Customer Edge (CE) devicesto transport multicast traffic. This method allows the customer to encapsulate multicast packets in unicast GRE packets, which are routable through the provider’s non-multicast core.

In this scenario, the most scalable and immediate solution is to establish a GRE tunnel betweenC2 (in the head office CE router path)andC4 (at the branch office). This setup ensures that multicast traffic originating at the head office is tunneled directly to the multicast receivers, bypassing the service provider’s non-multicast-aware core.

This strategy is directly aligned with CCDE v3.1 principles, which emphasize:

Minimizing service provider dependency

Providing a scalable, customer-controlled overlay solution

Ensuring protocol compatibility across domains

Why other options are incorrect:

A: Tunnel between CE1 and CE2 is less optimal, as it may not originate or terminate at the exact multicast endpoints.

C: Tunnel between C1 and C4 is less aligned with CE-to-CE design expectations and may bypass required edge security/policy controls.

D: 2547oDMVPN is more complex and intended for full-scale VPN overlays, not quick multicast solutions.

E: Draft Rosen requires service provider support, which is currently unavailable, hence not a valid short-term option.

This solution ensures operational simplicity and future scalability with minimal provider dependency, which are core principles outlined in the CCDE v3.1 design methodology.

The IS-IS Overload Bit allows a router to signal to its peers that it should be temporarily excluded from SPF calculations for transit traffic:

A: The Overload Bit can be automatically set at startup (known as "startup overload") to allow the router sufficient time to converge IGP, BGP, and stabilize protocols before accepting transit traffic.

D: The bit can remain set until all dependent protocols have converged and the router is fully operational.

Why other options are incorrect:

B: The router’s directly connected prefixes remain reachable; only transit path calculations exclude the overloaded node.

C: MPLS-TE does not automatically reoptimize tunnels based on the Overload Bit.

E: There is no specific restriction preventing Overload Bit usage on Route Reflectors.

The two most common challenges for organizations adopting container technologies are:

B (Security): Containers introduce unique security challenges, such as shared kernels, namespace isolation, image vulnerabilities, and orchestration exposure.

E (Skilled staff): Containerization requires specialized skills in orchestration (e.g., Kubernetes), CI/CD, and microservices design, which may not be readily available in many IT teams.

Other options explained:

A: Performance is generally good for containers; overhead is minimal.

C: Cost savings are often a driver for containerization.

D: Deployment is streamlined via orchestration platforms.

F: Compliance is important but less frequently cited as the initial adoption barrier.

—

—

Let’s calculate total 1-year cost for each option using the provided table:

DWDM over dark fiber:

CAPEX = $250,000

OPEX (1 year) = $100,000

Installation fee = $30,000

Total = $250,000 + $100,000 + $30,000 = $380,000

CWDM over dark fiber:

CAPEX = $150,000

OPEX (1 year) = $100,000

Installation fee = $25,000

Total = $150,000 + $100,000 + $25,000 = $275,000

MPLS wires only:

CAPEX = $50,000

OPEX (1 year) = $80,000

Installation fee = $5,000

Total = $50,000 + $80,000 + $5,000 = $135,000

BUT: MPLS does not allow customer-controlled QoS policies as stated in the requirement (cannot run its own varying QoS profiles without SP interaction). Therefore disqualified.

Metro Ethernet:

CAPEX = $45,000

OPEX (1 year) = $100,000

Installation fee = $5,000

Total = $45,000 + $100,000 + $5,000 = $150,000

BUT: Metro Ethernet is also typically a service provider-managed solution where customer-controlled QoS is usually limited depending on SP capabilities. May not fully meet the requirement.

—

The key technical requirement:

“Be able to run its own varying QoS profiles without service provider interaction.”

This clearly favors dark fiber solutions (CWDM and DWDM), as these give full Layer 1 control to the customer, allowing complete freedom in managing QoS, traffic engineering, and prioritization internally.

Among the two dark fiber options, CWDM over dark fiber is the most cost-effective choice for one year at $275,000.

—

Therefore, final correct answer:

B (IP Source Guard):IP Source Guard prevents IP address spoofing at Layer 2 by binding IP-to-MAC addresses and filtering unauthorized source IPs. It operates independently of encryption, so it has no impact on encryption performance.

Other options explained:

A: MACsec adds encryption and has performance implications.

C: DHCP snooping with DAI focuses on ARP spoofing, not IP address antispoofing specifically.

D: IPsec handles encryption, which directly impacts performance.

In a standard 3-tier data center architecture (access, aggregation, core), the Layer 2-to-Layer 3 boundary typically resides at the aggregation layer. When extending VLANs between data centers using a Layer 2 interconnection, the most optimal and scalable termination point is at the aggregation layer because:

It naturally handles VLAN demarcation and Layer 3 boundary.

Spanning Tree Protocol (STP) domains remain contained within local aggregation blocks.

The core remains Layer 3-only, ensuring scalability, stability, and no STP involvement.

Simplifies traffic engineering, FHRP operations, and minimizes control-plane complexity across sites.

This design is consistent with CCDE v3.1 best practice where VLAN extension is isolated to aggregation to avoid STP scaling issues and maintain hierarchical design principles.

Why other options are incorrect:

A: STP isolation can still be achieved at aggregation while keeping the core Layer 3.

C: Access layer extensions would increase STP scope and complexity unnecessarily.

D: Core termination violates Layer 3 core design, bringing STP into the core, which is not scalable.

SD-WAN integrates multiple underlay transport options (Internet, MPLS, LTE) while delivering advanced features like DPI (Deep Packet Inspection), SLA monitoring, QoS, encryption, scalability, and centralized management.

It provides policy-based path selection, cost optimization, and rapid deployment.

SD-WAN is widely regarded as a modern WAN design solution fully aligned with CCDE v3.1 design principles for cost-effective and flexible WAN architectures.

Why other options are incorrect:

B: Internet alone cannot deliver consistent SLA or QoS guarantees.

C: Hybrid MPLS + Internet may work but is more complex and costly; SD-WAN natively supports such hybrid models.

D: MPLS offers SLAs but lacks flexibility, DPI, and cost-effectiveness compared to SD-WAN.

—

Cisco FabricPath is a Layer 2 multipath technology that blends traditional Layer 2 Ethernet with routing technologies to enable loop-free forwarding and scalability. Two critical mechanisms used to mitigate loops:

C. RPF (Reverse Path Forwarding) Check: FabricPath applies a reverse path forwarding check, similar to multicast, to verify the source of a frame and discard duplicates arriving on unexpected paths.

D. TTL Header: FabricPath adds a Time-To-Live (TTL) field to Layer 2 frames, which is not present in traditional Ethernet. This prevents indefinite circulation of frames by limiting their lifetime in the network—much like in IP.

These elements allow FabricPath to prevent broadcast storms and loops in multipath Layer 2 topologies, addressing legacy STP limitations with efficient loop-avoidance methods.

==========

B (IPFIX telemetry data):IPFIX provides detailed flow-level visibility, enabling identification of traffic patterns, data flows, and destinations. This data is critical for understanding current traffic behavior to identify governance gaps and improve policy compliance.

Other options explained:

A: Secure tunnels protect traffic but do not identify governance gaps.

C: Firewalls provide limited flow visibility compared to telemetry.

D: Workload policies enforce security but do not aid initial visibility analysis.

In Cisco Wireless Guest Anchor deployments, traffic between foreign and anchor controllers is typically tunneled using CAPWAP (Control and Provisioning of Wireless Access Points).

The CAPWAP tunnel operates over IP and can traverse MPLS VPN or VRF-Lite Layer 3 segmentation to maintain logical separation across different segments or geographic sites.

This allows end-to-end isolation of guest traffic from the enterprise network into the DMZ anchor location, as shown in the diagram.

Why other options are incorrect:

B: Unencapsulated traffic would expose guest traffic inside the enterprise network.

C: EoIP is not a standard Cisco wireless tunneling method.

D: IPinIP or IPsec tunnels are not typically used between WLCs for guest anchor tunneling.

B (Use only secure protocols): Management and administrative access to Internet edge routers must use secure protocols (SSH, SNMPv3, HTTPS) to prevent interception or unauthorized access.

E (Restrict administrative access): Limiting administrative access via interface ACLs and clear login banners ensures that only authorized personnel can access the system, satisfying compliance and security requirements.

Other options explained:

A: Filtering infrastructure IP space is good hygiene but not directly related to compliance.

C: Logging is valuable for operations and incident response but not a compliance control by itself.

D: EBGP advertisements relate to routing policy, not compliance regulation.

—

Cisco SD-WAN Cloud OnRamp SaaS optimizes cloud application performance by dynamically measuring SaaS application paths from multiple branch edges toward the Microsoft 365 cloud.

It automatically selects the best-performing path, continuously monitors SLA metrics (latency, loss, jitter), and dynamically reroutes based on real-time performance.

This directly addresses SaaS resiliency across multiple ISPs with minimal manual intervention and is aligned with CCDE v3.1 SD-WAN design methodologies for SaaS optimization.

Why other options are incorrect:

A: Cloud OnRamp gateway is for IaaS optimization (AWS, Azure), not SaaS.

B: Cloud OnRamp SWG (Secure Web Gateway) is for internet-bound security inspection, not SaaS path optimization.

C: "Cloud OnRamp" alone is too general; SaaS is the specific solution for this SaaS use case.

C (Transparent firewall): Operates at Layer 2, allowing filtering and inspection of traffic within the same subnet without requiring IP routing changes. It performs deep packet inspection while maintaining Layer 2 adjacency, making it ideal for intra-subnet traffic control in data centers.

This allows security segmentation inside broadcast domains, enforcing security policies even for east-west traffic.

Other options explained:

A: Routed firewalls require subnet boundaries and are not ideal for intra-subnet control.

B: VLAN ACLs provide basic filtering but lack deep packet inspection capabilities.

D: Zone-based firewalls are primarily designed for inter-subnet (Layer 3) traffic segmentation.

Private cloud architecture provides:

On-demand provisioning and decoupling from hardware

Security controls under enterprise ownership

Strong isolation — comparable to an air-gapped model if fully controlled on-premises or in a dedicated hosted environment

While public or hybrid clouds offer flexibility, they cannot guarantee security parity with air-gapped systems unless significant additional controls are implemented. Private cloud supports containerized architectures and modern DevOps pipelines, while keeping the data plane within enterprise boundaries.

This aligns with CCDE’s cloud design principles — balancing modernization goals with strict compliance and cybersecurity mandates.

==========

Public cloud offers scalability, flexibility, and consumption-based pricing, which directly reduces capital expenditures (CAPEX) and minimizes operational burden (less IT staff needed for infrastructure maintenance).

Public cloud eliminates upfront hardware investments and shifts cost to predictable operational expenses.

Public cloud providers handle hardware maintenance, upgrades, and scalability, making it highly cost-effective for government agencies with fluctuating workloads.

Why other options are incorrect:

A: On-premises increases CAPEX and requires significant IT staff.

B: Private cloud reduces some OpEx but still requires infrastructure management and higher CAPEX.

D: Hybrid cloud increases complexity and operational costs.

—

In a full-mesh iBGP design, every router must establish and maintain a BGP session with every other router. As the number of routers increases, the number of BGP sessions and the amount of BGP processing increases exponentially. This leads to high CPU utilization, especially in devices with limited processing capabilities, such as distribution routers.

Themost cost-effectiveandscalablesolution in this scenario is toimplement route reflectors (RRs)on the two core routers. Route reflectors significantly reduce the number of iBGP peerings required, eliminating the full mesh requirement by allowing the distribution routers (RR clients) to establish a single iBGP session with the route reflector. The route reflector handles route advertisement to other RR clients, thereby reducing overhead on the distribution routers.

This solution adheres to CCDE v3.1 design principles for:

Optimizing control plane scalability

Reducing unnecessary CPU load from control protocols

Ensuring a maintainable and scalable enterprise BGP deployment

Why the other options are incorrect:

BandD(Increasing memory): Addresses only hardware capacity without solving the root cause (BGP scaling issue).

C(Using eBGP): Misaligned with enterprise internal network design; eBGP adds complexity in route policy and administrative boundaries.

E(Increasing bandwidth): Bandwidth does not alleviate CPU overhead caused by BGP processing.

Implementing route reflectors aligns with both scalability and cost-efficiency goals as prescribed in the CCDE v3.1 methodology.

UplinkFast is an STP optimization feature designed primarily for access layer switches to reduce convergence time when a direct link failure occurs. When a primary uplink fails, UplinkFast immediately activates a backup uplink port without waiting for traditional STP convergence.

It is most effective on access layer switches where redundant uplinks to distribution switches exist.

On distribution switches, it may also be useful if they have multiple uplinks toward the core.

UplinkFast is not recommended for core switches as these typically don’t have redundant uplinks toward lower-tier devices.

It is not designed to resolve interoperability issues between different STP versions or to adjust hello timers.

—

In IoT environments, especially in manufacturing plants, security is the primary concern during migration:

IoT devices often have limited security capabilities and may introduce vulnerabilities if not properly segmented, authenticated, and monitored.

Manufacturing plants operate critical systems where availability, safety, and integrity are paramount.

CCDE v3.1 emphasizes securing data, devices, and control systems as a top priority during IoT migrations.

Other options explained:

A: Sensors are part of the IoT solution but not the primary migration concern.

C: Applications are important but typically come after securing connectivity and endpoints.

D/E: Infrastructure elements are secondary to security in the migration assessment.

—

Table Description automatically generated

HIPAA requires integrity controls to prevent unauthorized data modification.

D (Technical integrity and transmission security): Ensures PHI data is protected against unauthorized alteration during storage and transmission.

This directly addresses the issue of data being altered without consent.

Why other options are incorrect:

A: Prevents unauthorized access but does not guarantee data integrity.

B: Administrative processes cover policies, not technical enforcement.

C: Focuses on physical device control, not data integrity.

—

FCAPS stands for Fault, Configuration, Accounting, Performance, and Security.

D (Authentication) is not a management category within the FCAPS framework.

Authentication is part of security functions but not a standalone FCAPS category.

Why other options are correct FCAPS components:

A: Configuration management

B: Security management

C: Performance management

E: Fault management

—

C (Service orchestration platform):As branch scale increases, orchestration platforms automate multi-site deployment, configuration, and policy management. They integrate with controllers and external systems to reduce manual intervention, improve scalability, and enforce service consistency across thousands of locations.

Other options explained:

A: Management systems assist monitoring but don’t address provisioning complexity.

B: Lifecycle models guide processes but are not technical automation solutions.

D: Manual teams are not scalable for high-volume growth.

A: The overload bit (OL bit) signals other routers to avoid using the overloaded router as a transit path for Level 2 traffic. However, the overloaded router can still forward Level 1 local area traffic if applicable.

D: The overload bit is commonly used during router bootup to prevent temporary black holes while the router completes its routing protocol convergence and LSDB synchronization.

Why other options are incorrect:

B: CSNP prioritization is not related to overload bit functionality.

C: LSDB synchronization occurs through normal IS-IS mechanisms; overload bit is not involved.

E: The overload bit prevents transit usage, not attracts traffic.

A (Faster detection and response):Telemetry like IPFIX enables real-time network visibility and anomaly detection, significantly improving Mean Time to Detect (MTTD) and Mean Time to Respond (MTTR).

Other options explained:

B: IPFIX feeds data to incident response, but doesn't directly integrate plans.

C: IPFIX improves detection but primarily reduces response time.

D: Asset identification typically uses CMDB or inventory tools, not IPFIX alone.

A (Focus on the solution instead of the problem): While resolving issues quickly is important for operations, solution-oriented thinking during the design phase may overlook essential requirements analysis. Design decisions must be based on problem understanding, traffic analysis, and actual network behavior.

Other options explained:

B, C, D: All directly impact WAN design by influencing QoS, capacity planning, flow optimization, and visibility.

When multiple virtualized network zones (such as VRFs, virtual firewalls, or logical partitions) are consolidated onto a single physical device, the primary concern is:

A (Fate sharing): A single hardware failure, software crash, or resource exhaustion event could simultaneously impact all virtualized zones, creating a shared risk across multiple otherwise isolated services.

Other options explained:

B: CPU resource allocation can be controlled via resource management but is not the primary risk.

C: Congestion control is typically a traffic engineering issue, not a virtualization risk.

D: Security isolation can be maintained through proper virtualization boundaries.

E: Bandwidth can be managed through QoS and resource allocation.

—

In IPv6, routers advertise prefixes via Router Advertisement (RA) messages. An attacker could inject rogue RAs to manipulate the IPv6 configuration of endpoints.

Router Advertisement Guard (RA Guard) blocks unauthorized RA messages from being received on access ports, preventing endpoints from receiving incorrect IPv6 prefixes from malicious or misconfigured devices.

This security feature is crucial when devices have IPv6 enabled but the network is IPv4-only.

Other options explained:

A: Source Guard and Prefix Guard enforce valid address and prefix assignment but do not prevent RA spoofing directly.

C: Prefix Guard focuses on controlling prefixes being assigned, not blocking RA messages.

D: Secure Neighbor Discovery (SEND) provides cryptographic protection but is rarely deployed due to complexity.

Virtual Private LAN Service (VPLS) provides Layer 2 VPN connectivity over MPLS. Each Provider Edge (PE) device must learn and maintain MAC addresses per virtual instance.

PE Scalability is the primary concern: With 2000 VLANs, each PE participating in those instances must maintain a large forwarding table and handle associated control-plane activity.

MAC learning and aging, along with full-mesh label-switched paths (LSPs), place a heavy burden on CPU and memory.

Flooding (A) is expected but not the primary concern; it’s a symptom of scale.

The underlying transport (C) and VLAN ID limits (D) are important but not as critical in the context of PE resource scalability.

==========

Security design must be aligned with:

Business objectives (A): Security design must meet business needs without hindering operations.

Security policies and standards (B): Compliance with internal and external regulations is mandatory.

CCDE v3.1 teaches that security design always starts from business intent and policy compliance, not purely technical or scope-based factors.

Why other options are incorrect:

C & D: Security design applies to all environments, not just multi-site or new deployments.

—

The SDN architecture separates the control plane from the data plane. In this model, the SDN controller is the central element responsible for:

Receiving application intent via northbound APIs

Translating intent into traffic policies

Communicating with infrastructure devices using southbound APIs

The SDN controller enforces policies such as path selection, QoS, and access control rules across the network fabric, ensuring traffic flows align with administrator-defined logic. Neither northbound nor southbound APIs enforce policy themselves; they serve as communication interfaces.

The packet forwarding engine (Option A) simply performs data-plane functions based on instructions, but does not interpret or apply policies.

==========

B (Encrypt data when it is at rest and in motion): In hybrid cloud deployments, encryption is one of the most critical mechanisms to protect sensitive enterprise data both during storage (at rest) and while being transmitted (in motion). This ensures confidentiality and integrity across both private and public cloud environments.

Other options explained:

A: Using standard protocols is a general best practice but insufficient without encryption.

C: Communication of risks is part of compliance but does not enforce technical security.

D: Using standard protocols without encryption exposes data to risks.

—

A picture containing table Description automatically generated

IPv4:

Host Registration - IGMP

Router Registration - PIM-DM, PIM-SM, SSM, BIDIR

Inter-Domain Source Discovery - MSDP

IPv6:

Host Registration - MLD

Router Registration - PIM-SM, SSM, BIDIR

The goal is to prevent AS 111 from being used as a transit AS.

The most effective method is to use an AS path access list to filter outbound BGP advertisements, allowing only prefixes originated from AS 111 (AS path contains only AS 111).

This ensures AS 111 only advertises its own prefixes and does not forward third-party prefixes between providers.

Why other options are incorrect:

A: AS-set is used for aggregation, not for transit prevention.

B: Local preference controls outbound path selection, not advertisement or transit.

D: Prefix list on inbound filters received prefixes, but does not prevent transit.

—

Comprehensive and Detailed Explanation From Exact Extract of Design Expert (CCDE)

Summarization reduces control plane state by abstracting detailed route information. As packets move further away from the destination subnet, the network advertises summarized prefixes instead of individual host or subnet routes, minimizing control plane overhead and routing table size. This helps scale large networks and improves convergence times.

While aggregation and summarization are related, summarization specifically refers to the propagation of route prefixes and their abstraction — making it the precise fit for this question.

A (Distinguishing between config and operational data):NETCONF was designed to provide structured data models (such as YANG), clearly separating configuration from operational state data. SNMP lacks this built-in distinction and generally treats all data as MIB objects.

Other options explained:

B/C/D: Both protocols can perform actions and retrieve or modify data, but only NETCONF natively differentiates config vs. operational state.

D (Deploy SD-WAN edge routers in data center, then controllers, then branches):This allows the SD-WAN fabric to be built and stabilized centrally first, then controllers are brought online for policy orchestration, and finally, branch migrations happen gradually without impacting existing traffic paths.

Other options explained:

A/B/C: These approaches risk service disruption or poor controller orchestration readiness during branch migrations.

C (Untrusted VLAN): In out-of-band NAC Real-IP Gateway mode, unauthenticated clients are placed into the untrusted VLAN. The Clean Access Server handles traffic from these clients until authentication is complete.

Why other options are incorrect:

A: Authentication VLAN applies to some inline modes but not Real-IP Gateway.

B: User VLAN is assigned after successful authentication.

D: Management VLAN is used for administration, not for client onboarding.

—

C (Lack of visibility and tracking): In cloud-native environments, organizations often struggle with monitoring and tracking workloads across dynamic, distributed, and multi-tenant architectures. Traditional visibility tools may not fully cover cloud-native assets like containers, serverless functions, or microservices, making it harder to detect threats and enforce policies.

D (Increased attack surface): Cloud-native architectures introduce many additional components—APIs, microservices, third-party integrations, and distributed data—which all expand the organization's overall attack surface. More entry points for attackers create additional security challenges compared to traditional on-prem environments.

Other options explained:

A: User roles can be managed with proper IAM systems.

B: Polymorphism refers to code behavior in programming, not a core security challenge in cloud-native design.

E: Credential validation is part of basic access control but not a top cloud-native challenge compared to visibility and attack surface expansion.

B (Proactive network management):Network optimization involves ongoing monitoring, trend analysis, and proactive maintenance to prevent issues before they impact performance.

D (Network health maintenance):Optimization focuses on ensuring consistent network performance, reducing bottlenecks, and maintaining network integrity through regular health checks and adjustments.

Other options explained:

A: High availability is a design goal but not optimization itself.

C: Redesign suggests a major rearchitecture, not part of ongoing optimization.

E: Requirement identification happens during initial design phases.

In the Cisco three-layer hierarchical design model (Access, Distribution, Core), the access layer is primarily responsible for:

Providing user/device connectivity.

Enforcing policy boundaries.

Performing QoS classification and marking at ingress.

The access layer is the optimal point to classify and mark traffic for QoS because:

It is the first point of entry into the network for end-user devices.

Markings can then be trusted by upstream devices (distribution and core).

This minimizes trust boundaries throughout the network and ensures consistent policy enforcement.

This design principle ensures end-to-end QoS consistency, a key objective emphasized in CCDE v3.1 for scalable and maintainable enterprise designs.

Why other options are incorrect:

A (Fault isolation): Typically handled at distribution/core layers.

C (Reliability): A general network-wide requirement, not specific to access.

D (Fast transport): Primarily a core layer function.

E (Redundancy and load balancing): Managed primarily at distribution and core layers.

When an ACL is applied inbound on the Internet gateway interface facing the internal (trusted) network, the source IP address seen in the ACL will be the address after NAT translation has been applied to outbound traffic. This is called the inside global address:

Inside global = Public IP assigned by NAT to inside traffic for external use.

Inside local = Internal IP address prior to NAT.

Why other options are incorrect:

B, D: Outside addresses refer to external devices, not internal traffic.

C: Inside local is seen before NAT, not after.

—

D (Group Encrypted Transport VPN - GET VPN):GET VPN encrypts traffic across private WANs like MPLS while maintaining full-mesh routing visibility and offering centralized key management with minimal encapsulation overhead.

Other options explained:

A: S-VTI is used for point-to-point IPsec tunnels.

B: DMVPN is used for dynamic multipoint Internet-based VPNs.

C: MGRE is a tunneling protocol but lacks security features.

A modular, scalable network design aims to:

Localize faults

Reduce impact radius of failures

Enable automated fault detection and recovery

The primary operational driver is to reduce the need for manual intervention during failures, which translates to:

Faster recovery times

Consistency in troubleshooting

Improved service reliability

While minimizing app downtime (B) is a goal, it is a result of reducing human-required failure recovery. Option C is a business process goal, and D is an architectural challenge, not an operational driver.

This aligns with CCDE v3.1's “Network Architecture Principles” for building operationally resilient networks.

The question describes a network that requires virtualization at both control and data plane levels using VLANs and VRFs. This architecture aligns with:

Path isolation (A): Achieved using VRFs and VLANs, ensuring traffic separation at Layer 2 and Layer 3 across the entire network.

Group virtualization (C): Refers to grouping users or resources (such as departments or tenants) into isolated segments that remain logically separated throughout the campus fabric.

Other options explained:

B (Session isolation): More aligned with application or session-layer security, not data/control plane virtualization.

D (Services virtualization): Typically related to virtualizing network services (firewalls, load balancers).

E (Edge isolation): Not a standard design term in CCDE.

—

B (OTV — Overlay Transport Virtualization): Allows Layer 2 extension across data centers while maintaining fault isolation by not extending STP across the WAN. Control plane handles MAC learning, which provides stability and loop avoidance between data centers.

Why other options are incorrect:

A: FabricPath is mainly for intra-data center Layer 2 fabric.

C: Advanced VPLS extends Layer 2 but carries STP across the WAN.

D: LISP operates at Layer 3, not for Layer 2 extension.

E: TRILL also focuses on intra-DC Layer 2 but not DCI fault isolation.

—

STP Bridge Assuranceis a mechanism used to protect againstunidirectional link failureson point-to-point STP connections in environments likeRapid PVST+ and MST. When Bridge Assurance is enabled, BPDUs are expected on all BPDUs-capable interfaces. If a switch stops receiving BPDUs on a point-to-point link where Bridge Assurance is enabled, it assumes the link has failed and transitions the port to blocking to prevent a loop.

This is especially useful in high-availability enterprise designs that require protection from unexpected switch behavior or partial link failures.

Why other options are incorrect:

A. BPDU Guard: Protects access ports by placing them in an err-disabled state if BPDUs are received—useful at the edge, not for core loop protection.

C. MSTP: Refers to the protocol itself but does not solve the unidirectional link issue on its own.

D. TRILL: A different architecture (layer 2 routing) and not applicable to Rapid PVST+ or MST-specific protection.

SD-WAN design principles:

C: Centralized policy, simplified management, and dynamic path selection improve operational efficiency, directly resulting in cost savings.

D: SD-WAN provides centralized orchestration, automation, and zero-touch provisioning, simplifying deployment and scaling.

Why other options are incorrect:

A: SD-WAN improves performance with features like dynamic path selection but cannot inherently prevent slow underlay performance.

B: Many SD-WAN solutions logically separate control and data planes, but not all strictly follow full separation like traditional SDN.

E: SD-WAN is typically hardware-agnostic but does not depend on specialized switching hardware.

Unicast Reverse Path Forwarding (uRPF)is a security feature that helps mitigate IP spoofing attacks. It checks whether the source of a packet received on an interface matches the best return path to that source in the routing table.

Strict Mode (C):Ensures the source IP address of a packet is reachable via the same interface on which the packet was received. This prevents forged source IP addresses from traversing the network, which is essential in defending against outbound DDoS attacks sourced from infected hosts.

Loose Mode (B):Only verifies that the source IP exists in the routing table (less strict), which might still allow spoofing in multi-homed or asymmetric environments.

uRPF strict mode is the best fit in secure environments with symmetric routing—commonly in enterprise edge or distribution layers.

==========

The IoT ecosystem continues to evolve around industry-wide agreements on protocols, frameworks, security, interoperability, and standards:

D: Multiple IoT consortia (such as Industrial Internet Consortium, Open Connectivity Foundation, etc.) are still developing open frameworks and interoperability models.

E: IoT standards for security, data privacy, management, and protocol interoperability are still maturing as the market rapidly evolves.

Why other options are incorrect:

A: Wi-Fi protocols (such as 802.11ax) are already mature and standardized for IoT.

B: Regulatory domains (frequency allocations, power levels) are already well-established.

C: Low-energy Bluetooth sensors are already standardized and widely implemented.

—

C (Layer 2 switches unaffected):IPv6 operates at Layer 3, so pure Layer 2 switches forward frames without needing IPv6 awareness. As long as switches can transparently forward Ethernet frames, IPv6 functionality will be preserved, minimizing unnecessary hardware upgrades.

Other options explained:

A/B/D: These unnecessarily increase cost and complexity for basic Layer 2 functionality where IPv6 awareness is not mandatory.

For accurate location tracking in wireless networks, signal triangulation methods like RSSI, TDoA, or Angle of Arrival require:

A (Perimeter coverage): Adding APs along the perimeter improves location accuracy by minimizing blind spots and improving triangulation geometry.

B (Higher density, <40 ft spacing): Reducing inter-AP distance increases overlapping coverage, which provides more data points for accurate positioning.

Other options explained:

C: Directional antennas limit overlapping coverage, reducing triangulation accuracy.

D: Monitor mode APs can assist in location services but are secondary to proper placement and density.

E: Increasing transmit power may enlarge cell size but can decrease accuracy by reducing overlapping AP zones.

A (Jenkins):Jenkins is a leading Continuous Integration/Continuous Deployment (CI/CD) automation tool for building, testing, and deploying code automatically.

Other options explained:

B: Ansible is used for configuration management and automation.

C: Perl is a programming language, not a CI/CD platform.

D: Chef is a configuration management tool.

The primary goal of resilient modular network design is to minimize the operational impact of failures by automating recovery and isolating fault domains.

C: Reducing failures that require manual intervention improves availability, reduces downtime, and ensures stability even under fault conditions.

Why other options are incorrect:

A: This is a limitation to avoid, not a design driver.

B: Minimizing app downtime is an outcome, not the operational driver itself.

D: Development time is not related to operational network resiliency.

—

B: Service chaining in NFV can create suboptimal traffic flows depending on how virtualized functions are distributed.

E: NFV often requires orchestration platforms for lifecycle management, scaling, and automation of VNFs.

Why other options are incorrect:

A: Bandwidth utilization may not necessarily increase.

C: NFV enables use of commodity servers, not high-end routers.

D: OpenFlow is not mandatory for NFV deployment.

—

D: CWDM (Coarse Wavelength Division Multiplexing) shares parts of the same optical transmission window (1260–1625 nm) as DWDM but uses wider spacing between channels (typically 20 nm apart).

E: CWDM typically uses passive devices (multiplexers and demultiplexers) that require no electrical power, making deployment cost-effective.

Incorrect Options:

A: CWDM is better suited for shorter distances (up to ~80 km) and doesn't typically use optical amplifiers (EDFA). DWDM is better for long-haul with amplification.

B: 850 nm is used in multimode fiber systems (not CWDM).

C: CWDM supports up to 18 channels; DWDM supports up to 32 or more.

==========

Comprehensive and Detailed Explanation:

C: Moving workloads or backup/recovery functions to cloud platforms reduces capital expenditure by avoiding the cost of physical infrastructure, data centers, and maintenance. Cloud-based DRaaS (Disaster Recovery as a Service) offers scalability, resilience, and cost efficiency aligned with an OPEX model.

Other options:

A and B are security and software lifecycle tasks, not cost-effective DR strategies.

D increases CAPEX by building and maintaining additional infrastructure.

==========

B (Software as a Service - SaaS):SaaS provides end users with complete applications hosted and managed by third-party providers, accessed via web interfaces.

Other options explained:

A: PaaS provides platforms for application development, not complete applications.

C: IaaS provides compute/storage resources but not full applications.

D: WaaS (Workspace as a Service) is a niche model, not generally used as standard SaaS definition.

Increasing jitter buffer size smoothens jitter but at the cost of introducing additional delay.

Excessive jitter buffering can lead to perceptible audio or video lag, impacting user experience.

C: Therefore, the undesired effect is increased transport delay, potentially leading to quality issues if the buffer size is too large.

Why other options are incorrect:

A & D: Jitter buffering does not improve jitter itself; it masks it at the expense of delay.

B: Jitter compensation doesn't increase jitter, but delay.

—

Route Distinguishers (RDs) are fundamental to MPLS Layer 3 VPN architecture (RFC 4364). They allow the service provider to distinguish identical IP prefixes from different VPN customers by adding a unique identifier to each VPN route, preventing conflicts from overlapping IP spaces.

Unique RDs ensure that the VPNv4 address family maintains separation of identical customer prefixes.

Why other options are incorrect:

B: Route Targets control route import/export policy but do not differentiate overlapping prefixes.

C: NAT is not required inside MPLS VPN for overlapping IPs.

D: VRF IDs are local identifiers on routers; not relevant for prefix uniqueness in control plane.

—

A (Confidentiality): Protects information from unauthorized access.

D (Availability): Ensures resources are accessible when needed.

E (Integrity): Ensures data is not tampered with or altered improperly.

These three form the core of information security design principles known as the CIA triad (Confidentiality, Integrity, Availability), directly referenced in CCDE v3.1 security design sections.

Why other options are incorrect:

B, C, F: While important for network design, they are not part of the core security protection objectives.

—

A (PPDIOO - Prepare, Plan, Design, Implement, Operate, Optimize):PPDIOO is Cisco’s structured lifecycle methodology designed specifically for network design, deployment, and management. It ensures continuous improvement, iterative design, and aligns technical efforts with business goals throughout the entire network lifecycle.

Other options explained:

B: Waterfall is a generic software development methodology.

C: Spiral emphasizes iterative risk management for software development.

D: V model applies primarily to software verification and validation.

B (MST — Multiple Spanning Tree): Bundles multiple VLANs into fewer STP instances, minimizing the scope of TCN propagation, which helps reduce MAC table flushing and unicast flooding.

Why other options are incorrect:

A: PVRSTP still processes TCNs per VLAN, increasing flooding.

C: Legacy STP behaves similarly but is not optimized for multiple VLANs.

D: PVSTP+ generates TCNs per VLAN like PVRSTP.

—

A (SD-WAN):SDN principles are widely adopted in wide area networks for dynamic path selection, centralized control, and policy enforcement.

B (Mobile networks):5G and modern mobile networks leverage SDN/NFV architectures to virtualize core services and optimize resource utilization.

Other options explained:

C: Metro networks adopt SDN, but WAN and mobile are more common mainstream use cases.

D/E: Application and control network are not direct SDN network types.

Comprehensive and Detailed Explanation From Exact Extract of Design Expert (CCDE)

Controller-based networks centralize control logic, abstracting hardware complexity and providing consistency. This results in:

C. Abstraction: Devices are treated as policy endpoints rather than configuration silos, simplifying network operations and scalability.

E. Consistent Configuration: Policies and configurations are pushed uniformly across all devices from the controller, reducing human error and improving compliance.

These features align with CCDE v3.1 recommendations for modern, policy-driven, and scalable architectures that are easier to manage and automate.

==========

B (Strategic planning): Long-term business-aligned decisions that shape future infrastructure needs.

D (Tactical planning): Short-to-mid-term activities that adjust design based on evolving operational realities, constraints, and priorities.

Why other options are incorrect:

A & E: While cost and business optimization are goals, they are not defined planning approaches.

C: Modular is a design methodology, not a planning approach.

—

B (Install firewalls):PCI DSS requires network segmentation, filtering, and perimeter defense via firewalls.

C (Use antivirus software):Malware protection and anti-virus software are mandatory on all systems interacting with cardholder data.

Other options explained:

A/D/E: These are general security best practices but not specific mandatory requirements under PCI DSS control objectives.

In this scenario, the application itself duplicates data transmission across two separate NICs on Host A, with the intention that at least one copy will reach Host B, regardless of any single path or link failure. While this increases redundancy at the application and host level, the underlying network must also support rapid failure recovery to avoid packet loss during convergence events.

Among the options provided:

A. EIGRP with feasible successors provides pre-computed backup routes but still requires routing protocol convergence upon failure, which could result in millisecond-scale interruption—enough to cause data loss if packets are in transit.

B. BFD (Bidirectional Forwarding Detection) offers rapid detection of link failures, but by itself does not provide traffic redirection or packet protection; it simply informs the routing protocol faster.

D. Static routes lack dynamic convergence capabilities and would not offer high availability across dynamic failure points unless manually configured with tracking—still less responsive and scalable.

C. IP Fast Reroute (IP FRR) is specifically designed to offer sub-50ms convergence time by pre-installing backup paths in the forwarding plane. Upon detecting a failure, traffic is immediately switched to the pre-computed alternate path without waiting for the routing protocol to reconverge. This ensures minimal disruption and best supports lossless delivery for high-availability applications.

IP FRR is consistent with CCDE v3.1 design principles where sub-second convergence and resiliency are critical in mission-critical enterprise and data center architectures.

C (Class-Based Weighted Fair Queuing - CBWFQ): CBWFQ allows assigning bandwidth limits (in this case, 2 Mbps) to specific traffic classes, effectively controlling scavenger traffic without dropping excess packets unnecessarily.

Other options explained:

A: Policing drops excess traffic immediately rather than queuing.

B: LLQ is for delay-sensitive traffic, not scavenger control.

D: Shaping is useful but typically applied at interface level, not specific traffic classes.

C (Complex and distributed management flow):SDN centralizes control-plane management, simplifying complex, distributed configuration and operational models, which is especially valuable in large-scale, dynamic cloud environments.

Other options explained:

A: SDN may assist, but intelligent monitoring is a separate operational task.

B: SDN does not directly address resource growth—it supports scalability but doesn’t limit application resource demands.

D: SDN may reduce OpEx, but the primary benefit is operational simplification rather than direct cost reduction.

==========

Inbound traffic engineering is best controlled by manipulating how external ASes view your routes.

AS path prepending on the 91.7.0.0/16 prefix towards AS 200 makes AS 500 prefer the less-prepended path through AS 100.

This allows granular inbound control for that specific prefix while leaving the rest of the traffic unchanged.

Why other options are incorrect:

B: Extended community is not used for direct inbound path manipulation.

C: Local preference affects outbound traffic, not inbound path selection by remote ASes.

D: MED is only compared between the same AS; it won't affect AS 500's choice.

—

The scenario prioritizes:

In-house management (not managed services)

Scalability (exponential branch growth)

OPEX reduction (low operational cost)

SD-WAN over L3VPN offers a balance of:

Mid-level ISP cost (leveraging L3VPN as transport)

Centralized management and automation (ZTP, templates)

Support for segmentation, application-aware routing, and path control

Lower OPEX due to simplified configuration and monitoring

Managed SD-WAN has higher ISP and OPEX cost, and DMVPN is more manual and complex to scale. SD-WAN over L2VPN might reduce ISP cost but is less common and not optimal for rapid scalability.

B (OSPF Type 1 external):Type 1 external routes include both the external cost (from redistribution) and the internal OSPF cost to the ASBR. This ensures accurate end-to-end metric calculation across domains.

Other options explained:

A: Type 2 external ignores internal OSPF cost, potentially creating suboptimal routing.

C/D: EIGRP doesn’t use OSPF metric types; redistribution into EIGRP uses EIGRP metrics.

NETCONF (Network Configuration Protocol) is a standardized protocol used for automating configuration and management of network devices. According to IETF standards (RFC 6241), the required encoding for NETCONF is:

XML (Extensible Markup Language)

Cisco IOS XE supports NETCONF over SSH and uses XML to structure both configuration data and RPC messages. XML allows strict schema validation (via YANG models), extensibility, and rich hierarchical structure required for modern network automation.

Other formats:

HTML is not a data encoding method.

YAML is typically used with configuration management tools, not NETCONF.

JSON is supported in RESTCONF, not in traditional NETCONF.

==========

A: FabricPath assigns a specific multicast (S,G) flow to one tree. A single (S,G) does not get load-balanced across multiple trees.

E: Overall multicast traffic across multiple (S,G) groups is distributed across multiple FabricPath trees, providing general load balancing and efficient link utilization across the fabric.

Why other options are incorrect:

B: Traffic load per tree may not be uniform due to different group distributions.

C: The assignment is done by the ingress switch based on hashing, not all leaf nodes assign the same tree.

D: Individual (S,G) flows do not get load-balanced across trees.

—

Graphical user interface Description automatically generated with medium confidence

B: In transparent mode, the firewall operates at Layer 2 and can participate in STP to avoid loops.

C: Multicast traffic can traverse the firewall if allowed through transparent bridging rules.

Why other options are incorrect:

A: Transparent mode requires no change to IP addressing.

D: Transparent firewalls do not form routing adjacencies.

E: Routed mode firewalls operate at Layer 3; transparent mode does not insert router hops.

—

A (BPDU Guard on access ports): Prevents accidental connection of switches or bridging devices on access ports, which could cause unexpected topology changes or loops.

C (Root Guard on aggregation switch downlinks): Ensures access switches cannot send superior BPDUs to challenge aggregation switch root status, maintaining predictable STP root placement.

Why other options are incorrect:

B: Aggregation downlinks are not normally configured with BPDU Guard (since they expect BPDUs from access switches).

D: Root guard on access ports is unnecessary as those ports should not participate in STP.

E: Edge port (Rapid STP concept) is good for faster convergence but doesn't address stability.

F: STP root and backup root election is important but not a specific STP feature — this is a design decision, not a stability feature.

PortFast is a feature that allows access ports to enter the STP forwarding state immediately, without waiting for the usual listening and learning states. This accelerates the connection of end devices like PCs or servers.

A key design benefit is that PortFastdoes not trigger topology changeswhen devices are plugged in or disconnected. This prevents unnecessary STP recalculations and protects core stability.

Correct Statement (A):STP does not consider link transitions on PortFast-enabled ports as topology changes, reducing control-plane overhead.

Other options misrepresent the function of PortFast:

B:PortFast does not disable STP; it bypasses specific STP states.

C/D/E/F:These describe other features like Loop Guard or UDLD, not PortFast.

==========

D: Traditional three-tier architectures (access, distribution, and core layers) require that east-west traffic (between servers or pods in different access layers) traverse up to the distribution or core and then back down—introducing unnecessary hops and latency. This is a key design limitation addressed by spine-leaf and fabric architectures.

Other options:

A: Bandwidth may be sufficient but not optimally utilized due to suboptimal pathing.

B: Security is not inherently compromised by architecture, although microsegmentation is harder.

C: Three-tier architectures can scale, but less efficiently and not without trade-offs like latency and complexity.

==========

For EIGRP to maintain loop-free alternate paths, the feasibility condition must be met:

A. The Reported Distance (RD) must be lower than the router's Feasible Distance (FD).

E. A feasible successor must exist (i.e., an alternate next-hop satisfying the feasibility condition).

This design allows immediate failover without recomputation, ensuring fast convergence — a critical CCDE v3.1 protocol design principle.

Why other options are incorrect:

B, C, D: Misstate the feasibility condition or confuse RD and FD relationships.

—

Agile project management supports:

Frequent updates and iterative feedback loops

Flexibility to accommodate evolving requirements

Continuous customer collaboration and transparency

This methodology is ideal for projects where scope may shift and customer involvement is essential. In contrast:

Waterfall is linear and rigid

Phased delivery segments milestones but limits change midstream

“Three principles” is not a recognized methodology in this context

Agile aligns with modern IT deployment models and is supported in CCDE methodology as a business-aligned and adaptive design execution strategy.

B (R1 adjusts to R2’s Required Min RX):In BFD, each side advertises itsDesired Min TX IntervalandRequired Min RX Interval. Each device adjusts its transmission interval to match the remote side’s ability to receive packets (Required Min RX). So R1 reduces its transmission rate to 100 ms to match R2's platform limitations.

Other options explained:

A: R2 does not adjust to R1’s Desired Min TX; it’s the sender who adapts.

C: BFD quickly converges after initial negotiation.

D: P-bit and F-bit are not involved in this specific interval negotiation.

When both networks use overlapping private IP addresses, a single Cisco IOS NAT router can handle bidirectional NAT with dynamic NAT (overload). However, it requires careful configuration using:

Two distinct NAT pools: One for traffic sourced from side A, and one for traffic sourced from side B.

ip nat inside source and ip nat outside source commands with the overload keyword.

Interfaces must be properly defined with ip nat inside and ip nat outside to reflect traffic directionality.

Option D is correct because it explicitly reflects the requirement to use two different NAT pools for overload in both directions, which ensures proper address translation and session tracking.

==========

To support high-bandwidth, low-latency Layer 2 communication between DB Server 1 and DB Server 2, you must create a direct Layer 2 path between SW1 and SW2. Using REP (Resilient Ethernet Protocol) segments ensures loop-free Layer 2 operation without the drawbacks of STP convergence delays.

Option C is correct: Adding a third REP segment (Segment 3) directly between SW1 and SW2 isolates the traffic between the two DB servers and ensures deterministic behavior with fast convergence.

Option A (LACP with STP) introduces STP blocking and doesn’t align well with REP's control plane.

Option B and D: Overloading existing segments or splitting new links into existing REP segments does not offer the same direct path, bandwidth, or deterministic behavior.

==========

A (TRILL - Transparent Interconnection of Lots of Links):TRILL enables multipathing at Layer 2, eliminating classic STP blocking, allowing all uplinks to be active simultaneously, and uses IS-IS based control plane for conversational MAC learning.

Other options explained:

B: LISP operates at Layer 3 for endpoint mobility, not Layer 2 multipathing.

C: MSTP still blocks some links under normal operation.

D: Switch stacking merges multiple physical switches into one logical switch but does not provide true multipathing across independent switches.

D (Data confidentiality rules): The most critical factor in cloud service placement is data confidentiality and compliance with regulatory requirements. Certain data may not legally or contractually be permitted to leave specific geographic or organizational boundaries, directly influencing whether a public, private, hybrid, or on-premise deployment is used.

Other options explained:

A: Replication cost is important but secondary to legal and regulatory compliance.

B: Application structure affects architecture but doesn't override confidentiality restrictions.

C: Implementation time is a project management concern, not a service placement driver.

—

B (Platform as a Service – PaaS): In a PaaS model, the cloud provider manages the operating system, middleware, runtime, and platform stack. The customer is only responsible for deploying and managing the application itself.

This abstraction allows developers to focus on application logic without worrying about the infrastructure or platform details.

Other options explained:

A (IaaS): Customer manages OS, middleware, and runtime; provider manages hardware and virtualization.

C (SaaS): Customer simply consumes the application; all layers are managed by the provider.

D (BMaaS): Bare Metal as a Service — customer has full control over hardware and all software layers.

—