Pass the Cisco CCDE v3.0 400-007 Questions and answers with CertsForce

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.

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B (Dynamic real-time change):SDN must adapt dynamically as network demands and application requirements evolve.

E (Integration of device context):Understanding device-level status, capabilities, and resource availability allows controllers to make informed decisions, reducing visibility gaps.

Other options explained:

A: On-demand growth is a business benefit but not related to visibility/performance gaps.

C: Reverting to legacy behaviors undermines SDN benefits.

D: Peer-to-peer controllers help scale, but not directly tied to visibility gaps.

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.

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C (More consistent device configuration):Centralized control allows uniform policy application, eliminating configuration drift across devices.

E (Configure features at network-level rather than device-level):Controller-based networks abstract network services from individual devices, enabling network-wide configuration from a single source of truth.

Other options explained:

A: Forwarding tables still exist in both architectures.

B: Traditional networks offer per-device flexibility; controllers abstract this.

D: APIs are usually provided at controller level, not per device.

B (East-West API between controllers):In multicontroller SDN architectures, East-West APIs allow controllers to synchronize state, policies, and tasks, enabling distributed control while presenting a unified control plane view. This ensures that tasks can be performed on any controller consistently.

Other options explained:

A: Root controllers are not standard in modern SDN distributed architectures.

C: Physical connectivity alone doesn't synchronize state or tasks.

D: OpenFlow governs switch forwarding, not controller-to-controller interaction.

ChatGPT said:???? QUESTION NO: 391

[Main Topic: Scenario-Based Design Strategy Guidance]

Feature-rich and attributed networks are used to model complex systems where nodes and links can represent various relationships and characteristics. Which two alternative network models can be used to model interactions over time or by specific relationships?

A. heterogeneous network

B. information network

C. location-aware network

D. multilayer network

E. probabilistic network

F. temporal network

Answer: D, F

????Comprehensive Explanation:

D. Multilayer Network:This model captures different types of relationships or interactions by separating them into layers. Each layer can represent a specific attribute (e.g., organizational structure, communication paths, or access levels), enabling a more granular view of network behaviors or dependencies.

F. Temporal Network:A temporal network models interactions over time by including timestamps or time intervals for each interaction or link. It’s well-suited for analyzing dynamic behaviors such as traffic flow, communication logs, or transaction timelines.

Other options:

❌A. Heterogeneous Network: Refers to networks composed of different technologies or platforms, not necessarily different types of attributes or timelines.

❌B. Information Network: This is a general term and does not specifically define a structured modeling approach for attributes or time.

❌C. Location-Aware Network: Involves geolocation or spatial data but does not inherently model time or multi-attribute structures.

❌E. Probabilistic Network: Uses probability distributions to model uncertain events, not ideal for modeling time or attributes.

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???? QUESTION NO: 392

[Main Topic: Business-Driven Design Approaches]

A company is assessing their technology landscape before moving to the cloud. They observe that over 5000 servers have less than 50% capacity utilization. What cloud architecture model best supports optimizing resource utilization?

A. homogenous cloud

B. heterogenous cloud

C. hybrid-private cloud

D. public cloud

Answer: D

????Comprehensive Explanation:

D. Public Cloud:Public cloud services provide elastic and scalable infrastructure. For workloads with low or variable utilization, public cloud offers pay-as-you-go models that significantly reduce the overhead of underutilized on-prem hardware. This is ideal for shifting capital expenditure (CAPEX) to operational expenditure (OPEX), achieving better cost efficiency.

Other options:

❌A. Homogenous Cloud: Not a standard term; it might imply uniform hardware/software environments, but it doesn’t address utilization.

❌B. Heterogenous Cloud: Typically used to describe mixed environments but doesn’t directly offer utilization optimization.

❌C. Hybrid-Private Cloud: Offers flexibility and data control but still often involves maintaining some level of underused on-prem resources unless carefully managed.

????Explanation:

B: To prefer ISP 1 for outbound traffic, advertise a longer AS path to ISP 2 (so it's used as backup). To prefer ISP 1 for inbound traffic, you want ISP 2 to receive a higher MED, making it less preferred. These changes signal to both ISPs and remote ASes to prioritize the ISP 1 path.

Other options:

A: Local preference is set inbound by your own routers, not outbound to ISPs.

C: Local preference affects only your own AS, and more specific routes are better advertised on primary links, not secondary.

D: Advertising less specific routes does not help establish control over preference cleanly.

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???? QUESTION NO: 387 [Security, Automation, and Policy Integration in Design]

Which three components support enforcing security policy compliance for devices attempting network access? (Choose three)

A. Posture agent

B. Audit and decision point servers

C. Management and reporting tools

D. Endpoint security application

E. Network access devices

F. Web filtering devices

Answer: A, B, E

????Explanation:

A: Posture agents assess the health of endpoints (e.g., antivirus status, OS patching).

B: Decision servers (e.g., Cisco ISE) enforce access decisions based on posture and policies.

E: Network access devices (e.g., switches, WLCs, routers) apply access controls based on server instructions (802.1X, NAC).

Other options:

C: Management tools are for visibility—not enforcement.

D: While useful, endpoint AV/firewalls act independently—not part of policy enforcement infrastructure.

F: Web filters do not participate in initial access decisions.

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???? QUESTION NO: 388 [Security, Automation, and Policy Integration in Design]

When are Network Behavior Anomaly Detection (NBAD) systems better than signature-based systems? (Choose two)

A. Malware detection

B. Encrypted threat traffic

C. Spyware detection

D. Intrusion threat detection

E. New zero-day attacks

Answer: B, E

????Explanation:

B: Signature-based systems cannot inspect encrypted payloads effectively, whereas NBAD relies on traffic behavior.

E: NBAD identifies deviations from known good behavior, allowing detection of previously unknown (zero-day) threats.

Incorrect Options:

A, C, D: These are often more accurately detected using signature-based approaches where known

????QUESTION NO: 389

[Main Topic: Security, Automation, and Policy Integration in Design]

A company is adopting IPv6 in a dual-stack campus network. The first IPv6-only application is now hosted in the data center. To prevent a malicious user from masquerading as the IPv6 default gateway, which two mechanisms should be used? (Choose two)

A. IPv6 RA guard

B. IPv6 snooping

C. IPv6 device tracking

D. IPv6 address glean

E. port ACLs

Answer: A, E

????Comprehensive and Detailed Explanation (CCDE v3.1 aligned):

A. IPv6 RA Guard:This feature helps mitigate rogue router advertisements (RAs), which attackers can use to spoof the default gateway in an IPv6 environment. RA Guard drops unauthorized or unexpected RAs at the access layer switch ports, preventing malicious devices from advertising themselves as routers.

E. Port ACLs (PACLs):Port-based ACLs can restrict which devices are allowed to send or receive RA packets on switch ports. By tightly controlling which sources can send traffic (including RA messages), port ACLs help prevent spoofing attempts.

Other Options:

❌B. IPv6 Snooping:Not a standard or widely supported security feature; it is sometimes used synonymously with device tracking but is not a direct mitigation for spoofed RAs.

❌C. IPv6 Device Tracking:Useful for monitoring IP-to-MAC bindings, but it does not prevent spoofing or gateway impersonation.

❌D. IPv6 Address Glean:Primarily used for learning IPv6 addresses from traffic for things like DHCPv6 relay; not a security feature.

CCDE Blueprint Alignment:

Topic: Security, automation, and policy integration in design

Subdomain: IPv6 security, access control, rogue device prevention.

Let me know if you'd like the next question explained!

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.

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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.

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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.

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