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

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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.

In OSPF multi-area designs with multiple ABRs, when there is temporary inconsistency between the ABRs’ type-3 summary LSAs, microloops can occur during convergence. These loops happen due to slight differences in LSA arrival and SPF calculations across routers while the network is converging.

Microloops are short-lived but can cause brief packet loss.

This becomes more likely as the number of ABRs grows and IGP flooding domains increase.

CCDE v3.1 emphasizes careful ABR design and possible use of loop avoidance mechanisms (e.g., LFA, microloop prevention techniques) in large-scale OSPF designs.

Why other options are incorrect:

A: LSA flooding in OSPF scales well; type-3 LSA replication is not the primary scalability issue.

B: ABRs process all LSAs regardless; load is not split.

D: Multiple ABRs all independently summarize and advertise into the backbone.

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Traffic shaping buffers excess traffic and smooths traffic bursts, which is essential for DaaS traffic sensitive to periodic link congestion across WAN circuits.

It helps ensure consistent, predictable performance under fluctuating WAN conditions.

Why other options are incorrect:

A: Tail drop leads to congestion and packet loss.

C: WRED is used for congestion avoidance, but not ideal for real-time DaaS traffic shaping.

D: Policing drops excess traffic instead of buffering, worsening DaaS disconnections.

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.

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Comprehensive and Detailed Explanation:

B: Modular network design allows the network to be broken into independent functional units (modules) such as access, distribution, data center, WAN, and edge. When divesting part of a business, modularity allows specific segments (like a business unit or site) to be isolated and removed with minimal impact on other components.

Other options:

A (Redundant design): Enhances high availability but doesn't address separation or detachment flexibility.

C (Less complex design): While simpler, it may not provide the isolation necessary to enable selective detachment.

D (Routed access): Refers to Layer 3 access layer designs, useful in access control but not focused on business separation scenarios.

A (EIGRP summarization):Summarization reduces unnecessary routing information exchange, simplifies the routing table, and improves convergence.

D (Route leaking on London-Rome link):Route leaking allows specific prefixes (such as important routes for direct communication) to be advertised across the London-Rome link, ensuring it's utilized where appropriate.

Other options explained:

B: Filtering routes on Barcelona would prevent reachability unnecessarily.

C: Filtering on London-Rome link would prevent its usage entirely.

IPFIX probes can perform deep flow inspection beyond what routers/switches natively collect, making them well suited for security monitoring (DDoS detection, anomaly detection, intrusion attempts).

Probes can extract Layer 7 information unavailable from normal router flow records.

Why other options are incorrect:

A, C, D: Can also be done using router-integrated flow exports; dedicated probes are primarily deployed for advanced security visibility.

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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.

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C (Push-based):Push notifications to a registered device (typically a phone) are used as a second authentication factor.

D (Possession-based):Possession factor includes physical tokens, smart cards, or registered devices — verifying that the user possesses something unique.

Other options explained:

A/B/E: Not valid MFA factors under standard authentication frameworks.

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