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

SNMPv3 is recommended as it supports authentication and encryption, protecting SNMP traffic even across service provider MPLS VPN backbones.

Healthcare environments require strong privacy and compliance (e.g., HIPAA), making SNMPv3 the correct protocol.

Why other options are incorrect:

B & C: Syslog is unrelated to SNMP traps.

D: SNMPv2 lacks security (unencrypted community strings).

E: SSH secures CLI access but not SNMP.

B (Separate priority queues): Both VoIP and the custom stock-trading application require low latency and jitter guarantees but serve different business functions. Best practice is to place them in separate priority queues to prevent one application's bursts from affecting the other, ensuring deterministic service levels for both mission-critical services.

Other options explained:

A: Sharing queues may lead to competition between traffic types, risking SLA violations.

C/D: CBWFQ is not sufficient for true low-latency guarantees; priority queuing is required.

—

A soft failure refers to a condition where the network continues to operate, but performance or behavior is degraded in a way that is not immediately visible or detectable—this includes suboptimal routing, misconfigured protocols, or resource inefficiencies. These are harder to define and detect because they don't cause total outages but still impact user experience or service quality. In contrast, hard failures like outages (Option D) are more visible and measurable.

This aligns with CCDE v3.1’s guidance on resilience, observability, and performance-aware design, emphasizing proactive identification of non-fatal but service-impacting anomalies.

==========

B (Added redundancy): Redundancy ensures alternate paths or systems are available if a failure occurs, which is the primary design principle behind resiliency. Redundancy directly contributes to higher network availability and fault tolerance.

Why other options are incorrect:

A: Load-balancing optimizes performance but doesn’t inherently improve resiliency.

C: Confidentiality addresses security, not resiliency.

D: Reliability is an outcome, not a design principle itself.

—

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.

A (Design expecting outages and attacks):In WAN design, resiliency requires assuming that failures and attacks will occur. This drives the use of redundancy, diverse paths, and proactive failure mitigation techniques.

Other options explained:

B/C/D: While important, these focus on operational efficiency rather than core resiliency principles.

B: Faster control plane convergence reduces the total recovery time after failure detection.

D: Enabling lower layer detection (such as BFD or physical layer link failure detection) shortens the time it takes to notify the control plane about link failure.

Why other options are incorrect:

A: Stability improves network operation but doesn’t address detection delay directly.

C: Interface flaps notification frequency doesn’t reduce initial detection delay — could actually create instability.

—

C (QoS policy propagation with BGP - QPPB):Allows QoS policies to be dynamically applied based on BGP routing information, integrating policy control into routing decisions.

D (Remote black-holing trigger):Enables dynamic mitigation of attacks (e.g., DDoS) by injecting blackhole routes through BGP to selectively drop malicious traffic upstream.

Other options explained:

A/B/E: Static policy mechanisms that lack dynamic flexibility and responsiveness in modern service provider designs.

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.

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.