400-007 Exam Dumps - Cisco CCDE v3.0 Questions and Answers

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.

When logical VRF separation is based on fields like IP address ranges or packet characteristics (such as packet length), the most scalable solution is:

Policy-Based Routing (PBR): This allows traffic to be classified and forwarded into the correct VRF based on flexible match conditions like source IP address, destination IP address, or packet size.

Why other options are incorrect:

A: Static route leaking lacks flexibility and scalability for dynamic classification.

C: OSPF per VRF handles control-plane separation, but not data-plane traffic classification.

D: MP-BGP is used for control-plane VPN route exchange, but not for VRF selection based on traffic attributes.

—

Cloud Bursting is the process by which applications or workloads that run in a private cloud or data center environment are "bursted" into a public cloud infrastructure during high-demand periods. This prevents service degradation and ensures performance continuity without manual intervention.

In CCDE design strategy terms, this enables:

Elastic scalability

Cost-effective use of public infrastructure on-demand

Seamless service delivery to end users

Options like “cloud policing” and “cloud shaping” are not standard terms, and “cloud spill” is not an established mechanism. “Cloud bursting” is the correct architectural mechanism that addresses this overflow requirement.

==========

B: In dual cloud DMVPN designs, hubs typically terminate both clouds to provide full resiliency.

C: The design improves high availability and redundancy in case one DMVPN cloud fails.

Why other options are incorrect:

A: Multi-tier (multi-hub) architectures are supported.

D: Spoke-to-spoke communication can be direct via NHRP once the overlay is established; it doesn’t have to always transit hubs.

E: Dual Internet connections are not strictly required for dual cloud DMVPN — dual tunnels can be built even with a single Internet connection.

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.

==========

Reducing BGP keepalive and hold timers can help improve convergence but must be done carefully in provider-managed networks:

A: The service provider must agree to support modified timers on both PE and CE; otherwise, mismatched timer settings can break neighbor relationships.

C: The service provider may need to schedule configuration changes on PE routers to synchronize the timer adjustments and avoid service interruptions.

Why other options are incorrect:

B: Peer groups simplify policy application but do not impact BGP timers directly.

D: The number of routes affects convergence processing but not directly tied to timer adjustment.

E: The number of VRFs is a scalability consideration but unrelated to BGP timer negotiation.

—

When Bidirectional Forwarding Detection (BFD) is not available, OSPF can still achieve subsecond convergence using the OSPF fast hello feature.

Fast hello allows the configuration of OSPF hello/dead intervals to subsecond values (e.g., hello = 100ms, dead = 300ms).

This accelerates OSPF’s ability to detect neighbor failures based on missed hello packets without relying on external mechanisms like BFD.

Why other options are incorrect:

A. STP (Spanning Tree Protocol) is unrelated to OSPF and is used at Layer 2.

C. LFA (Loop-Free Alternate) is a fast reroute technique but does not affect neighbor failure detection.

D. DPD (Dead Peer Detection) is used in VPN technologies (e.g., IPsec) and not applicable in OSPF.

Fast hello is fully aligned with CCDE v3.1 under “Protocol Design Implications” and is a commonly recommended method for improving IGP convergence performance when BFD is not an option.

==========

D (Enables innovation):SDN allows new services, business models, and automation capabilities.

E (OpEx/CapEx reduction):Automation reduces operational effort, and commodity hardware reduces CapEx.

Other options explained:

A: Redundancy depends on physical design.

B: SDN centralizes management.

C/F: SDN doesn't directly impact latency or capacity.

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.

—

Comprehensive and Detailed Explanation:

D: The most effective solution is to have Site-X advertise a more specific (longer) prefix (e.g., 100.75.10.0/24), which allows external BGP routers to prefer Site-X over Site-Y. This ensures traffic destined for Site-X flows directly to it, preserving symmetry. Additionally, control plane coordination between R1 and R2 ensures proper routing consistency and minimizes the risk of loops or misdirection.

Other options:

A: Using BGP MED works within the same AS; it is often ignored by external ISPs.

B: Replicating firewall behavior does not address the routing issue.

C: DNS manipulation is a workaround—not a scalable or robust design solution.

This solution is consistent with BGP best practices and CCDE v3.1 guidance on traffic engineering and policy-based routing.