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

EIGRP may be valid for initial deployment, but its scalability limitations — including proprietary nature, limited support over non-broadcast multipoint VPNs, and suboptimal convergence for large WAN overlays — make it most restrictive for future expansion.

BGP is typically the most scalable choice for large-scale VPN WAN deployments.

Why other options are incorrect:

B: IS-IS is not commonly deployed over Internet VPNs.

C: OSPF has better scalability than EIGRP for multi-area design but still limited over VPN overlays.

D: BGP is the preferred protocol for large-scale IPsec VPN WANs.

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B (Segment Routing): Allows traffic engineering and micro-segmentation across networks by steering traffic based on policies and labels.

D (Firewalls): Provide Layer 4-7 segmentation and security enforcement between segments.

Why other options are incorrect:

A: Policy-based routing influences forwarding, but is not a segmentation technology.

C: Data plane markings support QoS but do not create segmentation boundaries.

E: Filter lists are used in routing policy, not for full network segmentation.

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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.

The core issue is excessive SPF recalculations in Area 5 caused by too many specific LSAs being flooded into the area. The most effective solution is to use LSA filtering and summarization on the ABR to limit the number of detailed LSAs advertised into Area 5. This reduces SPF computation load while improving stability without requiring changes on Router B (which cannot support stub area).

Why other options are incorrect:

A: Bandwidth increase does not prevent SPF recalculations.

C: Virtual links wouldn’t change LSA flooding into Area 5.

D: LSA throttling limits frequency but not volume of recalculations.

E: Stub area configuration requires support from all routers in the area, which Router B does not provide.

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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.

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A (MSDP - Multicast Source Discovery Protocol):MSDP allows different autonomous systems to share multicast source information while maintaining their own PIM Sparse Mode domains. It simplifies interdomain multicast routing without requiring full mesh peering or shared RPs between domains.

Other options explained:

B: SSM does not require MSDP but limits use to source-specific groups.

C: MPLS is a transport technology, not multicast control-plane solution.

D: PIM-SM is used within a domain, not across multiple autonomous systems.

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.

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A (Encryption + strong authentication) aligns most closely with Zero Trust’s emphasis on always verifying identity and protecting data as it moves across untrusted networks.

Data-in-motion encryption ensures confidentiality, and two-factor authentication ensures strict identity verification.

Why other options are incorrect:

B: Data-at-rest encryption is important but not as critical as controlling data in motion for Zero Trust.

C: Categorization helps in segmentation but is not the core Zero Trust principle.

D: High availability is a design requirement, not the primary Zero Trust security control.

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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.

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 and 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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