Cisco 400-007 - Cisco Certified Design Expert (CCDE v3.1)

MLD (Multicast Listener Discovery) snooping for IPv6 operates similarly to IGMP snooping in IPv4. It tracks listener reports to restrict multicast flooding within a Layer 2 domain.

C: Querier elections are triggered when a querier becomes unreachable or its IP address changes.

D: The querier with the lowest IPv6 address is elected as the active querier, which manages report/query communication.

Other options:

A: QoS is not automatically enabled with MLD snooping.

B: MLD querier functionality operates per VLAN—not per group—so only one querier is elected per VLAN.

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B (Confidentiality):Protects data from unauthorized access or disclosure.

E (Integrity):Ensures data remains accurate and unaltered.

F (Availability):Ensures that data and systems are accessible when needed.

Other options explained:

A: Cryptography is a tool used to achieve confidentiality, integrity, or authentication, but it ' s not part of the CIA triad itself.

C/D: Authorization and identification are security processes, but not part of the core CIA triad.

A (Additional MPLS provider):True path diversity includes provider diversity to eliminate the possibility of shared failures within a single provider’s infrastructure. Multiple providers minimize correlated failures, increasing WAN availability.

Other options explained:

B: Out-of-band management improves operational access but doesn ' t address WAN availability.

C: Dual-homing branches is valuable but not directly related to the data center’s WAN failure condition.

D: Hardware redundancy improves local device availability but doesn ' t mitigate WAN failures.

B (OpenConfig):OpenConfig YANG models are vendor-neutral, community-driven standards designed to simplify multi-vendor network automation and interoperability — ideal for heterogeneous SDN fabrics.

Other options explained:

A: Proprietary models limit flexibility and interoperability.

C: Native models are vendor-specific.

D: IETF YANG models exist but are not as comprehensive for full operational SDN automation as OpenConfig.

Comprehensive and Detailed Explanation From Exact Extract of Design Expert (CCDE)

Controller-based networks centralize control logic, abstracting hardware complexity and providing consistency. This results in:

C. Abstraction: Devices are treated as policy endpoints rather than configuration silos, simplifying network operations and scalability.

E. Consistent Configuration: Policies and configurations are pushed uniformly across all devices from the controller, reducing human error and improving compliance.

These features align with CCDE v3.1 recommendations for modern, policy-driven, and scalable architectures that are easier to manage and automate.

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Graphical user interface Description automatically generated with medium confidence

UplinkFast is an STP optimization feature designed primarily for access layer switches to reduce convergence time when a direct link failure occurs. When a primary uplink fails, UplinkFast immediately activates a backup uplink port without waiting for traditional STP convergence.

It is most effective on access layer switches where redundant uplinks to distribution switches exist.

On distribution switches, it may also be useful if they have multiple uplinks toward the core.

UplinkFast is not recommended for core switches as these typically don’t have redundant uplinks toward lower-tier devices.

It is not designed to resolve interoperability issues between different STP versions or to adjust hello timers.

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