Cisco Updated 400-007 Exam Questions and Answers by hasan

IPv6 multicast supports two key mechanisms for Rendezvous Point (RP) discovery:

A. Embedded RP: The RP address is embedded within the multicast group address (ff70::/12). This allows automatic RP discovery by routers and eliminates the need for signaling protocols.

C. BSR (Bootstrap Router): Used in IPv6 as a replacement for Auto-RP (which is IPv4-specific), BSR dynamically announces the RP to multicast routers in the domain.

Other options:

B. MSDP: Not supported in IPv6 multicast since source registration and discovery are handled differently.

D. Auto-RP: IPv4-specific and not supported in IPv6.

E. MLD: Manages listener (receiver) membership, not RP discovery.

A (Bottom-Up Approach): Starts with the evaluation of current infrastructure (hardware, protocols, configurations), followed by design adjustments based on identified gaps.

C (Top-Down Approach): Starts from business and application requirements, translating them into technical design and network architecture.

Both approaches are widely used in network design methodology depending on business requirements and organizational maturity, directly referenced in CCDE v3.1 design models.

Why other options are incorrect:

B & D: These are not valid or recognized network design approaches.

E: Three-tier is a network architecture model, not a design approach.

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A (VXLAN offers native loop avoidance): VXLAN uses Layer 3 underlay with encapsulation, inherently avoiding Layer 2 loops common in traditional Layer 2 fabrics.

Why other options are incorrect:

B: Storm control mitigates broadcast storms but doesn't prevent loops.

C: vPC+ helps but doesn’t replace VXLAN's loop-free architecture.

D: BPDU Guard helps protect edge ports, but loop prevention in VXLAN is primarily handled by its Layer 3 foundation.

B (Point-to-multipoint network type): OSPF point-to-multipoint allows the hub to see the DMVPN topology correctly without complex neighbor relationships.

E (Set spokes priority to 0): Ensures the hub always becomes DR, maintaining predictable OSPF adjacency behavior.

Other options explained:

A: Broadcast mode is inefficient and unnecessary in DMVPN designs.

C: Mixed network types complicate adjacency maintenance.

D: Manually setting the hub priority is redundant when spokes are at priority 0.

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