Free Practice Questions for Cisco 400-007 Exam

In PIM Sparse Mode, when the Last-Hop Router (LHR) receives multicast traffic on the shared tree (*,G), it performs an RPF check based on the RP address, not the multicast source address. In the diagram:

The LHR has IGP cost 10 towards the RP.

The shared tree (*,G) uses RP as the RPF target.

Since multicast traffic on (*,G) arrives on the interface toward RP (correct RPF interface), the RPF check succeeds.

Therefore, the multicast traffic is successfully switched toward the receivers.

This behavior is fully aligned with CCDE v3.1 multicast design principles, which emphasize clear understanding of RPF behavior both on shared trees (*,G) and source trees (S,G).

Why other options are incorrect:

A: The RPF check is not performed against the source in (*,G); it uses RP.

B: RPF checks are always performed, even on (*,G).

D: RPF is unrelated to the receiver address.

FCoE (Fibre Channel over Ethernet) requires a lossless Ethernet transport, typically achieved using Data Center Bridging (DCB) features such as Priority Flow Control (PFC). Only technologies that can preserve Ethernet frames end-to-end and support lossless characteristics can properly carry FCoE:

A. DWDM (Dense Wavelength Division Multiplexing): Operates at the physical layer and is transparent to Ethernet, preserving frame integrity and lossless characteristics across long distances.

B. EoMPLS (Ethernet over MPLS): Carries Ethernet frames directly over MPLS and can be engineered to support low-loss, low-latency transport appropriate for FCoE.

Why other options are incorrect:

C. SONET/SDH encapsulates Ethernet but is not suitable for FCoE due to differences in timing and buffering.

D. Multichassis EtherChannel over pseudowire may introduce additional control plane complexity and loss characteristics.

E. VPLS introduces MAC learning, flooding, and buffering behaviors that can cause frame loss, which is not compatible with FCoE requirements.

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B (Kubernetes):Kubernetes is designed for container orchestration with full state-awareness, handling deployment, scaling, failover, and service discovery. It continuously monitors and maintains the desired state across distributed microservice deployments.

Other options explained:

A: Puppet handles configuration management, not container orchestration.

C: Ansible provides automation but lacks native orchestration state tracking.

D: Terraform handles infrastructure provisioning, not runtime service orchestration.

B (Dynamic real-time change):SDN must adapt dynamically as network demands and application requirements evolve.

E (Integration of device context):Understanding device-level status, capabilities, and resource availability allows controllers to make informed decisions, reducing visibility gaps.

Other options explained:

A: On-demand growth is a business benefit but not related to visibility/performance gaps.

C: Reverting to legacy behaviors undermines SDN benefits.

D: Peer-to-peer controllers help scale, but not directly tied to visibility gaps.

Table Description automatically generated with medium confidence

B (Platform as a Service – PaaS): In a PaaS model, the cloud provider manages the operating system, middleware, runtime, and platform stack. The customer is only responsible for deploying and managing the application itself.

This abstraction allows developers to focus on application logic without worrying about the infrastructure or platform details.

Other options explained:

A (IaaS): Customer manages OS, middleware, and runtime; provider manages hardware and virtualization.

C (SaaS): Customer simply consumes the application; all layers are managed by the provider.

D (BMaaS): Bare Metal as a Service — customer has full control over hardware and all software layers.

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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.

E (Infrastructure ACLs): iACLs control what traffic can reach network infrastructure devices, directly securing the data plane.

G (Routing Protocol Authentication): Prevents malicious or spoofed routing updates which directly protect data plane routing decisions.

Why other options are incorrect:

A: Warning banners are management plane hardening.

B: Redundant AAA is management/control plane hardening.

C: CPPr protects the control plane.

D: SNMPv3 secures management plane.

F: Disabling unused services typically applies to management plane or control plane, not data plane.

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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.

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.