Free Practice Questions for Cisco 400-007 Exam

D (SAML2.0):SAML2.0 is widely used for federated identity management in enterprise environments, supporting Single Sign-On (SSO) across multiple applications and domains.

Other options explained:

A: OAuth2 is primarily for authorization, not identity federation.

B: OpenID Connect extends OAuth2 for authentication but is more common for consumer web apps than enterprise SSO.

C: OpenID is older and largely replaced by OpenID Connect.

A (Enhance TCP performance):Path MTU Discovery allows TCP to dynamically learn the maximum transmission unit (MTU) along the path and avoid fragmentation. This reduces retransmissions, maximizes throughput, and improves efficiency for TCP-based applications such as BGP.

Other options explained:

B/C: PMTUD does not affect convergence times.

D: Loop prevention is unrelated to MTU discovery.

B (RPVST+ — Rapid Per VLAN Spanning Tree Plus): Provides fast convergence while blocking redundant paths to prevent loops — fail closed behavior under failure scenarios.

C (MST — Multiple Spanning Tree): Provides loop prevention and isolates failures to specific instances (VLANs), maintaining fail closed protection.

Why other options are incorrect:

A: EIGRP is a routing protocol; does not operate at Layer 2 to provide fail-closed loop protection.

D: L2MP (Layer 2 Multipathing) allows multiple active links but requires additional loop prevention mechanisms.

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OSPF uses pacing timers to control how quickly it sends LSAs to neighbors to prevent network flooding and CPU spikes:

C. Retransmission-pacing timer: Controls spacing between retransmitted LSAs queued after a lost or unacknowledged transmission.

E. Flood-pacing timer: Controls spacing between consecutive LSAs when flooding new information to peers.

These timers are critical in scaling OSPF in dense or unstable topologies and are key to tuning control plane convergence performance without destabilizing routers.

In modern network architectures, particularly those using NFV (Network Function Virtualization),Service Chainingis used to direct traffic through a sequence of virtualized network functions (VNFs)—such as firewalls, load balancers, NAT devices, etc.—based on service requirements.

Service chaining allows:

Dynamic or policy-based redirection of traffic through VNFs

Simplified orchestration of network services

Scalability and flexibility across multi-tenant or virtualized environments

CCDE v3.1 emphasizes service chaining as a key enabler in cloud-native and virtualized architectures, ensuring services are efficiently composed based on application or security needs.

Why other options are incorrect:

A and E (Bridging/Switching): Refer to traditional Layer 2 forwarding and do not provide VNF sequencing logic.

C and D: “Linking” and “Daisy chaining” are not standard or scalable methods in NFV environments.

The hub CE router is receiving IP SLA probes from all spokes, processing and responding to every request. As more spokes are added, the CPU workload on the hub increases exponentially due to:

Processing incoming IP SLA packets.

Generating and transmitting responses.

Monitoring CPU utilization at the hub ensures early detection of processing bottlenecks that could impact SLA accuracy and overall performance — a core CCDE v3.1 business-driven design consideration in centralized measurement architectures.

Why other options are incorrect:

A & B: Spoke resources are minimally taxed.

D: Buffer usage isn't the main limiting factor for IP SLA responsiveness.

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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D: Traditional three-tier architectures (access, distribution, and core layers) require that east-west traffic (between servers or pods in different access layers) traverse up to the distribution or core and then back down—introducing unnecessary hops and latency. This is a key design limitation addressed by spine-leaf and fabric architectures.

Other options:

A: Bandwidth may be sufficient but not optimally utilized due to suboptimal pathing.

B: Security is not inherently compromised by architecture, although microsegmentation is harder.

C: Three-tier architectures can scale, but less efficiently and not without trade-offs like latency and complexity.

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In service provider Ethernet transport environments such as VPLS, Ethernet OAM (Operations, Administration, and Maintenance) is used to provide fault detection, monitoring, and troubleshooting capabilities. The two relevant components here are:

A (Unicast heartbeat messages between MEPs): Maintenance End Points (MEPs) are configured at the edges of the OAM domain (SP-SW1 and SP-SW2). Heartbeat messages can be used to proactively monitor and detect loss of continuity between the endpoints.

B (Enable Connectivity Fault Management): CFM (IEEE 802.1ag) provides end-to-end fault detection, continuity check messages (CCMs), loopback, and link trace mechanisms that operate between MEPs at Layer 2. CFM enables proactive detection of failures and service-level assurance across the provider’s Ethernet segment.

Other options explained:

C: Upward MEPs are not applicable here since these are typically used for customer-facing or hierarchical maintenance domains.

D: E-LMI (Ethernet Local Management Interface) operates between CE and PE for service activation—not applicable for SP-SW to SP-SW fault detection across VPLS.

E: LLDP (Link Layer Discovery Protocol) is for neighbor discovery on directly connected interfaces—not suitable for end-to-end fault detection across a VPLS domain.

This design solution aligns fully with CCDE v3.1 principles for service provider Layer 2 VPN design and Ethernet OAM integration.