Free Cisco 400-007 Practice Exam with Questions & Answers | Set: 7

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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The distribution layer serves as the boundary between the access and core layers in the three-tier hierarchical design. It plays a crucial role in providing policy enforcement, control, and boundary functions, including:

QoS classification and marking (C): The distribution layer serves as the boundary for Quality of Service policies. It marks and classifies traffic as it moves from access to core layers, ensuring proper QoS treatment in the core.

Redundancy and load balancing (E): The distribution layer provides link redundancy (e.g., dual-homing access layer switches) and performs load balancing to optimize path selection toward the core.

Other options explained:

A (Fast transport): Typically associated with the core layer, which focuses on high-speed forwarding.

B (Reliability): While reliability is a network-wide goal, it’s not a primary function of the distribution layer specifically.

D (Fault isolation): While partial fault containment occurs, primary fault isolation happens at the access layer.

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A (Policy-based routing):Allows classification of traffic based on source, destination, or protocol and applies forwarding policies accordingly, such as sending VoIP over MPLS and best-effort traffic over either link. PBR operates in fast-path switching modes to avoid process switching if properly configured.

Other options explained:

B: Virtual links relate to OSPF, not traffic steering.

C: Visualization is not a network forwarding technology.

D: Floating static routes select one link for all traffic, not per-traffic-type control.

PBR overrides the normal routing table behavior, potentially leading to microloops during reconvergence because forwarding decisions are based on policies rather than updated routing tables.

During fast topology changes, PBR decisions may not adapt as quickly as dynamic routing protocols, causing brief routing inconsistencies.

Why other options are incorrect:

A: PBR can add complexity but does not inherently limit scalability.

C/D: PBR does not directly affect convergence speed but can introduce inconsistency.

B (EAP - Extensible Authentication Protocol):EAP is commonly used for 802.1X port-based authentication, allowing identity-based control for users on the network. This enables policy enforcement, identity-based segmentation (micro/macro segmentation), and leverages existing domain credentials via backend integration.

Other options explained:

A: LDAP is backend directory, not an authentication protocol for access ports.

C: TACACS+ is used primarily for administrative access.

D: RADIUS transports the EAP exchange but is not the authentication protocol itself.

B (MPLS over BGP over mGRE):This design allows enterprises to run MPLS VPNs across their own infrastructure (Overlay VPN) while using MP-BGP for control plane distribution of VPNv4 routes. The mGRE tunnel structure allows scalability as branches grow, while MPLS VPN labels ensure traffic separation.

Other options explained:

A: EIGRP OTT is not scalable for large VPN deployments.

C: DMVPN per VRF becomes complex with high scale growth.

D: Point-to-point GRE per VRF lacks scalability for 60+ sites.

B: In transparent mode, the firewall operates at Layer 2 and can participate in STP to avoid loops.

C: Multicast traffic can traverse the firewall if allowed through transparent bridging rules.

Why other options are incorrect:

A: Transparent mode requires no change to IP addressing.

D: Transparent firewalls do not form routing adjacencies.

E: Routed mode firewalls operate at Layer 3; transparent mode does not insert router hops.

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FCAPS stands for Fault, Configuration, Accounting, Performance, and Security.

D (Authentication) is not a management category within the FCAPS framework.

Authentication is part of security functions but not a standalone FCAPS category.

Why other options are correct FCAPS components:

A: Configuration management

B: Security management

C: Performance management

E: Fault management

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End-to-end network visibility is often hindered by:

Siloed monitoring and logging systems

Vendor-specific platforms that don’t integrate

Inconsistent telemetry across domains (e.g., WAN, DC, Cloud)

Too many disparate solutions lead to data fragmentation, blind spots, and lack of unified analytics. This makes correlating threats and verifying policy enforcement complex. Overlapping controls (A) and manual processes (C) are operational concerns but don’t directly obstruct architectural visibility.

The CCDE blueprint emphasizes cross-domain visibility, consistent policy enforcement, and integration as central to a secure and scalable network design.

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