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

C (More consistent device configuration):Centralized control allows uniform policy application, eliminating configuration drift across devices.

E (Configure features at network-level rather than device-level):Controller-based networks abstract network services from individual devices, enabling network-wide configuration from a single source of truth.

Other options explained:

A: Forwarding tables still exist in both architectures.

B: Traditional networks offer per-device flexibility; controllers abstract this.

D: APIs are usually provided at controller level, not per device.

C: GLOP addressing is defined in RFC 2770, assigning a portion of the 233.0.0.0/8 range for each AS based on their 16-bit ASN. This allows each AS to use a /24 of globally unique multicast addresses without coordination from IANA.

Other options:

A: 239.0.0.0/8 is the administratively scoped multicast address space.

B: 224.0.0.0/24 is reserved for local link-scoped protocols (e.g., OSPF, RIP).

D: 232.0.0.0/8 is the Source-Specific Multicast (SSM) range.

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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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In IoT environments, especially in manufacturing plants, security is the primary concern during migration:

IoT devices often have limited security capabilities and may introduce vulnerabilities if not properly segmented, authenticated, and monitored.

Manufacturing plants operate critical systems where availability, safety, and integrity are paramount.

CCDE v3.1 emphasizes securing data, devices, and control systems as a top priority during IoT migrations.

Other options explained:

A: Sensors are part of the IoT solution but not the primary migration concern.

C: Applications are important but typically come after securing connectivity and endpoints.

D/E: Infrastructure elements are secondary to security in the migration assessment.

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In this architecture:

A secure web proxy is introduced to inspect and filter all web (HTTP/HTTPS) traffic.

Remaining traffic (non-web) must pass through an NGFW with IPS capabilities.

Both the web proxy and NGFW reside between the collapsed distribution/core and internet edge.

To enforce that all web traffic is directed to the proxy appliance for inspection and non-web traffic follows its usual path to the NGFW:

A. Policy-Based Routing (PBR) on the Collapsed Core

This allows traffic classification based on destination port (e.g., TCP 80/443) and selectively reroutes web traffic to the proxy. Non-web traffic continues toward the NGFW. PBR is essential here because traditional routing (based only on destination IP) would not differentiate between traffic types.

D. Static Routing on the Appliance

The proxy appliance must return the traffic back toward the NGFW for final processing and internet egress. This is typically achieved using static routes on the proxy device, ensuring the return path sends packets back to the correct firewall interface for consistent inspection.

❌ B. Policy-based routing on the internet edge: Not applicable here, as rerouting must occur closer to the source (collapsed core), before traffic reaches the internet edge.

❌ C. Policy-based routing on firewalls: This adds unnecessary complexity. Firewalls should focus on enforcing security policies, not traffic redirection logic in this scenario.

This approach adheres to CCDE v3.1 best practices by separating policy enforcement functions and enabling scalable, deterministic traffic flow through layered security appliances.

To achieve subsecond convergence in IS-IS or OSPF networks and quickly detect both:

Link-layer failures (e.g., interface flaps)

Control-plane adjacency loss

The best solution is:

C. BFD (Bidirectional Forwarding Detection): A lightweight protocol that enables subsecond failure detection, independent of the IGP timers, by establishing fast detection sessions over forwarding paths.

This is widely deployed in high-performance networks to accelerate convergence without compromising routing stability.

Why other options fall short:

A. Debounce timers delay interface-down events (not suitable when fast detection is required).

B. Fast hellos affect hello interval but are still slower and CPU-intensive.

D. LSP fast flood improves LSP propagation but doesn’t address failure detection speed.

This solution is central to CCDE “Protocol Design Implications” where rapid failure detection and recovery drive the convergence architecture.

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Control plane hardening is a critical aspect of securing infrastructure devices. Recommended measures include:

A. Routing protocol authentication: Prevents unauthorized devices from injecting false routes by requiring secure key-based authentication (e.g., MD5 or SHA for OSPF/BGP).

B. SNMPv3: Provides secure management through authentication and encryption, preventing interception or modification of SNMP traffic.

C. Control Plane Policing (CoPP): Enforces rate limits and filtering for traffic directed to the device ' s CPU, protecting against DoS and control plane overloads.

Why other options are incorrect:

D. Redundant AAA servers support authentication resilience but are more about access control than direct control plane protection.

E. Warning banners are a legal and administrative best practice, not a technical control plane defense.

F. Enabling unused services is the opposite of best practices and increases the attack surface.

These control-plane protections are emphasized in CCDE v3.1 design guidance for resilient and secure infrastructure designs.