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

Dense Wavelength Division Multiplexing (DWDM) enables multiple optical signals to be transmitted simultaneously on different wavelengths over a single fiber, allowing:

B: Efficient bandwidth expansion without laying new fiber infrastructure.

C: Topology flexibility and service protection using built-in features like optical protection switching, automatic fault detection, and self-healing rings.

Why other options are incorrect:

A: Oversubscription of bandwidth applies more to packet-based networks, not DWDM optical layer.

D: Chromatic dispersion is managed but not an inherent “intelligent” feature in DWDM.

E: Service protection at the DWDM layer operates independently of upper layer protocols.

—

B (Northbound APIs):Northbound APIs allow applications to communicate with the SDN controller to express service requests and provide policy intent. The controller translates these into instructions for the underlying infrastructure.

Other options explained:

A: Southbound APIs connect controllers to forwarding devices.

C: Orchestration coordinates workflows across domains but doesn’t directly connect applications to controllers.

D: The SDN controller receives the northbound API calls but is not the API itself.

The primary goal of resilient modular network design is to minimize the operational impact of failures by automating recovery and isolating fault domains.

C: Reducing failures that require manual intervention improves availability, reduces downtime, and ensures stability even under fault conditions.

Why other options are incorrect:

A: This is a limitation to avoid, not a design driver.

B: Minimizing app downtime is an outcome, not the operational driver itself.

D: Development time is not related to operational network resiliency.

—

In addition to business requirements, network architects must also account for non-business constraints such as legal, regulatory, and industry compliance. These may include standards like GDPR, HIPAA, PCI-DSS, or country-specific data sovereignty and retention laws.

Compliance is not typically driven by direct business value but by external mandates that influence how the network must be designed, implemented, and operated. Ignoring compliance requirements can result in significant legal or financial penalties and is therefore a core component of any responsible network design.

Other options such as:

A. Location — may impact design (e.g., latency, availability), but it is often categorized as a technical or logistical consideration.

B. Cost — is a business constraint.

C. Time — is considered a project or delivery constraint, also typically business-driven.

Strictly Centralized Control Plane: Single point of failure and difficult to horizontally scale, most often used in experimental SDN controllers.

Semi or Logically Centralized Control Plane: Possible convergence difficulties, N instances to configure and manage, easy to horizontally scale, just deploy.

Fully Distributed Control Plane: Resilient to many failure points but still susceptible to issues around synchronization of state, canonical approach, one instance of control plane per device (logical or real).