400-007 Practice Questions

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.

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The question describes a network that requires virtualization at both control and data plane levels using VLANs and VRFs. This architecture aligns with:

Path isolation (A): Achieved using VRFs and VLANs, ensuring traffic separation at Layer 2 and Layer 3 across the entire network.

Group virtualization (C): Refers to grouping users or resources (such as departments or tenants) into isolated segments that remain logically separated throughout the campus fabric.

Other options explained:

B (Session isolation): More aligned with application or session-layer security, not data/control plane virtualization.

D (Services virtualization): Typically related to virtualizing network services (firewalls, load balancers).

E (Edge isolation): Not a standard design term in CCD

E.  

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B (Use only secure protocols): Management and administrative access to Internet edge routers must use secure protocols (SSH, SNMPv3, HTTPS) to prevent interception or unauthorized access.

E (Restrict administrative access): Limiting administrative access via interface ACLs and clear login banners ensures that only authorized personnel can access the system, satisfying compliance and security requirements.

Other options explained:

A: Filtering infrastructure IP space is good hygiene but not directly related to compliance.

C: Logging is valuable for operations and incident response but not a compliance control by itself.

D: EBGP advertisements relate to routing policy, not compliance regulation.

B (Segment Routing): Allows traffic engineering and micro-segmentation across networks by steering traffic based on policies and labels.

D (Firewalls): Provide Layer 4-7 segmentation and security enforcement between segments.

Why other options are incorrect:

A: Policy-based routing influences forwarding, but is not a segmentation technology.

C: Data plane markings support QoS but do not create segmentation boundaries.

E: Filter lists are used in routing policy, not for full network segmentation.

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