Cisco Updated 400-007 Exam Questions and Answers by darius

To support high-bandwidth, low-latency Layer 2 communication between DB Server 1 and DB Server 2, you must create a direct Layer 2 path between SW1 and SW2. Using REP (Resilient Ethernet Protocol) segments ensures loop-free Layer 2 operation without the drawbacks of STP convergence delays.

Option C is correct: Adding a third REP segment (Segment 3) directly between SW1 and SW2 isolates the traffic between the two DB servers and ensures deterministic behavior with fast convergence.

Option A (LACP with STP) introduces STP blocking and doesn’t align well with REP's control plane.

Option B and D: Overloading existing segments or splitting new links into existing REP segments does not offer the same direct path, bandwidth, or deterministic behavior.

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In MPLS networks, the MPLS header contains a 3-bit EXP (experimental) field that is used for QoS classification. Since the customer edge (CE) is managed by the service provider, it is common and best practice to map customer traffic classification (DSCP) into MPLS EXP at ingress into the MPLS core. This allows consistent QoS treatment throughout the core.

DSCP provides granular QoS markings (6-bit field, 64 values) which can be easily mapped to 3-bit EXP (8 values).

Mapping DSCP to EXP supports the 6-class model required by many service providers.

Why other options are incorrect:

A, C: IP CoS and IP precedence are legacy and not as granular as DSCP.

B: Flow-label is used in IPv6 for traffic engineering, not for MPLS QoS classification.

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Cloud Bursting is the process by which applications or workloads that run in a private cloud or data center environment are "bursted" into a public cloud infrastructure during high-demand periods. This prevents service degradation and ensures performance continuity without manual intervention.

In CCDE design strategy terms, this enables:

Elastic scalability

Cost-effective use of public infrastructure on-demand

Seamless service delivery to end users

Options like “cloud policing” and “cloud shaping” are not standard terms, and “cloud spill” is not an established mechanism. “Cloud bursting” is the correct architectural mechanism that addresses this overflow requirement.

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iBGP’s full mesh requirement refers to logical BGP session establishment, not physical network design. As long as reachability exists between iBGP peers (through an IGP like OSPF or IS-IS), iBGP sessions can be established regardless of physical topology (ring, star, partial mesh, etc.).

Key CCDE v3.1 design principles:

Logical iBGP mesh ≠ physical mesh requirement.

Physical topologies can be optimized independently of iBGP peering structure.

Control plane designs like route reflectors or confederations further optimize scalability without changing physical topology.

Why other options are incorrect:

B: iBGP works on any topology where IP reachability exists.

C: Physical full mesh is unnecessary for iBGP.

D: iBGP functions over any IGP-provided reachability domain, including rings.