CCIE CCIE Network Design 3

Question 1

In a dual-stack IPv4/IPv6 network design, which transition mechanism translates IPv6 packets to IPv4 at the network edge to allow IPv6-only hosts to communicate with IPv4-only destinations?

Accepted Answer

NAT64 with DNS64

Answer

NAT64 translates IPv6 source addresses to IPv4 at the border, while DNS64 synthesizes AAAA records for IPv4-only destinations, enabling seamless communication from IPv6-only clients.

Question 2

A designer is evaluating whether to use IS-IS or OSPF as the underlay IGP for a large SP MPLS core. Which characteristic gives IS-IS an advantage in very large SP networks?

Accepted Answer

IS-IS is not tied to IP and can continue operating during IP address misconfiguration

Answer

IS-IS runs directly over Layer 2 (CLNS) independent of IP, so IP addressing misconfigurations or failures do not prevent IS-IS adjacencies from forming, improving network resilience.

Question 3

Which design consideration is most critical when deploying Cisco SD-WAN (Viptela) to replace a legacy MPLS WAN for a 200-site enterprise?

Accepted Answer

Designing the vSmart controller placement for low-latency OMP route distribution

Answer

The vSmart controller distributes OMP routes and policies to all vEdge devices; poorly placed controllers introduce latency in policy enforcement and route convergence across all 200 sites.

Question 4

A network designer must ensure that a data center can survive the failure of an entire power zone (affecting half the physical servers). Which server connectivity design achieves this?

Accepted Answer

Dual-homed servers with NICs connected to ToR switches in different power zones

Answer

Dual-homed NICs connecting to Top-of-Rack switches in separate power zones ensure that if one zone loses power, the surviving NIC and its ToR maintain connectivity for all servers.

Question 5

When designing a campus network for 802.1X port-based authentication, which component acts as the central policy decision point that evaluates authentication requests from network access devices?

Accepted Answer

Cisco ISE (Identity Services Engine)

Answer

Cisco ISE functions as the RADIUS server and policy decision point, evaluating 802.1X supplicant credentials, posture, and profiling data to return dynamic authorization policies to switches.

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CCIE - Cisco Certified Internetwork Expert Practice Test

CCIE CCIE Network Design 3