Cisco Certified Design Expert (CCDE) Advanced Practice Exam: Hard Questions 2025

A global enterprise is redesigning its WAN to support critical real-time collaboration and bulk data replication. The business requires that real-time traffic be protected during failures, but the WAN cost must be controlled. The current proposal suggests using multiple diverse carriers with SD-WAN, active/active transport usage, and application-aware routing. Which additional design choice best balances resiliency with predictable performance during brownouts and partial failures (not complete link-down)?

A service provider is designing a dual-region data center interconnect (DCI) with EVPN for multi-tenant L2/L3 services. Requirements: (1) tenant subnets must be stretched between regions for a subset of workloads, (2) minimize failure domain and blast radius, (3) support active/active use of both regions, and (4) avoid spanning-tree dependence across the DCI. Which design approach best meets these requirements with the least operational risk?

A campus core is being redesigned with a collapsed core/distribution and multiple access blocks. The access layer uses L2 to distribution with first-hop redundancy and Rapid PVST. Operations reports intermittent micro-loops and multicast flooding during uplink failures, and the business wants faster convergence while reducing L2 complexity. Which redesign is most appropriate while maintaining scalable segmentation and minimizing the scope of change at the edge?

An enterprise operates two data centers and multiple branches. The design uses eBGP between branches and two ISP edges, and iBGP within each site. During an ISP partial outage, traffic to some SaaS destinations oscillates between ISPs, causing session resets. The routing team confirms both ISPs continue to advertise prefixes, but path quality varies and BGP attributes remain stable. Which design change most directly addresses the oscillation while keeping BGP policy manageable?

A large enterprise is migrating from a legacy IGP-only backbone to an MPLS-enabled core with L3VPN for segmentation. The enterprise requires: (1) strict isolation between business units, (2) ability to share select services (DNS, logging) centrally, and (3) minimal route leakage risk. Which design best meets the requirements with strong control and operational clarity?

A multi-site enterprise runs IPv6-only in several campus segments but must reach IPv4-only SaaS services. The design must avoid deploying dual-stack to endpoints, minimize operational complexity, and provide predictable failure behavior. Which architecture is the best fit?

A financial institution needs end-to-end QoS across a mixed underlay (MPLS, Internet VPN, and DCI) for voice, trading apps, and backups. The institution experiences intermittent voice degradation during backup windows even though WAN links are not fully saturated. Which design action is most likely to resolve the issue while preserving fairness and preventing starvation?

A multinational company must provide secure remote access for employees and third parties. Requirements: (1) device posture and user identity-based access, (2) least-privilege segmentation to internal apps, (3) minimize lateral movement if credentials are compromised, and (4) reduce operational complexity across multiple VPN concentrators. Which security design best meets these requirements?

A company is designing Internet edge security for multiple business units sharing a common set of firewalls. Requirements: (1) prevent one tenant’s policy changes from impacting others, (2) provide deterministic outbound NAT and logging per tenant, (3) enable selective shared services (e.g., URL filtering) without full policy coupling, and (4) support future insertion of additional security services. Which architecture best fits?

A network team is implementing automation for a multi-vendor enterprise WAN and data center. The primary failures in prior automation attempts were: (1) configuration drift between intended and actual state, (2) inconsistent rollbacks during partial failures, and (3) poor visibility into whether changes met design intent (e.g., policy compliance). Which approach best addresses these issues while keeping change risk low?