300-420 Exam Dumps : Designing Cisco Enterprise Networks (ENSLD) v1.1

The best answer is to use a single IP address for a static NAT entry that represents the server with a nonoverlapping address. When two companies use overlapping private address space, routing directly between the networks can fail because each side may already have a local route for the same prefix. The requirement is narrow: users in the acquired company need access to one server in Company A, and the design must conserve address space. A static NAT mapping for the server solves the destination overlap problem with one translated address, giving remote users a unique reachable address for that server without renumbering either company. Overload NAT is normally used to translate many inside clients behind one address for outbound access; it is not the most precise solution for publishing one overlapping server. One-to-one NAT for every user wastes addresses and adds operational overhead. Readdressing the acquired company would solve the overlap permanently, but it does not conserve effort or address space. Therefore, a single static NAT entry for the server is the most efficient design.

BFD is not required for the specific failure described: a physical fiber break on point-to-point routed links. In a Layer 3 campus or routed-access design, a direct physical link failure is detected by the interface state change, so the routing protocol can react immediately without waiting for hello/dead timers. Cisco campus design guidance favors point-to-point routed links partly because they give rapid convergence and avoid STP delays. BFD is valuable when a forwarding-path failure is not reliably detected by Layer 1 or Layer 2, or when a protocol adjacency must detect loss faster than its native timers. It does not automatically create convergence by itself; it detects failure and notifies the routing protocol. For a clean fiber cut on a routed point-to-point link, link-down detection is already fast enough for sub-second failover in the design. OSPF timer tuning is also not the preferred design answer for this physical-failure case. Reference topics: routed access design, point-to-point links, link-failure detection, BFD, OSPF convergence.

An end-to-end QoS strategy with an SLA is the best fit for an application that cannot tolerate drops and requires very low latency across countries. The customer is asking for guaranteed service behavior, not just local classification on one router. A service line with an SLA defines the expected treatment across the provider network, including bandwidth, delay, jitter, and loss commitments. This is especially important for industrial or manufacturing applications that process large data chunks and are sensitive to packet loss. A purely domain-based PHB design can mark and forward traffic differently at each hop, but it does not by itself guarantee the business outcome unless backed by an end-to-end service agreement. A flow-based approach with per-flow queuing on every ISP node would consume more provider resources and scale poorly. FEC can help selected traffic but does not replace a QoS service model. Reference topics: QoS design, service-level agreements, end-to-end QoS, low-latency applications, loss-sensitive traffic, provider WAN services.