RFC 5218 Quiz

**Explanation:** A: publication is not deployment success. B: RFC 5218 evaluates both achievement of original goals and wide deployment; “wide” can be intra-domain. C: implementation evidence matters, but one lab test does not establish broad use.

**Explanation:** A: scale limits are a different question. B: specification access does not determine this cost-benefit result. C: a protocol needs benefits that outweigh deployment and operational costs, preferably with costs and benefits aligned for adopters.

**Explanation:** A: early adopters obtain value without universal support, and backward compatibility lowers coordination cost. B: a flag day is the worst-case deployment dependency. C: misaligned costs and benefits remove the incentive to adopt.

**Explanation:** A: Open code lowers the cost of trying, testing, and improving an implementation. B: Worldwide unrestricted specification access permits independent implementation. C: Mandatory single-vendor licensing increases adoption cost and creates a control dependency. D: Stability and permanence let implementers keep interoperating after the original creator leaves.

**Explanation:** A: technically inferior proposals can win when they provide value, deploy easily, or are more open. B: RFC 5218 ranks real need and incremental deployment as key initial factors while retaining simplicity, clarity, and robustness as important design qualities. C: the RFC does not dismiss technical quality; it distinguishes stages of success.

**Explanation:** A: extension machinery is not free, especially for a specialized protocol. B: extensibility can enable wild success and later fixes. C: general-purpose protocols benefit most clearly, while specialized protocols should add extensibility deliberately rather than reflexively.

**Explanation:** A: a broadcast-storm “knee” near the design target prevents growth beyond the initial space. B: diagnostics do not remove the underlying scaling limit. C: implementation language is unrelated and would reduce freedom of implementation.

**Explanation:** A: design decisions appropriate to the original purpose may be wrong elsewhere. B: RFC 5218 calls out performance problems, invariant-breaking modifications, and increased attacker value—potentially “death by success.” C: wild success can be a reason to revise and harden a protocol.

**Explanation:** A: popular protocols become more attractive targets. B: inability to evolve makes known flaws harder to correct. C: RFC 5218 distinguishes initial adoption from survival under attack and warns that weak security combined with limited extensibility is especially dangerous.

**Explanation:** A: it aligns value with adopters, supports incremental deployment, and reduces coordination while keeping compatibility explicit. B: a flag day is a major adoption barrier. C: secrecy prevents independent evaluation and implementation. RFC 5218 does not guarantee success, but it identifies these as materially different conditions.