Define protocol signoff criteria for the product, configuration and selected specification revision. Typical evidence includes reviewed requirement traceability, passing required checks, coverage closure/exclusions, regression results, open-issue disposition and explicit residual risks; do not claim a universal checklist is sufficient.
Separate protocol signoff from functional signoff.
Emulation adds real traffic but slower debug — use for final confidence.
Post-silicon: compare observable behaviour with the specification and pre-silicon models while accounting for different visibility and traffic control.