Which two design solutions ensure sub 50 msec of the convergence time after a link failure in the network? (Choose two)

BFD detects link failures in milliseconds but does not itself reroute traffic - it signals the routing protocol to reconverge, and that reconvergence process typically exceeds 50ms.

Ti-LFA (Topology Independent Loop-Free Alternates) uses segment routing to pre-compute backup paths guaranteed to be loop-free regardless of topology, providing 100% failure coverage and allowing immediate traffic switchover in under 50ms when any single link or node failure is detected.

Minimal BGP scan time reduces the interval between BGP table scans to speed prefix withdrawal processing, but end-to-end BGP convergence cannot reliably achieve sub-50ms restoration.

MPLS-FRR (Fast Reroute) pre-establishes bypass or detour LSPs before any failure occurs, so when a protected link or node fails the local repair point switches traffic to the backup tunnel in under 50ms without waiting for end-to-end routing reconvergence.

IGP fast hello timers reduce failure detection time, but the subsequent SPF calculation and route propagation required for IGP reconvergence typically takes longer than 50ms.