What protocol uses smaller stratum numbers to indicate that the server is closer to the authorized time source than larger stratum numbers?

The protocol that uses smaller stratum numbers to represent a closer proximity to the authorized time source is Network Time Protocol (NTP). In NTP, the stratum value is crucial for determining the hierarchy of time sources in the network. Stratum 0 is the reference clock (such as atomic clocks or GPS clocks), stratum 1 servers synchronize directly with these reference clocks, and as you move down the hierarchy, stratum 2 servers synchronize with stratum 1 servers, and so forth.

By utilizing smaller stratum numbers, NTP can effectively convey the reliability and accuracy of time by indicating how directly a server is connected to the primary time source. This hierarchical structure ensures that time synchronization is efficient and reliable across large networks. The protocol effectively balances the load of time requests and helps maintain consistency in time across devices, which is vital for various applications that require precise timekeeping.

Other protocols listed, such as DHCP (Dynamic Host Configuration Protocol) and RADIUS (Remote Authentication Dial-In User Service), serve entirely different purposes in network management and security. TFTP (Trivial File Transfer Protocol) is used for file transfers but does not deal with time synchronization. Hence, these protocols do not utilize a stratum concept or hierarchical time management,