How to set base_reachable_time_ms?

Issue

• How to set base_reachable_time_ms?

man page ARP(7):

       base_reachable_time (since Linux 2.2)
              Once a neighbor has been found, the entry is considered to be valid for at least a random value between base_reachable_time/2
              and 3*base_reachable_time/2.  An entry's validity will be extended if it receives positive feedback from higher level  proto‐
              cols.  Defaults to 30 seconds.  This file is now obsolete in favor of base_reachable_time_ms.

       base_reachable_time_ms (since Linux 2.6.12)
              As for base_reachable_time, but measures time in milliseconds.  Defaults to 30000 milliseconds.