[jve]

Is that a standard?

              Network Time Protocol Best Current Practices
                         draft-ietf-ntp-bcp-02

1. Introduction

   NTP Version 4 (NTPv4) has been widely used since its publication as
   RFC 5905 [RFC5905].  This documentation is a collection of Best
   Practices from across the NTP community.

[heisenbit]

Don't think it is a standard, looks like work in progress.

Imho a bit short notice to publish something like that Nov. 30th. Just at the time when they had to start advertising the leap second in NTP (or not advertise it where smearing). Not sure but somehow it sounds in draft-ietf-ntp-bcp-02 that that clients may need attention.

   Clients that are connected to leap smearing servers must not apply
   the "standard" NTP leap second handling.  So if they are using ntpd,
   these clients must not have a leap second file loaded, and the
   smearing servers must not advertise that a leap second is pending.