Editing Leap second (section)

===Implementation differences===
Not all clocks implement leap seconds in the same manner. Leap seconds in [[Unix time]] are commonly implemented by repeating 23:59:59 or adding the time-stamp 23:59:60. [[Network Time Protocol]] (NTP) freezes time during the leap second,<ref>{{Cite web |date=10 February 2010 |title=NIST Internet Time Service (ITS) |url=https://www.nist.gov/pml/time-and-frequency-division/time-distribution/internet-time-service-its |website=NIST}}</ref> some time servers declare "alarm condition".{{citation needed|date=October 2019}} Other schemes ''smear'' time in the vicinity of a leap second, spreading out the second of change over a longer period. This aims to avoid any negative effects of a substantial (by modern standards) step in time.<ref>{{citation|rfc=7164|author=Kevin Gross|title=RTP and Leap Seconds|date=March 2014}}</ref><ref name=google-smear /> This approach has led to differences between systems, as leap smear is not standardized and several different schemes are used in practice.<ref>{{cite web | website = Bureau International des Poids et Mesures | url = https://www.bipm.org/documents/20126/77823803/INTRODUCTION-DRAFT-RESOLUTION-D.pdf/62f31b32-bfe4-969f-5d29-1dc08cc907bb?version=1.2&t=1669373890355&download=true | title = Draft Resolution D: 'On the use and future development of UTC' | last1 = Dimarcq | first1 = Noël | last2 = Tavella | first2 = Patrizia  | date = 17 November 2022 | page = 7}}</ref>