The leap second is coming Kyusyu Telecommunication Network

The leap second is coming. Kyusyu Telecommunication Network Co. , Inc. (QTNet) Tomonori TAKADA

Agenda • A leap second will be inserted in this year. • How to adjust NTP for the leap second • The insertion of the previous leap second (2012) • QTNet NTP servers overview. • QTNet Plan for The leap second of 2012 • QTNet Plan for The leap second of 2015 Kyushu Telecommunication Network Co. , Inc. 　 1

A leap second will be inserted this year June 30, 2015 (UTC) July 1, 2015 +0900 (JST) 23: 59: 58 23: 59: 60 00: 00 08: 59: 58 08: 59: 60 09: 00 00: 01 09: 00: 01 Kyushu Telecommunication Network Co. , Inc. 　 2

How to adjust NTP for the leap second • Leap Indicator(LI) is used to adjust for the leap second. • The node which is received as “LI=01”, adjusts the host clock by itself using OS/Kernel functionality when inserting the leap second. • LI just indicates that leap second will be happen. a description of the NTP/SNTP Version 4 message format Value and meaning of the Leap Indicator ※ adapted from http: //www. rfc-base. org/txt/rfc-2030. txt Kyushu Telecommunication Network Co. , Inc. 　 3

The insertion of the previous leap second (2012) • The previous leap second was inserted on July 1, 2012 at +0900(JST). • Several problems were reported, especially on Linux. 1. OS rebooted after it received the leap indicator. 2. CPU usage reached 100% on multiple hosts running some specific applications after the leap second was inserted. Kyushu Telecommunication Network Co. , Inc. 　 4

QTNet NTP Servers overview ※NICT is an organization that determines and maintains Japan Standard Time or JST, and distributes JST in various ways. via PSTN Stratum 1 JJY (Dial-up) GPS time server internet ntp server 1 Stratum 2 ntp server 2 peer ntp server 3 peer QTNet Servers Kyushu Telecommunication Network Co. , Inc. 　 5

QTNet Plan for the leap second of 2012 • We did not use the Leap Indicator. • We had gotten information of old OS/Kernel bugs which were relevant to the leap indicator. • Our Stratum 1 servers could adjust for a leap second without using the leap indicator, “Gradually adjust mode”. 　　　　　　 About two hours before the leap second, Our Stratum 1 servers began to set the clock back slowly. Kyushu Telecommunication Network Co. , Inc. 　 6

QTNet Plan for the leap second of 2012 excluded from synchronizing via PSTN Stratum 1 JJY (Dial-up) GPS time server Gradually adjust mode ntp server 2 ntp server 1 Stratum 2 peer Leap indicator distribution ntp server 3 peer QTNet Servers Kyushu Telecommunication Network Co. , Inc. 　 7

Status at the leap second insertion on 2012 via PSTN Stratum 1 JJY (Dial-up) GPS time server Gradually adjust mode ○ ○ Gradually adjust mode ○ ntp server 2 ntp server 1 Stratum 2 peer × ntp server 3 peer × QTNet Servers Kyushu Telecommunication Network Co. , Inc. 　 8

The reasons for the peer status failure 125 minutes before 120 minutes before Start time for setting the clock back via PSTN Stratum 1 1/64 sec ntp server 1 JJY (Dial-up) GPS time server 1/128 sec Polling interval ntp server 3 1/128 sec ntp server 2 Stratum 2 Kyushu Telecommunication Network Co. , Inc. 　 9

Possible plans for The leap second of 2015 • Plan A: Using the Leap Indicator • e have to update our server’s OS/Kernel. • Plan B: Not using the Leap Indicator (Using “Gradually adjust mode” ) • Single Time source (Stratum 1). • We make the Stratum 2 polling interval to Stratum 1 shorter than before (about each 16 seconds). Kyushu Telecommunication Network Co. , Inc. 　 10

The leap second is Coming. June 30, 2015 (UTC) July 1, 2015 +0900 (JST) 23: 59: 58 23: 59: 60 00: 00 08: 59: 58 08: 59: 60 09: 00 00: 01 09: 00: 01 Kyushu Telecommunication Network Co. , Inc. 　 11

Let's do our best. Kyushu Telecommunication Network Co. , Inc. 　 12

Appendix Sites in JPN http: //ringeye. jawfish. org/~ori/misc/leapsecond-20120701. html http: //chicchaki. cocolog-nifty. com/kanetamas_memo/2005/11/ntp_2 b 1 d. html http: //www. rfc-base. org/txt/rfc-2030. txt https: //www. seiko-sol. co. jp/support/download/Leap. Second 20120701_2520_30_40. pdf http: //www-06. ibm. com/jp/linux/tech/doc/0019 db 89. html Sites in English http: //jjy. nict. go. jp/time/teljjy_p 1 -e. html http: //googleblogspot. jp/2011/09/time-technology-and-leaping-seconds. html Kyushu Telecommunication Network Co. , Inc. 　 13