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Dialogic® PowerMedia® XMS and 2016 Leap Second


A “leap second” is a scheduled adjustment to Coordinated Universal Time (UTC) in order to stay in sync with time derived from Earth's rotation. As of October 2016, the next leap second is scheduled to occur on December 31, 2016 at 23:59:60 UTC, at which exact moment an additional second of time will be added. The purpose of this document is to inform PowerMedia XMS customers and systems integrators how to prepare (or verify their preparation) for this next “leap second” event.


Dialogic has conducted testing to assess the readiness of PowerMedia XMS for the upcoming leap second, and no issues were identified. This testing was performed against PowerMedia XMS 3.1 Service Update 3 and internally on PowerMedia XMS 3.2 builds, which, as of the publication date of this document, had not yet been commercially released. Specifically, the testing consisted of a leap second simulation tool being executed on the PowerMedia XMS system while calls were made to the system. During the testing, Network Time Protocol (“NTP”) was enabled and in step mode. The testing confirmed there was no impact to active audio and video streams (both SIP and WebRTC) during leap second traversal. Test coverage included audio and video play and record, as well as conferencing.

It is important to note that for these testing results to be applicable to commercial XMS deployments, minimum versions of Linux kernel and Java run-time would need to be already in place on the PowerMedia XMS system prior to the occurrence of the upcoming leap second. This is one of several checklist items noted in the section below.

PowerMedia XMS Leap Second Preparation Checklist

Dialogic recommends that PowerMedia XMS customers and systems integrators review and verify the following items for their XMS-based system(s) prior to the occurrence of the upcoming leap second:

  • Ensure the underlying operating system on PowerMedia XMS servers is up to date with patches related to leap seconds (see, e.g.,
  • Ensure that PowerMedia XMS servers have an up to date Java JDK installed, as well as the latest Java Timezone Updater tool version. To do so, visit this page (
  • PowerMedia XMS based servers should be configured with Network Time Protocol (“NTP”) enabled. It is acceptable for NTP to be in either step mode or slew mode; however, whichever mode is chosen should be consistent across all network servers.
  • If a hypervisor is being used, ensure that the hypervisor platform (e.g., vmware, kvm) is up to date with patches related to leap seconds (see, e.g.

In the event that any XMS-related issues are encountered during the verification process, please report them to Dialogic Services.

Once these items have been verified, and well in advance of the occurrence of the upcoming leap second, Dialogic also recommends that potentially affected customers review and test their complete solution to verify that end clients, application servers and other components outside of PowerMedia XMS are equipped to properly handle the leap second transition.


Product List:

Dialogic® PowerMedia™ XMS Release 3.1

Dialogic® PowerMedia™ XMS Release 3.2  


Legal Note:

This document discusses one or more open source products, systems and/or releases. Dialogic is not responsible for your decision to use open source in connection with Dialogic products (including without limitation those referred to herein), nor is Dialogic responsible for any present or future effects such usage might have, including without limitation effects on your products, your business, or your intellectual property rights.


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First published: 18-Oct-2016
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