|author||kpfleming <kpfleming@f38db490-d61c-443f-a65b-d21fe96a405b>||2005-04-22 04:39:41 +0000|
|committer||kpfleming <kpfleming@f38db490-d61c-443f-a65b-d21fe96a405b>||2005-04-22 04:39:41 +0000|
more clarification of time changes and how they affect Asterisk (bug #4020)
git-svn-id: http://svn.digium.com/svn/asterisk/trunk@5497 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'README')
1 files changed, 21 insertions, 14 deletions
@@ -164,20 +164,27 @@ from the variables specified above.
* SPECIAL NOTE ON TIME
- Those using SIP phones should be aware the Asterisk is sensitive to large
-jumps in time. Those who live in areas that are on Daylight Savings Time (or
-equivalent) should set their system and hardware clocks to use UTC in order
-to avoid any possible jumps in system time. There should be no noticeable
-effects to the user, as you should still set your system to use the local
-offset from UTC.
- Even for those who don't live in DST zones, this issue may manifest itself
-if the administrator makes large manual time adjustments. Thus, it is good
-practice to keep the time on your Asterisk server synced to a reliable
-source, such as an NTP server.
- Also note that this issue is separate from the clocking of TDM channels, and
-is known to at least affect SIP registrations.
+ Those using SIP phones should be aware the Asterisk is sensitive to
+large jumps in time. Manually changing the system time using date(1)
+(or other similar commands) may cause SIP registrations and other
+internal processes to fail. If your system cannot keep accurate time
+by itself use NTP (http://www.ntp.org/) to keep the system clock
+synchronized to "real time". NTP is designed to keep the system clock
+synchronized by speeding up or slowing down the system clock until it
+is synchronized to "real time" rather than by jumping the time and
+causing discontinuities. Most Linux distributions include precompiled
+versions of NTP. Beware of some time synchronization methods that get
+the correct real time periodically and then manually set the system
+ Apparent time changes due to daylight savings time are just that,
+apparent. The use of daylight savings time in a Linux system is
+purely a user interface issue and does not affect the operation of the
+Linux kernel or Asterisk. The system clock on Linux kernels operates
+on UTC. UTC does not use daylight savings time.
+ Also note that this issue is separate from the clocking of TDM
+channels, and is known to at least affect SIP registrations.
* MORE INFORMATION