[Asterisk-cvs] asterisk README,1.29,1.29.2.1

[russell at lists.digium.com]

Update of /usr/cvsroot/asterisk
In directory mongoose.digium.com:/tmp/cvs-serv1014

Modified Files:
      Tag: v1-0
	README 
Log Message:
add note about the effects of time changes (bug #4020)


Index: README
===================================================================
RCS file: /usr/cvsroot/asterisk/README,v
retrieving revision 1.29
retrieving revision 1.29.2.1
diff -u -d -r1.29 -r1.29.2.1
--- README	25 Aug 2004 14:14:57 -0000	1.29
+++ README	10 May 2005 04:09:21 -0000	1.29.2.1
@@ -136,6 +136,30 @@
 the channels 25 through 47 of the tormenta card, obtaining the settings
 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.  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
+clock.
+
+  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
 
 See the doc directory for more documentation.