AASTRA SIP-DECT (Release 2.1)- OM System Manual - Installation, Administration and Maintenance EN - Manual (Page 124)

SIP – DECT OM System Manual Release 2.1 7 Configuration und Administration Aspects
depl-1230/1.3 Page: 124 (196)
As long as an RFP is not in sync, no calls can be established using this RFP.
If an RFP loses the synchronization, the RFP does not accept new calls (“busy bit”). There is
a delay of maximum 3 minutes until the active calls on this RFP are finished. Then it tries to
get synchronized again.
An SIP – DECT installation is more reliable if an RFP can receive the signal from more than
only one RFP because the other signals are also used for synchronization.
The sync-over-air solution is very reliable because all existing redundant paths are used for
synchronization. Thus, hardware tolerances have only very little influence. No RFP has a key
position.
Only unfavorable setups without redundant synchronization paths can cause problems.
Sometimes RFPs do not need to be synchronized, e.g. if they are in different buildings.
These RFPs can be put into different clusters. RFPs in different clusters will not be
synchronized with each other. Different clusters start up at the same time independently.
7.2.1 Initial Synchronization Procedure
To avoid synchronization problems and to speed up the synchronization on system startup,
an initial synchronization procedure will be used. For every cluster the following
synchronization stages are defined.
• Synchronization stage 0
- If at least one preferred RFP was configured, the synchronization process will wait up to
30 seconds for an incoming startup message of such a preferred RFP. Receiving a
message will finishing stage 0 and the synchronization process jumps to stage 1.