AASTRA SIP-DECT (Release 1.8)-Installation- and Administration Guide EN - Manual (Page 73)

Installation, Administration and Maintenance
Aastra depl-0900/0.4 Page: 73 (104)
PBX not reachable
(registration and OPTIONS
request failes)
OMM sync NOK and
PBX unreachable
In this state the DECT air interface might not be in a definite
state, when both OMMs are active but do not see each other!
In this case a network problem occurs (broken into two parts)
which is very theoretical and we can not handle. There might
be two DECT systems with the same PARK active. For this
case it is random which RFP is connected to the one or to the
other OMM.
In this state hand over might be reduced (not all RFPs might
be synchronised).
OMM sync OK
Another OMM is running
for a longer period
OMM sync OK
OMM sync NOK
OMM Start up
or Restart
Synchronised
Inactive OMM
OMM star up sync
OK
Unsynchronised
Inactive OMM
OMM sync NOK and
PBX reachable
OMM sync OK
other OMM is active
OMM sync NOK
Synchronised
Active OMM
Unsynchronised
Active OMM
No OMM is active and
I have the lowest IP address
OMM sync OK
only one OMM is active
PBX not reachable
(registration and
OPTIONS request
failes)
PBX reachable
(registration or OPTIONS
request OK)
„OMM sync OK“ means: OMMs are synchronised with each other and are able to exchange their operational states
„OMM sync NOK“ means: OMMs are not synchronised with each other and are not able to exchange their operational states
OMM – Reset with exit code 45 OMM – Reset with exit code 46
5.6 Specific Resilient Situations
Some aspects have to looked at in case of OMM state changes when they
are unsynchronised.
5.6.1 How A Resilient OMM Becomes Active
As the above figure shows in case of an unsynchronized OMM state the
standby OMM has to decide whether to become active or not.
For this purpose the OMM tries to contact the configured SIP proxy and
registrar. The OMM starts a SIP registration for the handset with the lowest
phone number and sends an OPTIONS request to the configured proxy. If
there is an answer the SIP proxy/registrar will be considered as reachable
and the OMM becomes active.
5.6.2 Handling When Both OMMs’ Are Not Synchronized
In an unsynchronized OMM resiliency state the connection between the
OMMs’ is broken. In case of a network problem both OMMs’ might be in this
state. During this time an inconsistent OpenMobility system is working with
some constraints.
The WEB service will warn with the warning “No Resiliency” for both OMMs’
in this situation and possible made configuration changes are not save.