AASTRA SIP-DECT (Release 2.1)- OM System Manual - Installation, Administration and Maintenance EN - Manual (Page 151)

SIP – DECT OM System Manual Release 2.1 7 Configuration und Administration Aspects
depl-1230/1.3 Page: 151 (196)
Provided that both OMMs are in contact with each other, their databases are synchronized
automatically.
If the primary OMM fails, the OMM responsibilities are taken over by the standby OMM to
maintain operation. A “No Standby” warning is displayed on the OMM web interface,
indicating that there are no longer two functioning OMMs in the network or cluster.
Configuration changes are done unsafe in this situation.
If the active OMM fails, the inactive OMM recognizes this and begins to act as the active
OMM, and the web service is started.
If the connection between the two OMMs fails, the network or cluster essentially breaks into
two operational parts. The standby OMM now becomes the active OMM. At this point, the
two OMMs cannot detect one another and, therefore, cannot synchronize. When the
connection between the two OMMs is re-established, the synchronization of the OMMs
forces one OMM to become the standby OMM again. Once the recently failed OMM returns
to service and becomes the inactive OMM, it does not resume the role of active OMM.
7.11.1 Configuring OMM Standby
Each RFP of the DECT system have to be configured with two OMM IP addresses. This both
OMM addresses can be either configured via DHCP (see chapter 7.5.1) or with the OM
Configurator (see chapter 7.6).
7.11.2 Fail Over Situations
Fail over occurs under following circumstances:
• An OMM error occurs on the active OMM.
• The RFP acting as the active OMM is shut down or rebooted at the ssh console.
• The OMM is rebooted in the web browser menu.
• The active OMM is unreachable.
The standby OMM becomes the active OMM under following circumstances:
• The configured SIP Proxy/Registrar is reachable.
• The other OMM has a larger IP Address while no OMM is active and both OMMs are in
contact with each other (normally at system startup).
When the OMMs get in contact again:
• Both OMMs check which one ran for a longer period. That one will become the active
OMM. The other one falls back to the standby one.
7.11.3 Fail Over Failure Situations
Fail over failure occurs under following circumstances: The IP connection between OMMs
fails and the configured SIP Proxy/Registrar is unreachable. In this case the active OMM
shall wait until the SIP Proxy/Registrar is reachable.
The following state diagram shows the OMM Standby states: