AASTRA SIP-DECT (Release 1.8)-Installation- and Administration Guide EN - Manual (Page 71)

Installation, Administration and Maintenance
Aastra depl-0900/0.4 Page: 71 (104)
5 OMM Resiliency
To perform OMM Resiliency, two OpenMobility Managers have to be
provided in an OMM network. One is working as the „master“ OMM, and the
other one is working as the resilient or standby OMM.
In the event that the RFP designated as the OMM fails, the other RFP,
designated as the secondary OMM automatically assumes the role of the
OpenMobility Manager.
5.1 How OMM Resiliency Works
During system start-up, each IP RFP retrieves either one (if non-OMM
resilient) or two (if OMM resiliency is configured) OMM IP addresses and
both try to connect to each other. The active or „master“ OMM will serve all
connections from RFPs’. The resilient or standby OMM will refuse all
connection attempts from RFPs’.
5.2 Introduction
During normal operations, both the active and the standby/resilient OMM are
in contact and monitor each other’s operational state. They continually
exchange their current resiliency states and the standby OMM receives a
copy of any configuration changes on the active OMM. Provided that both
OMMs’ are in contact with each other, their databases are synchronised
automatically.
If the primary OMM fails, the OMM responsibilities are taken over by the
standby OMM to maintain operation. A “No Resiliency” warning is displayed
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 recognises this and begins to act
as the active OMM, and the web service is started. All IP RFPs’ being
maintained by the OMM will be restarted and all Portable Parts will be
resynchronised. If the connection between the two OMMs fails, the network
or cluster essentially breaks into two operational parts. The resilient or
standby OMM now becomes the active OMM. At this point, the two OMMs
cannot detect one another and, therefore, cannot synchronise. When the
connection between the two OMMs is re-established, the synchronisation of
the OMMs forces one OMM to become the standby once again. Once the
recently failed OMM returns to service and becomes the inactive OMM, it
does not resume the role of active OMM.
5.3 Configuring OMM Resiliency
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 3.1.1) or with the OM Configurator (see chapter 3.2).
5.4 Fall Over Situations