OAM Server Redundancy

The PCA application can be deployed with varying degrees of redundancy on the NOAM and SOAM servers. Like the SBR servers, the OAM servers can be configured to support site redundancy if desired.

Regardless of whether site redundancy is supported, the OAM servers must be deployed on redundant servers at a given site.

• Active/Standby NOAM and Active/Standby DR NOAM

  The NOAM servers are deployed using the active/standby redundancy model at one of the sites in the PCA network. If site redundancy is desired, an optional pair of Disaster Recovery (DR) NOAM servers can be deployed at a different site. The DR NOAM servers are used only if manually brought into service following loss of the site where the original NOAM pair was located.

• Active/Standby/Spare SOAM

  If site redundancy is desired for PCA mated pairs, the SOAM servers at each of the mate DSRs should be deployed using the Active/Standby/Spare redundancy model. In this configuration, two SOAM servers are deployed at one site and a third server is deployed at the mate site. The third server is configured as Preferred Spare in the SOAM Server Group. In the event of a site failure, the SBR Servers running at the surviving site of the mated pair will report measurements, events, and alarms to the SOAM server at that site. Without the Spare SOAM server, the Spare SBR servers would have no parent OAM server and would not be able to report measurements, events, and alarms.

SBR servers in a given SBR Server Group must be set up such that they belong to the Signaling Network Element of the site that has two of the three servers. This will allow all three servers in the Server Group to merge their measurements, events, and alarms to the same SOAM Server Group.

Figure 3-14 illustrates how measurements, alarms, and events are merged. MP servers merge to the Active SOAM server for the signaling network element they belong to. The Active SOAM server then replicates the data to its Standby and Spare servers.

Figure 3-14 Data Merging – Normal Case

Figure 3-15 illustrates how a site failure affects merging of alarms, events, and measurements. When Site 2 fails, the servers at Site 1 that were marked as Preferred Spare are promoted to Active. The MP server that is now Active for the SBR Server Group for Site 2 will start merging its data to the SOAM server that is now Active for the SOAM Server Group for Site 2.

Figure 3-15 Data Merging – Redundant Site Failure