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Unity failover over wan with CM split cluster


Im looking at a split cluster design for CallManagarer and Unity 5 failover. All the requirements for Unity 5 failover can be met.

The primary server must be on the same side of the firewall as:

• The secondary server

• The Domino message store

• The domain controller/global catalog that Cisco Unity accesses

Requirements for Deploying Cisco Unity Failover Between Two Data Centers for High Availability

For full redundancy at geographically separated data centers, it is possible to set up a failover configuration over a MAN. However, to ensure the successful operation of an installation in this configuration, the following requirements must be met:

• The data centers must be connected with dedicated, customer-managed, leased-line facilities. Carrier-managed bandwidth solutions, for example, IP-cloud handoff, are not supported.

• There must be at least two paths of connectivity between the data centers.

• Each path of connectivity between the data centers must be Optical Carrier level OC-24 (1.244 Gbps) or greater.

• The data centers must not be separated by a firewall.

• The data centers must be no more than 200Km apart.

• Maximum round-trip latency must be no more than 10 ms.

• Each data center must have redundant domain controllers and global catalog servers.

• The Domino environment must be customer owned.

• Call control must be available at each data center.

Scenraio the Devices (3750phones) Primary CM will be located in DC 1 their secondary callmanager will belocated in DC2.

Unity primary will be in DataCentre1 and Unity failover in DC2.

Unity ports will need to be registered to the primary and backup Callmanagers wich are in seperate DC's oconnected over a 10Gig wan.

Is this supported? registering Unity ports to the subscriber server over the wan.

The way the design is thought out is. 3750 phones will be registered to the Callmanager in DC1 and in the event that the Primary CallManager fails the phones 3750 failover to their secondary CM in DataCentre2. The issue we see is that the failover Unity does not come into play unless the primary fails.

Therefore in the above example if the phones primary CM located DC1 with 3750 registered devices failed the phones will failover to their secondary CM call processing server in DC2. The secondary CM located in dataCentre 2 would need to have Unity ports from the active primary Unity server in DC 1 registered to it over the WAN.

Is this supported?

If the above isnt supported one would assume either that

1. Primary and secondary CM must be located in the same DC (pointless)

2.The primary Callmanager and primary unity server fail at the same time and DataCentre2 servers take over (highly unlikely)unless complete disaster of DC

Any ideas



Cisco Employee

Re: Unity failover over wan with CM split cluster

I think your main question is "can Unity register to a CM server over the WAN?" In general the answer is yes. See the first sentence here:

For Unity Failover (over WAN or not) you should plan to have both Unity servers integrated with the same CM servers. So for example, you might have both Unity's configured to use CM1 at DC1 as the primary server and CM2 at DC2 as the secondary. Of course you'll need to ensure sufficient bandwidth for this. When provisioning bandwidth between Unity and CM, treat each Unity port as a individual SCCP phone. A 72 port Unity at DC2 connecting back to CM1 should be treated as if you had 72 SCCP phones at DC2 connecting to CM1.