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CCX 8.5 in HA over WAN on Island Mode

Hi guys,

Does anyone know what will happen with CCX 8.5 in HA over WAN configuration goes to island mode?

So consider the following setup

Site A Site B

CUCM Node --- WAN --- CUCM Node

CCX Primary CCX Standby

Each site have their own local voice gateway and sets of agents.

The SRND covers that if 10 consecutive heartbeat is lost then a failover will be triggered.

However the SRND does not cover the scenario if the WAN is totally cut and Site A and Site B is completely isolated from each other.

Does anyone know what will happen in this situation? Will both CCX Node become Primary and operate in its own right (just like Unity Connection cluster when they go to island mode)?

Kind regards


Everyone's tags (3)

CCX 8.5 in HA over WAN on Island Mode


In UCCX's HAoWAN Island mode, both sides will be active & process calls simultaneously, as they feel the other side node is down ( as the WAN link between them is down ). This is known as Split-Brain situation in UCCE terms.

It is described nicely in the VoD available here . Island mode description starts after 7th minute of VoD.

Hope it helps ?


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Cisco Employee

CCX 8.5 in HA over WAN on Island Mode


Here is more of a "step by step" to your question:

Page 68:

When the WAN link has a clean break:

and by clean break I mean it goes down and stays down, it does not

flap or provide intermittent connectivity

1) The CAD agents will connect to UCCX server that they can communicate with

2) The UCCX servers will connect to the CUCM Node that they can connect

to for call processing

3) The calls that get to the respective UCCX servers will go to the

respective agents

When the WAN Link is restored:

1) The Nodes will decide which node is more "qualified" to become the

master node, this is generally Node 1 aka the first node that was built

in the cluster

2) The CAD Agents connected to the node that becomes the secondary will

fail over to Node 1 to begin accepting calls from it

3) All of the calls that the new master Node were processing will not

have any negative affect as they will continue to be processed by UCCX

4) The calls that are in queue for the node that becomes the slave in

the cluster will be dropped

New Member

When in island mode are there

When in island mode are there services that are impacted?  Moh, Extension Mobility, QM recordings?  Thank You.

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