Enhanced Survivability feature provides an on-premises calling only failover capability in an event of a customer network outage, or any cloud outage preventing users at that site from connecting to Webex Calling Dedicated Instance.
Overview
In an unlikely event of a customer’s network outage, or a cloud outage, preventing users at that site from connecting to Webex Calling Dedicated Instance, the Enhanced Survivability Node actively takes over the call routing responsibility. Throughout the outage, the Enhanced Survivability Node will process all Intra-site, PSTN and Emergency calls for the users in that site.
The Enhanced Survivability Node is used during any of the following events:
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Customer Network outage – for e.g. WAN or ISP outage.
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Dedicated Instance Calling service is unavilable.
Solution Overview
A Unified CM node deployed in Customer’s data center connects to the Dedicated Instance Unified CM Cluster as an Enhanced Survivability Node.
During a survivability event, all the devices and third-party integrations that support Enhanced Survivability Node will failover.

The following are the key specifications for an Enhanced Survivability Node:
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A maximum of only 8 Enhanced Survivability Nodes can be deployed in a single Unified CM cluster.
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The round-trip time (RTT) between the Unified CM cluster in Dedicated Instance and the enhanced survivability node should be equal or less than 200 milliseconds.
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A maximum of 7500 devices can be registered on the Enhanced Survivability Node during an event of Survivability.
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The feature is supported only on Edge or Partner Connect, cloud connectivity options.
The following are the key specifications for an Enhanced Survivability Node:The following table lists the feature comparison between SRST and Enhanced Survivability Node:
Call Scenarios |
SRST |
Enhanced Survivability Node |
Basic and Supplementary Calls (Inbound, Outbound, Hold/Resume) |
Yes |
Yes |
PSTN Calls |
Yes |
Yes |
Nomadic E911 Support |
Yes |
Yes |
EPIC CRM Integration |
No |
Yes |
SIP integrations |
Yes |
Yes |
No |
Yes |
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Paging Support (with CTI) |
No |
Yes |
How to order
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Navigate to the CCW Ordering site, and then click Login to sign on to the site:https://apps.cisco.com/Commerce/guest. |
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Click Create Estimate and add A-FLEX-3 SKU. |
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Click Select Options and add the respective SKUs for Webex Calling. |
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Select “Webex Calling Dedicated Instance” and “Enhanced Survivability for Webex Calling Dedicated Instance” and provide the region quantity. The region quantity can equal or less than the Webex Calling Dedicated Instance region quantity. Below are SKU names for the feature: A-FLEX-DI-ESV (applies to both Suite an EA) A-FLEX-DI-NU-ESV (applies to NU) A-FLEX-DI-ESV-E (applies to EDU in FLEX 3) A-FLEX-DI-NU-ESV-E (applies to EDU in FLEX 3)
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Enable Enhanced Survivability
Refer Prerequisite to follow firewall, DNS, and proxy server settings configuration before continuing with the enhanced survivability
node installation and activation.
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Once the Enhanced Survivability feature has been added to the subscription, in Control Hub you need to enable the feature for a particular region, where the Enhanced Survivability Node will be deployed.
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Sign-in to Control Hub https://admin.webex.com/login, navigate to . ![]()
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Click Enable for the region to initiate the Enhanced Survivability activation.
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When successfully enabled, the Enhanced Survivability tile is visible in the Unified CM publisher's right panel in the respective region. ![]()
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Add Enhanced Survivability Node
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Navigate to Calling > Dedicated Instance > Manage tab and choose a region. Under the region, select the Unified CM publisher for which the Enhanced Survivability Node must be added. |
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In the Enhanced Survivability tile, click Add Survivability Node. |
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Provide the IP address for the list of nodes and click Confirm. We provide the Enhanced Survivability Node’s Hostname. While installing the Enhanced survivability node, you should use the same Hostname and IP address. ![]()
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Click Confirm and the summary page appears. |
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The summary page will provide all the details that requires for you to install the Enhanced Survivability Node. Click Export to download the detailed document. The downloadable export file has all the required details to install the Enhanced Survivability Node in your on-premises, such as:
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Install Enhanced Survivability Node
The Enhanced Survivability Node installation is the responsibility of the customer or partner. You need to install the Unified CM publisher node (standalone) in the data center (preferably the branch site location). See the following details during installation:
The Enhanced Survivability Node should be the same version as the Dedicated Instance Unified CM version. The version details are provided in the downloadable export file, refer Add survivability node to a Unified CM cluster.
As mentioned in How to order Enhanced Survivability, after placing the order for Enhanced Survivability in CCW, an email with the link for downloading the Unified CM bootable ISO will be sent to the e-delivery email address.
We provide the link to only the main release bootable ISO of Unified CM and if you want to install a different version, first you must install the main release version and then upgrade to the same version as the Dedicated Instance cluster. |
Enhanced Survivability Node is supported in Unified CM version V14 SU3 and above.
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It is necessary for the enhanced survivability node to be reachable from Dedicated Instance cloud through the existing peering.
Activate Enhanced Survivability Node
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In Control Hub, navigate to . |
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Select the desired Unified CM Publisher node> Enhanced Survivability and Click Activate for the Enhanced Survivability Node that needs to be added to the cluster as survivable node. |
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In the activation form, the admin would need to confirm that the Enhanced Survivability Node has been installed in the customer’s
datacenter with the mentioned hostname and IP address.
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The following details of the Enhanced Survivability Node installed needs to be provided to Cisco and this information is used
for the conversion of Unified CM publisher node to Enhanced Survivability Node in the customer premise. OS admin username
and password is of the RSN installed by the customer in their premise.
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Click Activate and then Confirm to start the Activation of Enhanced Survivability Node.
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The status of the activation can be viewed under, Select Unified CM Publisher node and in the right hand panel the Enhanced Survivability tile will show the status. Following is the status for survivability node:
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Troubleshooting
OS administrator username and password error

The OS administrator username and password or the security password provided in the activation form is not correct and Cisco is not able to connect to the Enhanced Survivability Node using the same. The issue can be fixed by, clicking on Update Credentials and provide the correct credentials to re-start the activation process.
Enhanced Survivability Node version and node type error

Make sure the Enhanced Survivability Node installed in the customer premise is a stand-alone publisher node and version is the same as of the Unified CM publisher in Dedicated Instance. Once the corrections are done, click on Continue to re-start the activation process.
Firewall port error

Make sure all the firewall ports and IP address configurations are done as mentioned in the section “Network and Security settings on Customer premise”. Once the corrections are done, click on Continue to re-start the activation process.
Unified CM Certificate Alert

You will receive the alert if you manage the Cisco Unified CM certificates. You have to sign the CallManager Certificate and Tomcat Certificate and upload to all the Unified CM nodes in the cluster.
While signing, make sure the Enhanced Survivability node is included. |
Once the certificates are signed and uploaded, to continue with Activation, select the checkbox and click on Activate.
Proxy server error

The proxy server settings need to be correct for the node to reach the Cisco Cloud. For more information refer “Proxy Server Settings” and once the proxy is fixed the activation can be re-triggered by clicking on Continue.