Have this question for the Cisco Cloud Webex calling feature when working with an ISR4k that is On Customer Prem, does the ISR require purchasing SIP trunk licenses for the users?
CUBE calling licenses are required. For new gateways, the licenses are already included in a Webex Calling Flex subscription.
SIP trunk direct to the Internet telephony service provider (ITSP) or via intermediary call control supported on all platforms listed in this document. CUBE Trunk Licenses (CUBE-T-RED) are included as part of your Cisco Webex Calling subscription at a ratio of 1 license for every 2 users. These licenses must be requested by opening a case with email@example.com once the Flex Plan subscription order is placed. The licenses themselves will have an expiry date and will require that the Cisco IOS-XE software be updated once the licenses expire to a future version that will remove the requirement for this process. The licenses will not expire before this Cisco IOS-XE software version is released. Therefore, it is not necessary to order any CUBE Trunk Licenses for the Webex Calling Local Gateway functionality.
Have your customer send a request to firstname.lastname@example.org asking for the Cube licenses included with their subscription.