We are converting from ISDN trunks to our Telco to SIP trunks. We already have a Cisco Call Manager cluster and already use SIP trunks. Is any additional licensing needed to convert from ISDN to telco to SIP to telco.
Are you using CUBE to talk between CUCM and your service provider? If so, you need to purchase a CUBE license. FYI, if your provider wants early offer for outbound calls (they typically do) then you need a SIP-SIP CUBE to achieve that. Hence, the majority of SIP ITSP trunks to CM require a CUBE for this reason.
If the SIP trunk is CUCM directly to the ITSP, no licenses necessary, since it is just going to look like any other SIP trunk to a device off of CM.