In which three situations would an IP-to-IP gateway be useful? (Choose three.)
A.
two organizations have merged and both use SCCP signaling
B.
an organization would like to migrate from H.323 to SIP
C.
an organization has deployed a SIP IP telephony solution and needs to connect to a SIP service provider
D.
an organization needs to migrate from a Cisco Unified CallManager IP telephony solution based on SCCP to an H.323 solution.
E.
an organization using H.323 needs to integrate an acquisition that also uses H.323
F.
an organization needs to integrate larger PSTN gateways into their SIP network