Christina Hattingh, technical marketing engineer in the branch office Cisco Unified Communications group states:
|CUBE can perform many different functions, there are various reasons to deploy a CUBE, and various places in the network where it may fit.
Only a subset of these may apply to a particular network situation.
Some of the common ones include:
H.323 to SIP interop:
If you have an older CUCM cluster capable only of H.323 and wish to deploy/upgrade another CUCM cluster to a newer release that is SIP-capable, you can bridge these two realms by putting a CUBE in the middle to provide H.323-SIP interop until such time as you upgrade all CUCMs to SIP.
Following on from above, you could connect an H.323 CUCM cluster to any newer SIP gear in your network if you wish to start deploying SIP proxies, MCUs, apps... but do not wish yet to upgrade your CUCM.
One place where where this is used is with MeetingPlace using SIP.
IP address hiding: If you have a merger/acquisition in your enterprise and have to integrate voice equipment (CUCMs, IP PBXs VM servers, etc.) that have overlapping IP addresses with the rest of your network, you could use a CUBE to connect the two distinct networks until such time as they can be migrated into your enterprise addressing plan. Following from the above situation, if there are any security concerns between your network and the "acquired" network, a CUBE (being a B2BUA) can provide a demarc between the two networks to mask one from the other until the security issues are worked out and you no longer need a demarc.
SIP Trunk termination: If you bring a SIP trunk from a SP into your enterprise, it's best to terminate this onto a CUBE and not directly onto CUCM. This practise provides security, topology hiding, transcoding, call admission control, protocol normalization, SIP registration, and various other network demarc capabilities that you would lose if you connect directly to CUCM (and which you had with TDM GWs to the PSTN).
ICT CAC: If you need RSVP CAC on your H.323 ICTs between CUCM clusters, CUBE can provide this function.