| Nongatekeeper-Controlled ICT | Gatekeeper-Controlled ICT | H.225 Trunk | |
|---|---|---|---|
| IP address resolution | IP address specified in trunk configuration | IP address resolved by H.323 RAS (gatekeeper) | |
| Gatkeeper call admission | No | Yes, by H.323 RAS (gatekeeper) | |
| Scalability | Limited | Scalable | |
| Peer | Any CUCM | Prior to CUCM 3.2 | CUCM 3.2 or higher and other H.323 devices |