| CAS
vs. CCS |
| Tokyo |
| Oulu |
| Exch |
|
|
|
|
|
| User
A |
||||
| (calling |
||||
| user) |
||||
| Exch |
| Exch |
|
|
|
| User
B |
||
| (called |
||
| user) |
||
| Exch |
| Database |
| 1) Accessing database |
| Espoo |
| 2) Signalling before call
setup |
|
|
| 3) Signalling during
conversation phase |
|
| (user-to-user => digital access
technology required) |
|