RG              UP                       CP             AAA
     | Online Request|                        |               |
    1|-------------->|                        |               |
     |               |Relay the Online Request|               |
     |              2|-----to CP via Si------>| Authentication|
     |               |                        |    Req/Rep    |
     |               |                       3|<------------->|
     |               |  Create Subscriber     |               |
     |               |   Session Request      |               |
     |              4|<--------via Ci---------|               |
     |               |                        |               |
     |               |  Create Subscriber     |               |
     |               |   Session Response     |               |
     |              5|---------via Ci-------->|               |
     |               |                        |   Accounting  |
     |               |                       6|<------------->|
     |               |  Send Online Response  |               |
     |              7|<----to UP via Si-------|               |
     |               |                        |               |
     |Online Response|                        |               |
    8|<--------------|                        |               |
     |               |                        |               |