RG              UP                      CP              AAA
     |  PPPoE Disc   |        PPPoE Disc      |               |
    1|<------------->|<---------via Si------->|               |
     |               |                        |               |
     |  PPP LCP      |        PPP LCP         |               |
    2|<------------->|<---------via Si------->|               |
     |               |                        |      AAA      |
     |  PPP PAP/CHAP |        PPP PAP/CHAP    |    Req/Rep    |
    3|<------------->|<---------via Si------->|<------------->|
     |               |                        |               |
     |  PPP IPCP     |        PPP IPCP        |               |
    4|<------------->|<---------via Si------->|               |
     |               |                        |               |
     |               |  Create Subscriber     |               |
     |               |   Session Request      |               |
     |              5|<--------via Ci---------|               |
     |               |  Create Subscriber     |               |
     |               |   Session Response     |               |
     |              6|---------via Ci-------->|               |
     |               |                        |   Accounting  |
     |               |                       7|<------------->|
     |               |                        |               |