| {hscale=2} |
| ms = MS,BSS |
| msc = MSC |
| hlr = HLR proxy |
| home = Home HLR |
| |
| ms -> msc CM Service Request / Paging Response |
| msc -> hlr Send Auth Info Request |
| hlr () . Use already set up proxy path |
| hlr <> . All cached auth tuples have been sent to the MSC before |
| --- If no GSM AKA fallback is allowed |
| msc <- hlr Send Auth Info Error |
| ms () msc Detach |
| --- If GSM AKA fallback is allowed |
| hlr () . (6) Resend only GSM AKA tuples, already sent earlier |
| msc <- hlr Send Auth Info Result |
| containing GSM AKA auth tuples |
| from the proxy cache |
| ms () msc 2G: Authentication |
| 3G: Detach |
| ms () msc Continue the CM Service / Paging action |