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Basic GSM Call Flows

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GSM call flows with traces captured from Huawei MSOFT

Published in: Technology, Business

Basic GSM Call Flows

  1. 1. With traces from Huawei MSOFT
  2. 2. BASIC Call Flow  Basic Call Flow 1. Location Update 2. MOC TDM 3. MOC IP 4. MTC TDM 5. MTC IP
  3. 3. Basic Call Flow Location Update (LOC UP)
  4. 4. Location Update
  5. 5. LOC Up: Identity Response
  6. 6. LOC UP: Authentication
  7. 7. LOC UP: AUC Internal Structure AUC RANDOM number generator RAND  IMSI  A3 A8 IMSI ↔Ki Ki Kc  MSC HLR SRES   IMSI  triplet  triplet
  8. 8. LOC UP: Authentication
  9. 9. LOC UP: Authentication   SIM MSC SRES ? SRES = SRES RAND A3 SRES Ki A8 Kc  RAND  RAND SRES Kc
  10. 10. LOC UP: Authentication Request
  11. 11. LOC UP: Authentication Response
  12. 12. LOC UP: Update Location Req
  13. 13. LOC UP: Insert Subscriber Data
  14. 14. LOC: IMEI receive
  15. 15. LOC UP: Ciphering
  16. 16. LOC UP: TMSI Reallocation
  17. 17. Basic Call Flow Mobile Originating Call (MOC)
  18. 18. MOC: Complete call Trace
  19. 19. CM Service Request
  20. 20. Setup message contains the dialed number from the Mobile station (MS) MOC : “Setup” Message
  21. 21. MOC: (SRI) Send Routing Information
  22. 22. MOC: Reply from HLR
  23. 23. Assignment Request
  24. 24. MOC: IAM – Initial Address Message
  25. 25. MOC: ACM – Address Complete Message
  26. 26. MOC: Connect & Release
  27. 27. Basic Call Flow Mobile Terminating Call (MTC)
  28. 28. MTC: Complete Trace
  29. 29. MTC: Provide Roaming Number (PRN)
  30. 30. MTC: PRN Response
  31. 31. MTC: IAM
  32. 32. Paging Request
  33. 33. Paging Response
  34. 34. Set UP
  35. 35. IP CALL
  36. 36. Call Flow through IP( MOC)
  37. 37. BICC TYPE IAM
  38. 38. TO BICC TYPE APM
  39. 39. FROM BICC TYPE APM
  40. 40. Call Flow through IP( MTC)
  41. 41. PRN
  42. 42. PRN Response
  43. 43. BICC TYPE IAM
  44. 44. Set UP
  45. 45. TO BICC TYPE APM
  46. 46. FROM BICC TYPE APM
  47. 47. Assignment Request
  48. 48. ALERT AND BICC TYPE ACM
  49. 49. CONNECT AND BICC TYPE ANM
  50. 50. DISCONNECT AND RELEASE
  51. 51. THANK YOU

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