Baseband behavior on IMSI change » History » Version 4
neels, 02/25/2020 07:40 PM
| 1 | 1 | neels | h1. Baseband behavior on IMSI change |
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| 3 | 4 | neels | h1. With "Proactive SIM" REFRESH command |
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| 5 | TODO |
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| 7 | |||
| 8 | h1. Without "Proactive SIM" REFRESH command |
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| 10 | 3 | neels | | phone | chipset | behavior scheme | directly when writing new IMSI to SIM file | on CM Service Request | after periodical LU period | after flight mode / phone restart | on Identity Request | |
| 11 | | Nokia | | (I) | no reaction | uses previous TMSI | uses previous TMSI | uses previous TMSI | returns new IMSI | |
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| 12 | | Samsung Galaxy S4m | | (I) | no reaction | uses previous TMSI | uses previous TMSI | uses previous TMSI | returns new IMSI | |
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| 13 | 2 | neels | |
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| 15 | h2. (I) Keeps TMSI |
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| 17 | Even though the IMSI has changed, the Baseband remains actively attached. |
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| 18 | On contact with the core network, it uses the last TMSI, and hence looks as if it remained completely unchanged, keeps using the previous identity. |
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| 19 | After a power cycle, it also uses the last TMSI. |
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| 21 | When the MSC has forgotten the last TMSI (e.g. due to IMSI Detach), the Identity Request is answered with the new IMSI, and the phone has thus switched to the new identity. |
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| 22 | |||
| 23 | Needs: |
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| 24 | |||
| 25 | * make the MSC forget the TMSI |
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| 26 | * trigger baseband activity to cause a re-attach with the new IMSI |
