Content for TR 33.856 Word version: 16.1.0
5 Key issues p. 7
5.1 Key Issue #1: Achieving backward security of key derivation during SRVCC from 5G to UTRAN CS p. 7
5.2 Key Issue #2: Security of IMS Emergency Session Handling p. 7
5.3 Key Issue #3: Protecting the SRVCC capability p. 8
5.4 Key Issue #4: 5G UE returning from 3G SRVCC to E-UTRA or NR p. 8
6 Solutions p. 9
6.1 Solution #1.1: Key derivation during SRVCC from 5G to UTRAN CS without direct interface between AMF and MSC server p. 9
6.1.1 Introduction p. 9
6.1.2 Solution details p. 9
6.1.3 Impacts on existing nodes and functionality p. 10
6.1.4 Evaluation p. 10
6.2 Solution #1.2: Key derivation during SRVCC from 5G to UTRAN CS with direct interface between AMF and MSC server p. 10
6.2.1 Introduction p. 10
6.2.2 Solution details p. 11
6.2.3 Impacts on existing nodes and functionality p. 11
6.2.4 Evaluation p. 12
6.3 Solution #2: Emergency session in SRVCC from 5G to UTRAN CS p. 12
6.3.1 Introduction p. 12
6.3.2 Solution details p. 12
6.3.3 Impacts on existing nodes and functionality p. 12
6.3.4 Evaluation p. 12
6.4 Solution #3: Protecting the SRVCC capability p. 12
6.4.1 Introduction p. 12
6.4.2 Solution details p. 13
6.4.3 Impacts on existing nodes and functionality p. 13
6.4.4 Evaluation p. 13
6.5 Solution #4: Return from UTRAN to E-UTRAN or NR p. 13
6.5.1 Introduction p. 13
6.5.2 Solution details p. 13
6.5.3 Impacts on existing nodes and functionality p. 13
6.5.4 Evaluation p. 13
7 Conclusions p. 14
$ Change History p. 16
