supports enabling S6b authentication for 3G access on GGSN service level
For LTE or Wi-Fi
access, S6b authentication is supported on both P-GW service level and APN
level configuration. If the S6b authentication is enabled for particular APN,
when the subscriber joined on LTE transfers to Wi-Fi then 3G, UE does
re-registration of the IMS session on 3G. Different P-GW is selected. However,
SGSN does not update the new P-GW. HSS has the history of the old P-GW. When
the subscriber transfers back to LTE and then to Wi-Fi, it hands over to the
old P-GW. However, the old P-GW does not have the new IMS session and this
result in the handover failure. With this feature, S6b authorization is enabled
for 3G access at the APN level to let P-GW update the new P-GW ID to HSS. This
addresses the inconsistency. Two new CLI keywords have been added at the APN
level to enable S6b authentication for 3G access and GnGp handover.
Previous Behavior: During
a call when S6b communication happened, the same connection state was
maintained across to-and-fro in 3G to 4G handover, although GGSN service did
not have explicit configuration present.
Two new CLI keywords
gn-gp-disabled have been added to the CLI command
authorize-with-hss at the APN level. The keyword
gn-gp-enabled enables the S6b authentication for 3G
access during the call connect and gn-gp handover. The keyword
gn-gp-disabled terminates S6b connection when the
subscriber moves to 3G access. This is used to override the legacy handover
behavior where the session was continued irrespective of the configuration.
These new keywords are not configured by default when
authorize-with-hss egtp are configured. You have to
explicitly enable this customized behavior by configuring the CLI commands
introduced for this feature.